MDCT

The ability of Minkowski Functionals to characterize local structure in different biological tissue types has been demonstrated in a variety of medical image processing tasks. We introduce anisotropic Minkowski Functionals (AMFs) as a novel variant that captures the inherent anisotropy of the underlying gray-level structures. To quantify the anisotropy characterized by our approach, we further introduce a method to compute a quantitative measure motivated by a technique utilized in MR diffusion tensor imaging, namely fractional anisotropy. We showcase the applicability of our method in the research context of characterizing the local structure properties of trabecular bone micro-architecture in the proximal femur as visualized on multi-detector CT. To this end, AMFs were computed locally for each pixel of ROIs extracted from the head, neck and trochanter regions. Fractional anisotropy was then used to quantify the local anisotropy of the trabecular structures found in these ROIs and to compare its distribution in different anatomical regions. Our results suggest a significantly greater concentration of anisotropic trabecular structures in the head and neck regions when compared to the trochanter region (p < 10-4). We also evaluated the ability of such AMFs to predict bone strength in the femoral head of proximal femur specimens obtained from 50 donors. Our results suggest that such AMFs, when used in conjunction with multi-regression models, can outperform more conventional features such as BMD in predicting failure load. We conclude that such anisotropic Minkowski Functionals can capture valuable information regarding directional attributes of local structure, which may be useful in a wide scope of biomedical imaging applications.

Research has been done by comparing radiation dose profile and image quality to single detector CT (SDCT) and multi detector CