CN106028914A - Systems and methods for determining lesion depth using fluorescence imaging - Google Patents

Abstract

Systems, catheter and methods for treating Atrial Fibrillation (AF) are provided, which are configured to illuminate a heart tissue having a lesion site; obtain a mitochondrial nicotinamide adenine dinucleotide hydrogen (NADH) fluorescence intensity from the illuminated heart tissue along a first line across the lesion site; create a 2-dimensional (2D) map of the depth of the lesion site along the first line based on the NADH fluorescence intensity; and determine a depth of the lesion site at a selected point along the first line from the 2D map, wherein a lower NADH fluorescence intensity corresponds to a greater depth in the lesion site and a higher NADH fluorescence intensity corresponds to an unablated tissue. The process may be repeated to create a 3 dimensional map of the depth of the lesion.

Description

Systems and methods for determining lesion depth using fluorescence imaging

related application

This application claims the benefit and priority of U.S. Application Serial No. 14/541,991, filed November 14, 2014, and claims the benefit and priority of U.S. Provisional Application Serial No. 61/904,018, filed November 14, 2013, The entire contents of both are incorporated herein by reference in their entirety.

technical field

The present disclosure generally relates to the medical procedure of applying ablative energy to the body to create a therapeutic lesion. In particular, the present disclosure relates to systems and methods for imaging lesions and tissue to determine lesion depth.

Background technique

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia worldwide, currently affecting millions of people. In the United States, AF is expected to affect 10 million people by 2050. AF is associated with increased mortality, morbidity, affects quality of life, and is an independent risk factor for stroke. The substantial lifetime risk of developing AF adds to the public health burden of the disease, which amounts to more than seven billion dollars in annual treatment costs in the United States alone.

Most seizures in patients with AF are known to be triggered by focal electrical activity arising from within the muscular sleeve extending into the pulmonary vein (PV). AF can also be triggered by focal activity within the superior vena cava or other atrial structures (ie, other cardiac tissue within the conduction system of the heart). These focal triggers can also cause atrial tachycardia driven by reentrant electrical activity (or rotor), which can then segment into the multiple electrical wavelets that are characteristic of atrial fibrillation. In addition, long-term AF can cause functional changes in the cardiac cell membranes, and these changes further perpetuate AF.

Radiofrequency ablation (RFA), laser ablation, and cryoablation are the most common techniques of catheter-based mapping and ablation systems used by physicians to treat atrial fibrillation. Physicians use catheters to direct energy to either destroy a focal trigger or create an electrically isolated line that isolates the trigger from the rest of the heart's conductive system. The latter technique is commonly used in so-called pulmonary vein isolation (PVI). However, the success rate of AF ablation methods has remained relatively stagnant, with relapse rates estimated to be as high as 30% to 50% one year after the procedure. The most common cause of recurrence after catheter ablation is one or more gaps in the PVI wire. The gap is often the result of ineffective or incomplete ablation, which can temporarily block the electrical signal during the procedure, but heals over time and promotes recurrence of atrial fibrillation.

Therefore, there is a need to develop and validate appropriate ablation, reduce fluoroscopy time, and reduce arrhythmia incidence, thereby improving outcomes and reducing costs.

Contents of the invention

According to some aspects of the present disclosure, there is provided a method for determining the depth of an ablation site, the method comprising: irradiating cardiac tissue having a lesion site; Mitochondrial nicotinamide adenine dinucleotide hydrogen (NADH) fluorescence intensity was obtained from irradiated heart tissue; a 2-dimensional (2D) map of the depth of the lesion site was created along the first row based on the NADH fluorescence intensity map; and determining the depth of the lesion site at selected points along the first row from the 2D map, wherein lower NADH fluorescence intensities correspond to greater depths in the lesion site, Whereas higher NADH fluorescence intensity corresponds to non-ablated tissue.

In some embodiments, the method further comprises creating a lesion site in cardiac tissue by ablating. The obtaining step may include: detecting NADH fluorescence from the irradiated tissue; creating a digital image of the lesion site from the NADH fluorescence, the digital image comprising a plurality of pixels; and determining The NADH fluorescence intensities of the multiple pixels lined up. In some embodiments, the method further comprises: distinguishing the lesion site from the healthy tissue in the digital image based on the amount of NADH fluorescence from the lesion site and healthy tissue; The digital images were normalized to the NADH fluorescence intensity of pixels representing the healthy tissue.

In some embodiments, the detecting step comprises filtering the NADH fluorescence through a bandpass filter of about 435 nm to 485 nm. In some embodiments, the healthy tissue has a lighter appearance and the lesion site has a darker appearance. The creating step may include plotting NADH fluorescence intensity along the line across the lesion site to create a 2D map of the depth of the lesion site.

In some embodiments, the method further comprises: obtaining NADH fluorescence intensity from irradiated cardiac tissue along a second row across the lesion site; creating along the second row based on the NADH fluorescence intensity a 2D map of the depth of the lesion site; and constructing a 3-dimensional (3D) image of the lesion site from the 2D map along the first row and the 2D map along the second row. In some embodiments, the steps of obtaining, creating and determining may be repeated multiple times along a vertical line across the width of the lesion, each 2D map of the depth being parallel to a line along the length of the lesion. and integrating each of the 2D images of the depth of the lesion on a vertical line to reconstruct a 3D image of the depth of the lesion.

The determining step may include applying a pixel grayscale ranging from completely black to completely white. The method can be used to analyze epicardial tissue, endocardial tissue, atrial tissue and ventricular tissue.

In some embodiments, the irradiating step includes irradiating the cardiac tissue with laser-generated UV light, wherein the laser-generated UV light may have a wavelength of about 300 nm to about 400 nm.

According to some aspects of the present disclosure, there is provided a system for imaging cardiac tissue, the system comprising: an illumination device configured to irradiate tissue having a lesion site to stimulate mitochondria in the tissue Nicotinamide adenine dinucleotide hydrogen (NADH); an imaging device configured to detect NADH fluorescence from irradiated tissue; and a controller in communication with the imaging device to program the The controller obtains NADH fluorescence intensity from irradiated tissue along a first row across the lesion site; creating a 2-dimensional map of the depth of the lesion site along the first row based on the NADH fluorescence intensity (2D) map; and determining from said 2D map the depth of said lesion site at a selected point along said first row, wherein lower NADH fluorescence intensity corresponds to a greater depth in said lesion site Large depths and higher NADH fluorescence intensity correspond to non-ablated tissue.

According to some aspects of the present disclosure, there is provided a system for imaging cardiac tissue comprising: a catheter having a distal region and a proximal region; a light source; an optical fiber extending from the light source to The distal region of the catheter to irradiate the tissue with the lesion site near the distal end of the catheter to stimulate the nicotinamide adenine dinucleotide hydrogen (NADH) of the mitochondria in the tissue; the image beam ( image bundle), the image bundle is used to detect NADH fluorescence from the irradiated tissue; a camera connected to the image bundle, the camera is configured to receive the NADH fluorescence from the irradiated tissue, and generate the NADH fluorescence from the irradiated tissue a digital image of irradiated tissue, the digital image comprising a plurality of pixels; and a controller in communication with the camera, the controller configured to determine from the digital image along NADH fluorescence intensities of the plurality of pixels in a first row of the site; creating a 2D map of the depth of the lesion along the first row based on the NADH fluorescence intensities; and determining from the 2D map along The depth of the lesion site at the selected point of the first row, wherein lower NADH fluorescence intensity corresponds to a greater depth in the lesion site, and higher NADH fluorescence intensity corresponds to non-ablated organize.

Description of drawings

The presently disclosed embodiments will be further explained with reference to the drawings, in which like structures are represented by like numerals throughout the several views. The drawings shown are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the presently disclosed embodiments.

FIG. 1A is a system structure diagram of an embodiment system of the present disclosure.

Figure IB is a block diagram of an embodiment system of the present disclosure.

FIG. 1C is a diagram illustrating an exemplary computer system suitable for use with the systems and methods of the present disclosure.

Figure 2 is a view of a dedicated catheter according to one embodiment of the present disclosure.

3 is a close-up photograph of an inflated catheter balloon and tip according to one aspect of the present disclosure.

4A is a flowchart of a method according to the present disclosure.

4B is a flowchart of a method according to the present disclosure.

4C-4F illustrate depth analysis along a single row according to the present disclosure.

Figures 4G and 4H show depth analysis in 3D according to the present disclosure, where two ablation lesions and the inter-lesion space are imaged by fNADH.

5A and 5B are side-by-side graphs of emission wavelengths for healthy cardiac tissue (FIG. 5A) and ablated cardiac tissue (FIG. 5B);

6A and 6B are side-by-side image comparisons of cardiac lesion foci under white light irradiation (FIG. 6A) and NADH fluorescence due to UV light irradiation (FIG. 6B).

FIG. 7A is a photograph showing an epicardial image viewed under UV illumination showing lesion diameter measurements.

Figure 7B is a photograph of the diameter of the same lesion in Figure 7A measured but stained with triphenyltetrazolium chloride (TTC).

Figure 7C is a graph of the correlation of lesion size diameter measurements of fluorescent lesions and TTC-stained lesions.

Figure 8A is a graph of the correlation between lesion depth and NADH fluorescence.

Figure 8B is a photograph of diameter measurements of two lesion foci revealed by staining with TTC.

Figure 8C is a photograph of diameter measurements of fNAHD visualized lesions.

FIG. 8D is an inverted signal of FIG. 8C.

Figure 9 is a graph of compiled data comparing lesion depth to anti-NADH fluorescence intensity.

Figure 10 is a 3D reconstruction of the lesion depth.

Figure 11 is a graph of NADH fluorescence intensity versus lesion depth as a function of ablation duration (time).

12A and 12B respectively illustrate a lesion foci formed by cryoablation and a 3D map of a lesion foci.

Fig. 12C and Fig. 12D respectively illustrate the lesion foci formed by radiofrequency ablation and the 3D images of the lesion foci.

Figures 12E and 12F respectively illustrate three different lesions and a 3D map showing the physical relationship of the corresponding depths of the lesions. Lesion interfocal gaps are exemplified on 3-D reconstructed images.

Figure 13A is an image of a lesion foci formed by cryoprobing.

Figure 13B is an enlargement of the lesion in Figure 13A.

Figure 13C is a 3D image of a lesion foci formed by the cryoprobe of Figure 13A.

Figure 14 shows a graph of epicardial fNADH intensity correlated in an inverse fashion with actual lesion depth as measured by TTC analysis.

While the above figures illustrate presently disclosed embodiments, as noted in the discussion, other embodiments are also contemplated. This disclosure presents illustrative embodiments by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope and spirit of the principles of the presently disclosed embodiments.

detailed description

The present disclosure generally relates to medical procedures for applying radiofrequency, laser, or cryoablative energy to the body to create a therapeutic lesion. In particular, the present disclosure relates to systems and methods that can use mitochondrial nicotinamide adenine dinucleotide hydrogen (NADH) fluorescence (fNADH) to image cardiac lesion foci and tissue. The present systems and methods may be used during the treatment of atrial fibrillation (AF). In particular, the present disclosure relates to systems and methods for generating a lesion depth map by analyzing NADH fluorescence intensity data to determine lesion depth. In some embodiments, the present systems and methods can be used to determine the depth of a lesion in cardiac tissue (epicardial tissue, endocardial tissue, atrial tissue, and ventricular tissue). However, the presently disclosed methods and systems can also be applied to the analysis of lesions in other tissue types. The lesion to be analyzed can be generated by ablation during the ablation process. In some embodiments, pre-existing lesions created by ablation or by other means can also be analyzed using the methods and systems disclosed herein.

According to some aspects of the present disclosure, endogenous NADH fluorescence (fNADH) in cardiac tissue can be imaged in real time to identify ablated and non-ablated regions. Gaps between ablated regions can be identified using fNADH imaging, and the gaps can then be ablated. Imaging can be performed during ablation and does not require additional chemicals such as contrast agents, tracers or dyes.

In some embodiments, the intensity of the fluorescence can be measured and plotted, where the lowest fluorescence (darkest) corresponds to the deepest ablated lesion and the highest fluorescence (brightest) corresponds to non-ablated or healthy tissue. Any gray level between the light and dark extremes generally corresponds to the degree of depth of the tissue lesion. The presently disclosed systems and methods can be used to determine lesion depth based on pixel intensities obtained after tissue is ablated and imaged using an fNADH system. In some embodiments, the associated depth data can be integrated into the 3D reconstruction of the lesion providing the physician with timely feedback on lesion geometry and quality. Thus, the present disclosure addresses the lack of lesion quality feedback of today's known techniques and methods by providing lesion depth information to the physician while performing the procedure. For example, having depth information can be used for subsequent diagnosis and treatment. In performing an ablation procedure, particularly a pulmonary vein isolation procedure, at least one of several objectives is to deliver an ablation lesion deep enough to have lasting results and to increase the success rate of the procedure. In this procedure, it is optimal that the ablated lesions have no gaps and each lesion has covered sufficient depth. This is known as a transmural lesion (which means no damage to tissue outside the heart or perforation of the heart) so that depth information is used during the procedure to help the operator go deep enough to provide appropriate results and Better lesion focus for longer lasting results. Furthermore, the lesion generated is largely dependent on the ablation tool used, such as RFA (standard or perfusion), cryo (catheter or balloon), and laser, all of which produce lesions of different shapes. It is a challenge to overcome the dependence of the generated lesion on the ablation tool used, which results in each ablation tool having different depths, some deeper than others. In performing an ablation there is no minimum depth number, which may depend on several factors such as the area being ablated, the atria being thinner than the ventricles or some other factor. For example, a depth of 2 mm may be optimal for atrial tissue but poor for ventricular tissue, however, each patient will have different thicknesses of tissue and require specific attention.

As mentioned above, a high quality and verifiable lesion can be at least some of the key factors in the success of the ablation procedure and in avoiding recurrence. A quality lesion can be of sufficient depth and cause complete necrosis (ie, transmural) of cells from the endocardial surface to the epicardial surface of the heart while minimizing damage to other non-cardiac structures. However, the presently disclosed mapping system and other aspects of the systems and methods provide feedback on the extent of cellular damage resulting from ablation and positively verify the integrity of the lesion focus. Thus, the presently disclosed embodiments, inter alia, address the lack of lesion quality feedback of today's known techniques by providing lesion visualization and lesion depth information to the physician while the procedure is being performed.

1A and 1B, the ablation visualization system (ablation visualization system, AVS) of the present disclosure may include: a light source 130A (such as a UV laser) outside the patient's body, and an optical device or optical device for delivering light from the light source into the patient's body. delivery fiber optic 130B; a camera 135A with appropriate filtering (where required) and an image bundle 135B connected to the camera; and one or more displays 140A with image processing software on its processor or controller Computer system 140 (for technicians) and 140B (for physicians).

As an example, FIG. 1C shows a diagram of a typical processing structure that may be used in conjunction with the methods and systems of the present disclosure. Computer processing device 200 may be coupled to display 212 for graphical output. Processor 202 may be a computer processor 204 capable of executing software. A typical example would be a computer processor such as or processor), ASIC, microprocessor, etc. Processor 204 may be coupled to memory 206 , which may typically be volatile RAM memory for storing instructions and data while processor 204 executes. The processor 204 may also be coupled to a storage device 208, which may be a non-volatile storage medium such as a hard drive, flash drive, tape drive, DVDROM, or similar device. Although not shown, computer processing device 200 typically includes various forms of input and output. I/O may include network adapters, USB adapters, Bluetooth radios, mice, keyboards, touchpads, displays, touchscreens, LEDs, vibrating devices, speakers, microphones, sensors, or any other input or output device. Processor 204 may also be coupled to other types of computer-readable media, including but not limited to electronic, optical, magnetic, or other storage or transmission devices capable of providing computer-readable instructions to a processor (eg, processor 204). Various other forms of computer-readable media can transmit instructions to or carry instructions to the computer, including routers, private or public networks, or other transmission devices or channels, wired or wireless. Instructions may include code from any computer programming language including, for example, C, C++, C#, Visual Basic, Java, Python, Perl, and JavaScript.

Program 210 may be a computer program or computer readable code comprising instructions and/or data, and may be stored on storage device 208 . Instructions may include code from any computer programming language including, for example, C, C++, C#, Visual Basic, Java, Python, Perl, and JavaScript. Generally, processor 204 may load some or all of the instructions and/or data of program 210 into memory 206 for execution. Program 210 may be any computer program or process, including but not limited to web browser 166, browser application 164, address registration process 156, application 142, or any other computer application or process. Program 210 may include various instructions and subroutines that, when loaded into memory 206 and executed by processor 204, cause processor 204 to perform various operations, some or all of which may implement Methods disclosed herein for managing medical care. Program 210 may be stored on any type of non-transitory computer readable medium such as but not limited to a hard drive, removable drive, CD, DVD, or any other type of computer readable medium.

It is possible that the light source 130A may include a cart 132 . In some embodiments, the system may also include a dedicated catheter 105A that includes an inflatable balloon 105B. In some embodiments, the image bundle 135B and light delivery optical fiber may extend from the exterior of the catheter to the distal region of the catheter inside the balloon 105B. It is contemplated that there may be multiple components added to each part of the systems disclosed above. The system may also include a guide wire for the catheter 105C, an EP fluoroscopy system 160, a steerable sheath 165A, a guide wire for the steerable sheath 165B, an introducer sheath kit 165C , a balloon inflator (indeflator) 170 and a transseptal set 180.

FIG. 1B is a block diagram of an example system according to the present disclosure. The AVS system includes an external instrumentation 125 with a light source 130A, a camera 135A with appropriate filtering as needed, and a computer system (not shown) with one or more displays 140A and image processing software. The AVS system includes internal instrumentation including an ablation device 140, an illumination device 130B, and an imaging device 135B, wherein the internal components are within an internal balloon 105B associated with the catheter 105A. It should be noted that the internal instrument comprising the catheter 105A and the inflatable balloon catheter 105B is coupled to the external instrument 125 . In some embodiments, illumination device 130B and imaging device 135B may utilize fiber optic waveguides to deliver light to and from the treated tissue.

Still referring to FIGS. 1A and 1B , the light source 130A may include a laser as an illumination source for the myocardium. The output wavelength of the laser can be within the absorption range of the target fluorophore (in this case, NADH) in order to induce fluorescence in healthy cardiomyocytes. In some embodiments, the laser can be a UV laser.

According to some aspects of FIGS. 1A and 1B , laser-generated UV light can provide more irradiation power and its wavelength can be purified at any number of nanometers that may be desired. Emissions at more than one wavelength can be problematic in that they can cause other molecules to fluoresce (instead of NADH), and they can cause reflections in the reflection range to inject image noise or worse, overwhelming the NADH reflection signal. Commercial lasers exist that can emit in the desired wavelength band of illumination and can be used at many power settings approaching 50 to 200 mW or higher. In some embodiments, the instant system uses a laser with adjustable power up to 150 mW.

The wavelength range on the illumination source can be defined by the anatomy of interest, in particular choosing wavelengths that result in maximal NADH fluorescence rather than too much collagen fluorescence activated by only slightly longer wavelengths. In some embodiments, the laser light has a wavelength of 300nm to 400nm. In some embodiments, the laser light has a wavelength of 330nm to 370nm. In some embodiments, the laser light has a wavelength of 330nm to 355nm. In some embodiments, 355nm can be used because it is adjacent to the peak sum of NADH excitation and just below collagen excitation. The output power of the laser can be high enough to produce recoverable fluorescence data, but not so high as to cause cell damage.

Still referring to FIGS. 1A and 1B , catheter 105A may be employed to perform a number of functions including, but not limited to, vessel navigation, blood replacement, propagation of light from light source 130A to the myocardium, and image acquisition of fluorescence. An example of a suitable catheter is disclosed in commonly owned US Application No. 13/624,902, which is incorporated herein in its entirety. In some embodiments, ablation techniques are housed or integrated within the system and catheter embodiments.

2 and 3, the catheter 105A may contain a balloon 105B at or near the distal end of the catheter 105A. Balloon 105B can displace blood from the surface of the myocardium due to the absorption of radiation and fluorescence wavelengths by blood. To do so, balloon 105B may be inflatable and compliant to position well within the anatomy, particularly the pulmonary vein. The medium used to inflate the balloon 105B may also be optically transparent, but is desirably fluorescently opaque for navigation purposes. Suitable aerating media include, but are not limited to, deuterium (heavy water) and _CO2 , which meet both requirements. Balloon 105B may also be made of a material that is optically transparent at least at the wavelengths of interest for both myocardial illumination and fluorescence. The balloon 105B may be made of a non-compliant material with an optimal variable size that best fits the pulmonary veins and other structures, or a compliant material such as silicone or urethane. In some embodiments, balloon 105B may be optically transparent in the UV range of 330nm to 370nm.

In some embodiments, balloon 105B is optically transparent to UV radiation from 330 nm to 370 nm and to fluorescent wavelengths from 400 nm to 500 nm. Suitable UV transparent materials for the balloon include, but are not limited to, silicone and urethane.

Still referring to FIGS. 2 and 3 , catheter 105A can also be used to efficiently deliver illumination light (eg, UV laser and optionally white light) from an external light source to balloon 105B and out of balloon 105B to the myocardium. In some embodiments, laser delivery fibers, typically made of quartz, can be used to deliver illumination light from a UV laser source due to quartz's UV efficiency and small diameter.

The catheters of FIGS. 2 and 3 can also be used to collect and transmit light of NADH fluorescence from illuminated tissue to an external camera (see FIGS. 1A and 1B ). In some embodiments, this can be accomplished via an imaging fiber optic bundle extending from the distal region of the catheter to an external camera (see FIG. 1A ). In some embodiments, the image bundle may contain one or more of the individual single-mode fibers that together maintain image integrity while transmitting the image along the length of the catheter to the camera and filter as desired. Despite being flexible and small in diameter, the imaging bundle can achieve a sufficient field of view to image the target tissue area covered by the balloon.

The camera can be connected to a computer system (see FIG. 1A ) for viewing and can have a high quantum efficiency at a wavelength corresponding to NADH fluorescence. One such camera is the Andor iXon DV860. A 435nm to 485nm (460nm in some embodiments) optical bandpass filter can be inserted between the imaging beam and the camera to block light outside the NADH fluorescence emitting segment. In some embodiments, additional optical bandpass filters can be inserted between the imaging beam and the camera to block light outside of NADH fluorescence emitting segments selected based on the peak fluorescence of the tissue being imaged.

In some embodiments, the digital images produced by the camera are used to perform 2D and 3D reconstructions. In some embodiments, the image beam can be connected to a camera that can generate a digital image from NADH fluorescence (fNADH) that can be displayed on a computer. The computer processor/controller has data on the pixel intensities of the pixels used to form the digital image, so the computer processor/controller can use a 2D or 3D program to generate a depth correlation map. In some embodiments, NADH fluorescence can be communicated directly to a computer processor/controller.

Referring to Figure 4A, the operation of the system of the present disclosure is illustrated. Initially, (step 410 ) a catheter is inserted into an area of cardiac tissue affected by atrial fibrillation, such as the pulmonary vein/left atrium junction or another area of the heart. For example, blood is removed from the field of view by a balloon. For atrial fibrillation ablation, a transparent balloon around a fiber optic waveguide can be used to displace blood at the pulmonary vein/left atrium junction. The affected area may be irradiated with ultraviolet light from a light source and fiber optic or another irradiating device (step 415). The ablation device may be used to ablate tissue in the irradiated region either before or after irradiation (step 420). Using the system of the present disclosure, point-to-point RF ablation or cryo or laser or other known ablation procedures may be employed. Ablation is performed by passing the tip across the lumen of the catheter or outside of the catheter. After the procedure, the ablation tip can be withdrawn. In some embodiments, ablation tips may be incorporated into the catheters disclosed herein.

Still referring to FIG. 4A , the illuminated area is imaged (step 425 ) by the combination of the imaging beam and the camera. In some embodiments, the methods of the present disclosure rely on fluorescence emission imaging of NADH, which is the reduced form of nicotinamide adenine dinucleotide (NAD+). NAD+ is a coenzyme that plays an important role in the aerobic metabolic redox reactions of all living cells. It acts as an oxidant by accepting electron oxidants from the citric acid cycle (tricarboxylic acid cycle), which occurs in the mitochondria. Through this process, NAD+ is thus reduced to NADH. NADH and NAD+ are most abundant in the mitochondria, the respiratory unit of the cell, but are also found in the cytoplasm. NADH is an electron and proton donor in mitochondria to regulate cellular metabolism and is involved in many biological processes, including DNA repair and transcription.

By measuring the tissue's UV-induced fluorescence, it is possible to understand the biochemical state of the tissue. NADH fluorescence has been studied for its use in monitoring the metabolic activity and cell death of cells. Several studies in vitro and in vivo investigated the potential of using the fluorescence intensity of NADH as an intrinsic biomarker for cell death (apoptosis or necrosis) monitoring. When NADH is released from the mitochondria of damaged cells or converted to its oxidized form (NAD+), its fluorescence drops dramatically, making it very useful for distinguishing healthy tissue from damaged tissue. During the ischemic state when oxygen is not available, NADH can accumulate in cells, resulting in increased fluorescence intensity. However, in the case of dead cells, NADH is present and disappears together. The table below summarizes the different states of relative intensity due to NADH fluorescence:

Still referring to FIG. 4A , while both NAD+ and NADH absorb UV light fairly readily, NADH autofluoresces in response to UV excitation while NAD+ does not. NADH has a UV excitation peak at about 350 nm to 360 nm and an emission peak at about 460 nm. In some embodiments, methods of the present disclosure may use excitation wavelengths of about 330 nm to about 370 nm. Thus with the appropriate instrumentation, emission wavelengths can be imaged while measuring hypoxic and necrotic tissue in the region of interest in real time. In addition, relative metrics can be achieved using gray scale rendering scales of NADH fluorescence.

Under hypoxic conditions, oxygen levels drop. The intensity of the fNADH emission signal can then increase, indicating an excess of mitochondrial NADH. If hypoxia is not detected, attenuation of the signal eventually occurs when the affected cell dies along with its mitochondria. The high contrast of NADH levels can be used to identify the periphery of end-stage damaged ablated tissue.

Still referring to FIG. 4A , to initiate fluoroscopic imaging, the operator may deploy a balloon mounted on the distal portion of the catheter. Next, NADH is excited by UV light from a light source such as a UV laser. NADH in tissue samples absorbs light at the excitation wavelength and emits light at longer wavelengths. The emitted light can be collected and passed back to the camera, and a display of the imaged illuminated region can be produced on a display (step 430), which is used to identify ablated and non-ablated tissue in the imaged region using NADH fluorescence (step 435) . Then, if additional tissue needs to be ablated, the process can be repeated by returning to the ablation step. It should be appreciated that while FIG. 4A illustrates steps performed sequentially; many of these steps may be performed at or near the same time, or in a different order than that shown in FIG. 4A. For example, ablation, imaging, and display can occur simultaneously, and identification of ablated and non-ablated tissue can occur while the tissue is being ablated.

Application software executed on the computer system by the processor or computer can provide the user with an interface with the physician. Some of the main functions may include: laser control, camera control, image capture, image adjustment (brightness and contrast adjustment, etc.), lesion identification, lesion depth analysis, process event recording, and file manipulation (create, edit, delete, etc.) ).

FIG. 4B illustrates a flowchart of the process of determining the lesion depth. Step 440 discloses using NADH fluorescence from a computer display via application software to identify ablated and non-ablated tissue in the imaged region. Step 445 discloses the identification of lesion specific images of interest to begin lesion depth analysis. Step 450 discloses identifying healthy tissue regions within the image of the lesion of interest. By way of a non-limiting example, referring to Figures 6A and 6B, imaging fluorescence of NADH in the heart can yield: a physiological display of lesion sites with a dark appearance due to lack of fluorescence; gaps with a bright appearance due to normal fluorescence and any ischemic tissue with a brighter halo-like appearance near the lesion site (see Figures 6A and 6B). When a lesion was identified, it was selected for lesion depth analysis.

Step 455 discloses normalizing the entire image using the ratio of the NADH fluorescence intensity observed at each pixel to the NADH fluorescence intensity observed in the identified healthy tissue. Step 460 discloses processing the resulting normalized image data via an algorithm derived from a pre-established data set relating the normalized intensity ratio to lesion depth. Lesion depth can be calculated using the ratio of the fluorescence of healthy tissue to the fluorescence of lesion tissue. First, the user identifies regions of healthy tissue within the image. The application software then normalizes the entire image using the ratio of the NADH fluorescence intensity observed at each pixel to the NADH fluorescence intensity observed in the identified healthy tissue. The resulting normalized image data is then processed via an algorithm derived from a pre-established data set relating the normalized intensity ratio to lesion depth. By using the patient's own myocardial NADH fluorescence as a control, the method greatly reduces the effects of interpatient absolute NADH fluorescence variation, as well as losses in the illuminating light and imaging system and variations in light intensity due to specular and diffuse reflection, and Other optical non-ideal properties.

Step 465 discloses performing a depth analysis along a single row across the lesion. It is also possible to perform in-depth analysis from information from a single location, row or region for a single location in the lesion. Figures 4C to 4F show depth analysis along a single row. For example, Figure 4C shows an image of a canine heart that has been ablated six times. The square encloses a single ablation lesion. Shown in the upper right corner of Figure 4D is an NADH fluorescence (fNADH) image obtained from the same region of a blood-perfused canine heart. Figure 4E is a 2d depth map performed along a single row and generated based on the digital image in Figure 4D (ie from the pixel intensities forming the digital image). Figure 4F is a hematoxylin and eosin-stained canine heart tissue cut along the same line, showing the actual depth of the lesion (the squares show the boundaries of the lesion), where the deepest area corresponds to that in Figure 4D Darkest spot and lowest fNADH in Figure 4E.

Step 470 discloses repeating steps 460 to 470 along different rows parallel to the initial row, so that the depth data of each row is compiled into a 3D reconstructed model of the lesion site. The process of depth analysis along a single row across the lesion can be repeated multiple times along different rows than the initial row, and the depth data of each row can be compiled into a 3D reconstruction model of the lesion site.

By way of non-limiting example, Figure 4G shows a digital image of two ablation lesions and the space between lesions imaged by fNADH. Figure 4H shows the 3D reconstruction from the pixel intensities in the digital image of Figure 4G. As mentioned above, both 2D and 3D data can be used for further diagnosis or treatment.

The intensity of the fluorescence detected by the camera can be measured and plotted, where the lowest fluorescence (darkest) corresponds to the deepest lesion and the highest fluorescence (brightest) corresponds to non-ablated or healthy tissue. Any gray level between the light and dark extremes generally corresponds to the degree of depth of the tissue lesion. The sensitivity of the camera sensor determines the number of gray levels between full black and full white. Several binary numbers are common in such applications, including 256 levels and 65,536 levels corresponding to 8-bit and 16-bit resolutions, respectively. With 8 bit sensitivity, 0 would be completely black and 255 would be completely white, with 254 gray levels in between. Using this grayscale image, an appropriate depth map can be estimated. In some embodiments, 24-bit resolution may also be used.

It should be noted that fNADH imaging can reliably and reproducibly predict cardiac ablation lesion diameter and depth. The loss of fNADH intensity correlated with the actual measured diameter and depth of multiple RF lesions, with correlation coefficients greater than 96% and 79%, respectively. Loss of correlation is possible at lesion depths greater than 2 mm because UV radiation cannot reliably penetrate cardiac tissue deeper than 2 mm. With further lesion depths, no further fNADH could be detected, and thus a reproducible plateau of fNADH signal intensity was observed at approximately 2 mm lesion depth. The average left atrial wall thickness at the site typically targeted for ablation of the left atrium was 1.85 mm as measured from the CT scan. Therefore, the nadir and plateau of fNADH signal intensity observed across RF lesions serves as a reasonable model for clear, all or none determination of sufficient lesion depth.

The methods, systems and devices disclosed herein can be used in a variety of therapeutic procedures. Exemplary procedures in which the methods, systems, and devices disclosed herein may be used include, but are not limited to, diagnostic and therapeutic procedures in the heart, for the treatment of cardiac arrhythmias (such as, for example, supraventricular arrhythmias and ventricular arrhythmias), For the treatment of atrial fibrillation, and for pulmonary vein mapping and ablation. The tissue ablated can be myocardium (epicardium or endomyocardium), but the methods disclosed herein should work equally well on skeletal muscle, liver, kidney, and other tissues with a significant presence of NADH-rich mitochondria.

The methods disclosed herein can be used with two-dimensional (2D) to three-dimensional (3D) mapping schemes. Multiple 2D images can be superimposed onto a 3D reconstructed image of a tissue or organ, including the heart. Many arrhythmia procedures include the use of reconstructed three-dimensional images of the patient's specific anatomy during the procedure. A variety of imaging modalities are used, including computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and electroanatomical mapping using systems such as NAVX and CARTO. In all cases, the three-dimensional anatomical image or surface presents the patient-specific anatomy to help locate the tissue region to be treated. In all cases, the ability to visualize the precise location of lesion formation, as well as the precise location of lesion absence (eg, "gaps" or breaks in the concentration of lesions), will guide surgery to optimize treatment outcomes. 2D image to 3D image mapping allows the system to map single or multiple images of tissue (which may indicate damage) in a three-dimensional, rotatable, interactive virtual environment using the patient's specific anatomical presence or absence of foci).

In some embodiments, the systems and methods of the present disclosure enable registration and/or superimposition of images produced by the system to images using other imaging modalities such as MRI images, computed tomography (CT) images, ultrasound images, and three-dimensional reconstructions thereof. See the specific anatomy of the patient. In some embodiments, the systems and methods of the present disclosure may also include registering and/or superimposing images produced by the system to the patient as seen using other electroanatomical mapping, anatomical reconstruction, and navigation systems, such as NAVX and CARTO specific anatomical structures. Registration and overlay can be done in real-time during the surgical procedure. Texture mapping of the NADH image onto the reconstructed endocardial surface enables visualization of the treatment site. For example, multiple NADH snapshots of a lesion can create a complete panoramic image of the entire pulmonary vein ostium or multiple pulmonary veins. Placing a sensor on the catheter tip can provide information that allows the NADH images to be combined to create a 3D reconstructed image.

Examples of using the systems and methods of the present disclosure are provided below. These examples are representative only and should not be used to limit the scope of the present disclosure. Various alternative designs exist for the methods and devices disclosed herein. Accordingly, the embodiments were chosen primarily to demonstrate the principles of the devices and methods disclosed herein.

Example

Experiments were performed using a functionally equivalent system to generate ablated lesions and lesion images to develop methods for lesion depth analysis. The experimental setup is described below.

The NADH fluorescence system was provided to illuminate the epicardial surface using an LED spotlight (PLS-0365-030-07-S, Mightex Systems) with a peak wavelength of 365 nm. Emitted light was bandpass filtered at 460nm +/- 25nm and imaged using a CCD camera (Andor Ixon DV860) fitted with a low magnification lens. Fluorescence of NADH (fNADH) was imaged to monitor the status of epicardial tissue.

The RFA system provides RFA using a standard clinical RF generator (EPT 1000 Ablation System from Boston Scientific). The generator was electrically connected to the animal via a 4mm cooled Blazer ablation catheter (Boston Scientific) to deliver the lesion. Use grounding pads during ablation. The generator is set to temperature control mode. Cryoablation is performed using a custom metal probe immersed in liquid nitrogen or by using Medtronic's Freezor MAX Cardiac Cryoablation Catheter.

Referring to FIGS. 5A and 5B , first, baseline data of NADH excitation and emission spectra in healthy heart tissue were obtained. 5A and 5B show tissue excitation-emission matrices. Due to the presence of NADH, healthy tissue emits strongly at 450nm to 470nm when excited in the range of 330nm to 370nm. There is no large peak associated with NADH in ablated tissue.

An example of a typical RFA lesion is shown in Figures 6A and 6B. The image on the left was captured using white light illumination, while the fNADH image on the right was captured using UV excitation with a 460 nm filter.

All animal protocols were reviewed and approved by the Animal Care and Use Committee of The George Washington University School of Medicine and conformed to the guidelines for animal research.

Ex vivo experiments were initially performed using excised, bloodless hearts of rats (200-300 g Sprague-Dawly). Animals were heparinized and anesthetized using standard procedures. The chest is opened using a midline incision. The heart was then excised; the aorta was cannulated and perfused ex vivo with Langendorff at constant pressure. The heart was placed on top of a grounding pad and submerged in Tyrode's solution at 37°C during RFA ablation. Alternatively, the cryoprobe is applied directly to the epicardial surface.

Radiofrequency energy was applied to the epicardium of resected, bloodless rat ventricles while varying the temperature and duration to generate RFA lesions of varying sizes. A uniform contact force of 2 grams is measured as measured by a calibrated balance. Lesions of different sizes were generated by varying the temperature (50, 60 and 70 degrees Celsius) and time (10, 20, 30, 40, 50 seconds) of RF application. A total of 12 RFA lesions were generated on six different rat heart specimens.

NADH fluorescence around the lesion and tissue was measured by illuminating the epicardial surface with UV light at 365 nm using a Mightex Precision LED spotlight. The light corresponding to fNADH was selected using a 460/25 nm bandpass filter and imaged using a high sensitivity charge-coupled device camera. Additionally, the lesion was imaged with bright light adjacent to the tape measure to enable measurement of lesion size. Then, the fNADH images were imported into ImageJ software to measure the size, and the dark spectrum of each lesion was analyzed. Darkness spectra were assessed by placing a linear region of interest (ROI) in the center of the ablation lesion imaged by each fNADH to measure pixel intensity at each point across the lesion perimeter. Then, the ventricular tissue was perfused retrogradely with Tyrode's solution containing triphenyltetrazolium chloride (TTC) to assess tissue necrosis. Epicardial lesions were resected for macroscopic and histological measurements of tissue damage.

In vivo experiments were performed using a canine open chest model. Animals underwent thoracotomy after induction of general anesthesia. Using a 4 mm radiofrequency ablation catheter, multiple lesions were induced on the epicardial surface at various durations and temperatures. The epicardial surface of the heart was then illuminated with UV light at 365 nm (Mightex precision LED spotlight) and the corresponding fNADH was passed through a 460/25 nm filter coupled to a high quantum efficiency fluorescence camera (Andor Ixon DV860 camera). Lesions were imaged under bright white light with a tape measure to measure lesion size.

Necropsy was provided after the rat experiments and the hearts of the animals were stained with TTC. TTC is a standard procedure used to assess acute necrosis, which depends on the ability of dehydrogenase and NADH to react with tetrazolium salts to form formazan pigments. Metabolically active tissue appears dark red and necrotic tissue appears white. Following TTC staining, lesions were bisected at the central linear ROI previously defined for pixel intensity analysis for measurement of lesion depth across the corresponding ROI. Lesion morphology, width, length, and depth were determined and recorded by visual inspection.

For canine experiments, segments of multiple epicardial lesions were bisected longitudinally and submitted for histological staining (hematoxylin-eosin). Specimens were then analyzed under light microscopy at 40X to characterize morphological changes for determining the extent of heat-induced cellular damage and necrosis.

Statistical analysis included lesion size measured by two independent readers by fNADH and TTC staining using the documented method and standard deviation. Correlation coefficients for lesion size by fNADH and by TTC staining were also obtained and recorded.

The results included that epicardial fNADH first correlated with lesion size. In a rat model, a total of 12 epicardial surface lesions were delivered and measured using fNADH and triphenyltetrazolium chloride (TTC) staining by two independent detectors (see Figure 7A, Figure 7B and Fig. 7C). A typical fNADH image is illustrated in Figure 7A, and actual lesion diameter measurements using TTC staining are shown in Figure 7B. Linear measurements of lesion diameters using TTC (top image, 7A) were correlated with lesion diameters obtained from corresponding fNADH images (bottom image, 7B). Figure 7C shows a summary plot of lesion size versus number of ablation deliveries. For all lesion sizes, epicardial fNADH closely predicted actual lesion diameter as determined by TTC staining. The average diameters of NADH and TTC were 7.9±1.85mm and 8.2±1.95mm, respectively, and the correlation coefficient was 96%.

The temperature and number of lesion deliveries were varied to obtain a large number of epicardial surface lesions at varying depths in the rat heart. The intensity of epicardial fNADH was then measured multiple times along the centerline of the lesion. Example lesion groups are shown in Figures 8A, 8B, 8C and 8D, where fNADH is plotted in the top plot (Figure 8A) for the row spanning lesion #1 in Figure 8C. Figure 8B shows the measured depth obtained from a TTC-stained heart across the same lesion. Figure 8D shows the inverse image of fNADH used in the graph (Figure 8A). This was done so that the higher intensity of anti-fNADH correlates with the lesion depth shown and has a similar shape.

Referring to Figures 9 and 10, lesion depth was compared to anti-fNADH signal intensity, compiled and plotted in Figure 9. In addition, lesion foci were delivered at 50°C for 10 s, 20 s, 30 s, 40 s, and 50 s, respectively. The same comparison was obtained at varying temperatures and showed similar findings (see Figures 9 and 10).

Referring to FIG. 11 , linear correlation coefficients were obtained for different durations at a specific temperature using lesion foci obtained by varying the temperature and lesion focus duration. Figure 11 shows the results at 60 degrees Celsius, with correlation coefficients ranging from 0.84 to 0.97 depending on the duration of ablation.

A 3D reconstruction of lesion depth was obtained from canine epicardial images by aggregating the gray scale from the individual maps of fNADH using only 5 parallel rows across the lesion and plotting the values using a 3D mapping program.

Figures 12A and 12B, Figures 12C and 12D, and Figures 12E and 12F show higher resolution 3D reconstructions of cryo-lesions, radiofrequency lesions, and multiple cryo-lesions, respectively. Note that in maps showing multiple lesions, variations in lesion depth are visible.

Experimental results demonstrate that fNADH is an accurate measure of epicardial lesion size and a predictor of lesion depth. A 3D reconstruction of depth can be obtained by repeating the method described above along multiple lines across the ablation image and compiling the results (see Figures 10, 12A, 12B and 12C).

As noted above, Figure 13A shows an fNADH image of an ablation lesion created, for example, by using a cryoablation catheter, and Figure 13B is a magnified image of the ablation lesion. Fig. 13C shows a 3D depth reconstruction correlation map of the same ablation lesion. The main difference is that Figure 12 includes some ablation lesions created using RFA, where RFA and cryo lesions have different appearances in 3D.

Referring to Figure 14, RFA lesion foci can be detected and differentiated from visible tissue with excellent resolution because RFA lesion foci exhibit very low or undetectable fNADH compared to surrounding healthy myocardial tissue. Lesion diameter imaged by fNADH correlated closely with lesion size measured by TTC (mean NADH and TTC diameters were 7.9±1.85 mm and 8.2±1.95 mm, respectively; correlation coefficient [CC] 96%). The intensity of epicardial fNADH correlated inversely with the actual lesion depth measured by TTC analysis. As shown in Figure 14, this relationship was reproduced with a CC of over 79% for all RFA variables for lesion depths up to 1.8 mm (significance p<0.0001), beyond which the fNADH signal intensity became saturated and plateaued.

The relationship between lesion depth and epicardial fNADH was reproduced with statistical significance. Multiple lesions of different sizes were generated on the epicardium of rat ventricles by varying RF duration and temperature. The lesion depth and anti-fNADH signal intensity were analyzed for these multiple lesions. Loss of fNADH intensity correlated with lesion depth with a Pearson correlation coefficient of 78% and was highly significant (p<0.0001) up to a lesion depth of approximately 2 mm. Beyond 2 mm, the relationship loses its significance as fNADH values plateau.

In some embodiments, a system for imaging ablated tissue and non-ablated tissue comprises an ultraviolet (UV) laser light source; an inflatable balloon catheter comprising a UV laser guide and an image guide; coupled to the catheter an external fluorescence camera; a computer with a display coupled to the camera; and imaging software.

In some embodiments, the catheter also includes a guidewire port for catheter navigation; and/or ablation therapy techniques, including radiofrequency electrodes, laser ablation capabilities, or cryoablation capabilities. In some embodiments, the balloon may be made of a compliant material such as silicone or urethane; optionally transparent in the UV range of 330nm to 370nm; or optionally transparent in the fluorescent light range of 430nm to 490nm .

In some embodiments, a method of estimating the depth of a lesion may include the steps of: acquiring and displaying nicotinamide adenine dinucleotide hydrogen (NADH) fluorescence data of tissue; identifying regions of healthy tissue within the image; The ratio of the NADH fluorescence intensity observed at each pixel to the NADH fluorescence intensity observed in the identified healthy tissue is used to normalize the entire image; to identify regions of the ablated tissue; and to apply the resulting normalized Algorithm for correlation between image and lesion depth.

In some embodiments, the correlation algorithm uses the data and then uses a pre-established data set that correlates the normalized intensity ratio to lesion depth. In some embodiments, lesion depth estimation uses the patient's own myocardial NADH fluorescence as a control. In some embodiments, ablation is performed using one or more of the following techniques: radiofrequency ablation, laser ablation, or cryoablation. The tissue can be cardiac tissue. In some embodiments, cross-sectional mapping of the estimated lesion depth is performed along the line indicated by the user. In some embodiments, 3D mapping of the estimated lesion depth is performed by compiling a series of cross-sectional views.

In some embodiments, there is provided a method of treating atrial fibrillation, the method comprising: acquiring and displaying NADH fluorescence data in a specific region of cardiac tissue (such as the foramen of the pulmonary veins); analyzing lesion depth across the images; identifying a healthy heart tissue; identification of appropriate lesion; identification of incomplete lesion, if present; identification of ischemic area (injured but not necrotic tissue), if present; reapplying ablation therapy where needed or to fill lesion The identified gaps in the heart, either to complete the incomplete lesion, or to bridge the ischemic area; repeat the above steps as needed to recover and reveal the repaired tissue; and for other regions of the heart (such as the remaining Repeat the above steps for the pulmonary veins, other parts of the left atrium, or even specific regions of the right atrium including the superior vena cava).

In some embodiments, a catheter having a proximal end and a distal end for imaging ablated epicardial cardiac muscle tissue, the non-ablated space at the pulmonary vein/left atrium junction, and lesion depth comprises: an inflatable Transparent compliant or non-compliant balloon made of UV-transparent material filled with a transparent fluid capable of transmitting light, used to displace surrounding blood to allow visualization of NADH fluorescence at the distal end; UV irradiation A device for exciting mitochondrial NADH in pulmonary vein and left atrium tissue at the distal end using an optical fiber capable of transmitting UV light; a microfiberscope for detecting NADH fluorescence from irradiated pulmonary vein and left atrium tissue at the distal end; A fluorescence camera at the proximal end coupled to the microfiberscope for creating images from the detected NADH fluorescence, the fluorescence camera includes a 460nm +/- 25nm bandpass filter to detect light from the NADH fluorescence of irradiated pulmonary vein and left atrium tissue, where the detected fluorescence data show the physiology of the lesion site with a dark appearance due to lack of fluorescence, the physiology of the gap with a bright appearance due to normal fluorescence, and the physiology at the lesion site Physiology of any ischemic tissue surrounding the site with a bright halo-like appearance; and a module for determining the depth of the lesion along a line spanning the length of the lesion by plotting the detected fluorescence intensity along the line ; where the lowest measured fluorescence intensity corresponds to the deepest point at the lesion site, while the highest fluorescence corresponds to non-ablated tissue.

In some embodiments, the module applies a gray scale of pixels ranging from all black to all white to create a 2D map of the depth of the lesion along the row, where assuming 256 (0 to 255) gray levels , 0 is all black and is the deepest point, and 255 is all white and is the shallowest point, where the 2D map of the depth of the ablated tissue is an absolute measurement, where the fNADH signal intensity is normalized to the previously established fNADH/depth gray scale value.

In some embodiments, the 2D map of the depth of the ablated tissue is repeated multiple times along a vertical line across the width of the lesion, each 2D map of the depth is parallel to the row along the length of the lesion, and the integration of the vertical lines Each of the 2D maps on the depth of ablated tissue is reconstructed as a 3D image of the depth of ablated tissue.

In some embodiments, the catheter also includes a guidewire lumen for insertion of a flexible guidewire. The camera may be a CCD camera with high quantum efficiency. In some embodiments, the fiberscope is an optical imaging bundle. In some embodiments, UV irradiation is provided by a laser source at 330nm to 370nm, and more specifically at 335nm. In some embodiments, the tip of the UV irradiating fiber is covered with a diverging lens to refract and disperse the UV light.

In some embodiments, a method for acquiring real-time images of ablated endocardial cardiac muscle tissue, the non-ablated space at the junction of the pulmonary veins and the left atrium, and the depth of the lesion comprises: an inflatable transparent compliant balloon, the Balloon made of UV-transparent material filled with a light-transmitting clear fluid used to displace surrounding blood to allow visualization of NADH fluorescence at the distal end; irradiated with UV light for excitation of the pulmonary veins and left atrium Mitochondrial NADH of tissue; detection of NADH fluorescence from irradiated pulmonary vein and left atrium tissue using an optical imaging beam; image creation using a fluorescence camera by filtering the detected NADH fluorescence using a 460 nm bandpass filter; The detected fluorescence data show the physiology of the lesion site with a dark appearance due to lack of fluorescence, the physiology of the gap with a bright appearance due to normal fluorescence, and any defects around the lesion site with a brighter halo-like appearance. Physiology of blood tissue; and a module for determining lesion depth along a line by plotting the detected fluorescence intensity along the line across the length of the lesion; wherein the lowest fluorescence intensity measurement corresponds to the lesion The deepest point at the lesion site, while the highest fluorescence corresponds to non-ablated tissue. In some embodiments, the module applies a gray scale of pixels ranging from all black to all white to create a 2D map of the depth of the lesion along the row, where assuming 256 (0 to 255) gray levels , 0 is all black and is the deepest point, and 255 is all white and is the shallowest point, where the 2D map of the depth of the ablated tissue is an absolute measurement, where the fNADH signal intensity is normalized to the previously established fNADH/depth gray scale value. In some embodiments, the 2D map of ablated tissue depth is repeated multiple times along a vertical line across the width of the lesion site, each 2D map of depth is parallel to a row along the length of the lesion, and the ablation on the vertical line is integrated Each of the 2D maps of the tissue depth to reconstruct a 3D image of the depth of the ablated tissue. In some embodiments, irradiating, imaging, and generating occur while tissue is ablated using radiofrequency, cryoablation, or laser catheters. In some embodiments, illumination and imaging are performed using a fiber optic waveguide coupled to the tip of the lumen catheter that delivers ultraviolet light from the ultraviolet light source to the irradiated tissue. In some embodiments, the ablation is performed by using one of a radiofrequency catheter, a cryoablation catheter, or a laser ablation catheter.

In some embodiments, the system comprises: a catheter having a distal end and a proximal end for imaging ablated pulmonary vein and left atrial cardiac tissue and non-ablated space, the catheter comprising an inflatable compliant or A non-compliant balloon for displacing surrounding blood to allow visualization of NADH fluorescence at the distal end; an ultraviolet irradiation device for illuminating tissue at the distal end; and a microfiberscope for detection at the distal end Irradiated tissue; a fluorescence camera coupled to the microfiberscope at the proximal end for creating a 2D image, the fluorescence camera comprising a filter configured to pass ultraviolet radiation from the irradiated tissue captured by the microfiberscope ; where the detected 2D image shows the lesion site with a dark appearance due to lack of fluorescence, a gap with a bright appearance due to normal fluorescence, and any ischemic tissue with a brighter halo-like appearance around the lesion site ; an ablation device for ablating cardiac tissue at a distal end based on the detected 2D image; A module of the depth of the lesion site; where the lowest fluorescence intensity measurement corresponds to the deepest point of the lesion site, and the highest fluorescence corresponds to non-ablated tissue. In some embodiments, the module applies pixel gray scales ranging from full black to full white to create a 2D map of lesion site depth along a row, where assuming 256 (0 to 255) gray levels, 0 is completely black and is the darkest point, while 255 is completely white and is the lightest point. Here, the 2D map of the depth of ablated tissue is an absolute measurement, where the fNADH signal intensity is normalized to a previously established fNADH/depth gray scale value. In some embodiments, the 2D map of the depth of the ablated tissue is repeated multiple times along a vertical line across the width of the lesion, each 2D map of the depth is parallel to the row along the length of the lesion, and the integration of the vertical lines Each of the 2D maps of the depth of the tissue is ablated, thereby reconstructing a 3D image of the depth of the ablated tissue. In some embodiments, a display coupled to the external camera shows the detected 2D image. In some embodiments, the ablation device is an ablation catheter having a proximal end and a distal end. In some embodiments, the ablation catheter is a laser delivery catheter, a radiofrequency delivery catheter, or a cryoablation catheter.

In some embodiments, a catheter having a proximal end and a distal end for imaging ablated epicardial cardiac muscle tissue and a non-ablated space comprises: an ultraviolet irradiation device for exciting mitochondria of epicardial cardiac muscle tissue NADH; a fiberscope that detects NADH fluorescence from irradiated epicardial heart tissue at the distal end; a fluorescence camera coupled to the fiberscope at the proximal end for creating images from the detected NADH fluorescence, The fluorescence camera contained a 460 nm bandpass filter to detect NADH fluorescence captured by the microfiberscope; where the detected 2D images showed lesion sites with a dark appearance due to lack of fluorescence, and bright with normal fluorescence. The gap in appearance, as well as any ischemic tissue with a brighter halo-like appearance around the lesion site, was used to determine the intensity along the line by plotting the detected and measured fluorescence intensity along the line across the length of the lesion site. A module of lesion depth; where the lowest fluorescence intensity measurement corresponds to the deepest point of the lesion, and the highest fluorescence corresponds to non-ablated tissue. In some embodiments, the module applies a gray scale of pixels ranging from all black to all white to create a 2D map of the depth of the lesion along the row, where assuming 256 (0 to 255) gray levels , 0 is completely black and is the darkest point, and 255 is completely white and is the lightest point. Here, the 2D map of the depth of ablated tissue is an absolute measurement, where the fNADH signal intensity is normalized to a previously established fNADH/depth gray scale value. In some embodiments, the 2D map of the depth of ablated tissue is repeated on a vertical line across the width of the lesion site, the 2D map is parallel to the line along the length of the lesion, and each of the depths of ablated tissue on the vertical line is integrated. , thereby reconstructing a 3D image of the depth of the ablated tissue.

In some embodiments, a catheter having a proximal end and a distal end for imaging ablated epicardial heart muscle tissue and a non-ablated space comprises: an ultraviolet irradiation device for exciting the epicardial heart at the distal end Mitochondrial NADH of muscle tissue; a fluorescence camera located at the distal end for creating images from the detected NADH fluorescence that contains a 460nm bandpass filter to detect NADH fluorescence from irradiated epicardial cardiac muscle tissue where the detected fluorescence data show the physiology of a lesion site with a dark appearance due to lack of fluorescence, a gap with a bright appearance due to normal fluorescence, and a lesion site with a brighter halo-like appearance around the lesion site the physiology of any ischemic tissue; and a module for determining the depth of the lesion site along a line by plotting the detected and measured fluorescence intensities along the line across the length of the lesion site; wherein the lowest fluorescence intensity measurement Corresponds to the deepest point at the lesion site, while the highest fluorescence corresponds to non-ablated tissue. In some embodiments, the module applies pixel gray scales ranging from full black to full white to create a 2D map of lesion site depth along a row, where assuming 256 (0 to 255) gray levels , 0 is completely black and is the darkest point, and 255 is completely white and is the lightest point. Here, the 2D map of the depth of ablated tissue is an absolute measurement, where the fNADH signal intensity is normalized to a previously established fNADH/depth gray scale value. In some embodiments, the 2D map of the depth of ablated tissue is repeated on a vertical line across the width of the lesion site, the 2D map is parallel to the line along the length of the lesion, and each depth of ablated tissue is integrated on the vertical line. of each, thereby reconstructing a 3D image of the depth of the ablated tissue.

As described above, the present systems and methods provide high quality and verifiable lesion lesions, which can be at least one aspect of the success of the ablation procedure and the avoidance of recurrence. Mass lesion foci can be of appropriate depth and cause cellular necrosis (ie, transmural) completely from the endocardial surface to the epicardial surface of the heart while minimizing damage to distant non-cardiac structures. The presently disclosed systems and methods provide feedback, such as the extent of cellular damage caused by ablation, and actually verify the integrity of the lesion focus. The presently disclosed embodiments overcome at least some of the known technical problems by addressing the lack of lesion quality feedback by providing lesion visualization and lesion depth information to the physician during the procedure. This information should prove useful in creating and verifying appropriate lesions, reducing fluoroscopy time, and reducing the rate at which arrhythmias occur, thereby improving outcomes and reducing costs.

According to embodiments of the present disclosure, systems and methods provide real-time direct visualization of lesion foci and spaces during ablation using NADH fluorescence. The presently disclosed systems and methods function by detecting the fluorescence contrast between non-viable ablated myocardium and viable myocardium. The present disclosure provides the physician with lesion depth information in real time during the procedure.

According to some aspects of the present disclosure, the disclosed systems and methods can be used to determine lesion depth based on pixel intensities obtained after tissue is ablated and imaged using an fNADH system. An assessment of the depth of the ablation lesion can be provided by correlating the image intensity provided by the fNADH system with the depth of the lesion. This means that the relevant depth data can be integrated in the 3D reconstruction of the lesion, giving the physician real-time feedback on lesion geometry and quality.

According to some aspects of the present disclosure, there is provided a method for determining the depth of a lesion, the method comprising: irradiating cardiac tissue having a lesion; The tissue acquires mitochondrial nicotinamide adenine dinucleotide hydrogen (NADH) fluorescence intensity; creates a 2-dimensional (2D) map of the depth of the lesion site along the first row based on the NADH fluorescence intensity; and determines from the 2D map along The depth of the lesion site at selected points in the first row, where lower NADH fluorescence intensity corresponds to greater depths in the lesion site and higher NADH fluorescence intensity corresponds to non-ablated tissue.

In some embodiments, the method further comprises creating a lesion site in cardiac tissue by ablating. The obtaining step may include: detecting NADH fluorescence from the irradiated tissue; creating a digital image of the lesion site from the NADH fluorescence, the digital image comprising a plurality of pixels; and determining a plurality of pixels along a line across the lesion site NADH fluorescence intensity. In some embodiments, the method may further comprise distinguishing the lesion site from healthy tissue in the digital image based on the amount of NADH fluorescence from the lesion site and healthy tissue; Digital images were normalized.

In some embodiments, the detecting step includes filtering NADH fluorescence through a bandpass filter at about 435 nm to 485 nm. In some embodiments, healthy tissue has a lighter appearance, while lesion sites have a darker appearance. The creating step may include plotting the NADH fluorescence intensity along a row across the lesion site to create a 2D map of the depth of the lesion site.

In some embodiments, the method further comprises: obtaining NADH fluorescence intensity from the irradiated cardiac tissue along a second row across the lesion site; creating an index of the depth of the lesion site along the second row based on the NADH fluorescence intensity 2D map; a 3-dimensional (3D) image of the lesion site is constructed from the 2D map along the first row and the 2D map along the second row. In some embodiments, the obtaining, creating, and determining steps may be repeated multiple times along a vertical line across the width of the lesion, with each 2D map of depth parallel to the first row along the length of the lesion; and integrating vertical Each of the 2D maps of the depth of the lesion on the line to reconstruct a 3D image of the depth of the lesion.

The determining step may include applying a pixel grayscale ranging from completely black to completely white. The method can be used to analyze epicardial tissue, endocardial tissue, atrial tissue, and ventricular tissue.

In some embodiments, the irradiating step includes irradiating the cardiac tissue with laser-generated UV light, wherein the laser-generated UV light may have a wavelength of about 300 nm to about 400 nm.

According to some aspects of the present disclosure, there is provided a system for imaging cardiac tissue, the system comprising: an irradiation device configured to irradiate tissue having a lesion site to stimulate nicotinamide adenine di nucleotide hydrogen (NADH); an imaging device configured to detect NADH fluorescence from irradiated tissue; and a controller in communication with the imaging device programmed to follow a first path across the lesion site Rows to obtain NADH fluorescence intensity from irradiated tissue; create a 2-dimensional (2D) map of the depth of the lesion site along the first row based on the NADH fluorescence intensity; and determine from the 2D map at selected points along the first row The depth of the lesion site, where lower NADH fluorescence intensity corresponds to a greater depth in the lesion site, while higher NADH fluorescence intensity corresponds to non-ablated tissue.

According to some aspects of the present disclosure, there is provided a system for imaging cardiac tissue comprising: a catheter having a distal region and a proximal region; a light source; an optical fiber extending from the light source to the distal region of the catheter to illuminate Tissue with a lesion site near the distal end of the catheter, thereby exciting nicotinamide adenine dinucleotide hydrogen (NADH) in mitochondria in said tissue; an image beam for detecting NADH fluorescence from irradiated tissue; connected to a camera of the image beam configured to receive NADH fluorescence from the irradiated tissue and generate a digital image of the irradiated tissue, the digital image comprising a plurality of pixels; and a controller in communication with the camera, the controller configured to determine from the digital image the NAHD fluorescence intensity of a plurality of pixels along a first row across the lesion, create a 2D map of the depth of the lesion along the first row based on the NADH fluorescence intensity, and based on the 2D map to determine the depth of the lesion site at selected points along the first row, where lower NADH fluorescence intensities correspond to greater depths in the lesion site and higher NADH fluorescence intensities correspond to non-ablated tissue .

Systems, catheters, and methods for treating atrial fibrillation (AF) are provided. Endogenous NADH in cardiac tissue was detected using a balloon-guided catheter equipped with a UV irradiation source and an optical fiber capable of transmitting UV, a fluorescence-capable camera coupled to the imaging beam, and an optical bandpass filter to detect NADH fluorescence. Fluorescence (fNADH) was imaged to identify ablated and non-ablated regions. Gaps between ablated regions can be identified using fNADH imaging, which can then be ablated. The gray scale display of fNADH images is used to predict the depth of ablated lesions and additional lesions can be delivered at lesions of inappropriate width. Imaging can be performed during the ablation procedure and does not require additional chemicals such as contrast agents, tracers or dyes.

The foregoing disclosure has been set forth merely to illustrate various non-limiting embodiments of the present disclosure, and is not intended to be limiting. Since modifications to the disclosed embodiments incorporating the spirit and substance of the present disclosure may occur to those skilled in the art, the presently disclosed embodiments are to be construed as falling within the scope of the appended claims and their equivalents of everything.

Claims (23)

1., for the method determining the degree of depth at damage stove position, described method includes:

Irradiate the heart tissue with damage stove position；

Mitochondrion nicotinamide adenine two core is obtained from irradiated heart tissue along the first row striding across described damage stove position Thuja acid hydrogen (NADH) fluorescence intensity；

Create 2 dimension (2D) figures of the degree of depth at described damage stove position along described the first row based on described NADH fluorescence intensity； And

Being determined that the Chosen Point along described the first row damages the degree of depth at stove position by described 2D figure, the most relatively low NADH is glimmering Light intensity is corresponding to the bigger degree of depth in damage stove position, and higher NADH fluorescence intensity is corresponding to non-ablation tissue.

Method the most according to claim 1, it also includes by melting formation damage stove position in heart tissue.

Method the most according to any one of claim 1 to 2, wherein said acquisition step includes:

Detect the NADH fluorescence from irradiated tissue；

Created the digital picture at described damage stove position by described NADH fluorescence, described digital picture comprises multiple pixel；With And

Determine the NADH fluorescence intensity of the plurality of pixel along the described row striding across described damage stove position.

Method the most according to claim 3, it also includes:

Amount based on the described NADH fluorescence from described damage stove position and health tissues is distinguished in described digital picture Described damage stove position and described health tissues；

Described digital picture is normalized by NADH fluorescence intensity based on the pixel representing described health tissues.

Method the most according to any one of claim 1 to 4, wherein said detecting step includes by about 435nm extremely NADH fluorescence is filtered by the band pass filter of 485nm.

Method the most according to claim 4, wherein said health tissues has a brighter outward appearance, and described damage stove part There is dark outward appearance.

Method the most according to any one of claim 1 to 6, wherein said foundation step includes along striding across described damage The described row at stove position draws NADH fluorescence intensity, to create the 2D figure of the degree of depth at described damage stove position.

Method the most according to any one of claim 1 to 7, it also includes:

NADH fluorescence intensity is obtained from irradiated heart tissue along the second row striding across described damage stove position；

Create the 2D figure of the degree of depth at described damage stove position along described second row based on described NADH fluorescence intensity；And

By the 3-dimensional (3D) building described damage stove position along the 2D figure of described the first row and the 2D figure along described second row Image.

Method the most according to any one of claim 1 to 8, it also includes: along the width striding across described damage stove position The vertical line of degree is repeated several times described acquisition, creates and determine step, and each 2D figure of the described degree of depth is parallel to along described damage Hinder the described the first row of stove span access location length；And each in each 2D figure of described damage stove site depth on integration vertical line, To rebuild the 3D rendering of the degree of depth at described damage stove position.

Method the most according to any one of claim 1 to 9, wherein said determines that step includes that range of application is from completely black To the whitest pixel gray level.

11. methods according to any one of claim 1 to 10, wherein said heart tissue is selected from epicardial tissue, the heart Internal film tissue, atrial tissue and ventricular organization.

12. according to the method according to any one of claim 1 to 11, and wherein said irradiating step includes using laser instrument to produce UV light irradiate described heart tissue.

13. methods according to claim 12, the wavelength of the UV light that wherein said laser instrument produces is about 300nm to about 400nm。

14. for carrying out the system of imaging to heart tissue, and it comprises:

Irradiation unit, described irradiation unit is configured to irradiate and has the tissue at damage stove position to excite described tissue center line grain The nicotinamide adenine dinucleotide hydrogen (NADH) of body；

Imaging device, described imaging device is configured to detect the NADH fluorescence from irradiated tissue；With

Controller, described controller and described imaging device communication, program described controller with along striding across described damage stove portion The first row of position obtains NADH fluorescence intensity from irradiated heart tissue；Based on described NADH fluorescence intensity along described the first row Create 2 dimension (2D) figures of the degree of depth at described damage stove position；And determined the choosing along described the first row by described 2D figure Damaging the degree of depth at stove position at fixed point, the most relatively low NADH fluorescence intensity corresponds to the bigger degree of depth in damage stove position, and Higher NADH fluorescence intensity corresponds to non-ablation tissue.

15. systems according to claim 14, wherein said irradiation unit is UV laser instrument.

16. according to the system according to any one of claim 14 to 15, wherein said imaging device comprise photographing unit and from Described photographing unit extends to the fibrescope of the most irradiated tissue.

17. according to the system according to any one of claim 14 to 16, wherein said imaging device also comprise be arranged on described The band pass filter of the about 435nm to 485nm between photographing unit and described fibrescope.

18. according to the system according to any one of claim 14 to 17, the most also programs described controller and hangs oneself to detect Irradiate the described NADH fluorescence of tissue；The digital picture at described damage stove position, described numeral is created by described NADH fluorescence Image comprises multiple pixel；And determine that the NADH of the plurality of pixel along the described row striding across described damage stove position is glimmering Light intensity.

19. according to the system according to any one of claim 14 to 18, the most also programs described controller with along striding across The second row stating damage stove position obtains NADH fluorescence intensity from irradiated heart tissue；Based on described NADH fluorescence intensity along Described second row creates the 2D figure of the degree of depth at described damage stove position；And schemed and along institute by the 2D along described the first row State the 2D figure of the second row to build 3-dimensional (3D) image at described damage stove position.

20. according to the system according to any one of claim 14 to 19, the most also programs described controller with along striding across The vertical line of the width stating damage stove position is repeated several times this process, and each 2D figure of the described degree of depth is parallel to along described damage The described the first row of stove span access location length；And each in each 2D figure of described damage stove site depth on integration vertical line, with Rebuild the 3D rendering of the degree of depth at described damage stove position.

21. for carrying out the system of imaging to tissue, and it comprises:

Conduit, described conduit has remote area and proximal end region；

Light source；

Optical fiber, described optical fiber extends to the described remote area of described conduit from described light source, remote to irradiate near described conduit The tissue with damage stove position of end, thus excite the nicotinamide adenine dinucleotide hydrogen of described tissue Mitochondria (NADH)；

Image beams, described image beams is for detecting the NADH fluorescence from irradiated tissue；

Photographing unit, described photographing unit is connected to described image beams, and described photographing unit is configured to receive from irradiated tissue Described NADH fluorescence, and produce the digital picture of irradiated tissue, described digital picture comprises multiple pixel；With

Controller, described controller and described camera communications, described controller is configured to be determined by described digital picture NADH fluorescence intensity along the plurality of pixel of the first row striding across described damage stove position；Strong based on described NADH fluorescence Spend the 2D figure of the degree of depth creating described damage stove position along described the first row；And determined along described by described 2D figure Damaging the degree of depth at stove position described at the Chosen Point of the first row, the most relatively low NADH fluorescence intensity corresponds to described damage stove position In the bigger degree of depth, and higher NADH fluorescence intensity is corresponding to non-ablation tissue.

22. systems according to claim 21, the most also program described controller with along striding across described damage stove position The second row obtain NADH fluorescence intensity from irradiated heart tissue；Come along described second row based on described NADH fluorescence intensity Create the 2D figure of the degree of depth at described damage stove position；And schemed by the 2D along described the first row and along the 2D of described second row Figure builds 3-dimensional (3D) image at described damage stove position.

23. according to the system described in claim 21 or 22, the most also programs described controller with along striding across described damage stove The vertical line of the width at position is repeated several times this process, and each 2D figure of the described degree of depth is parallel to along described damage stove position long The described the first row of degree；And each in each 2D figure of described damage stove site depth on integration vertical line, described to rebuild The 3D rendering of the degree of depth at damage stove position.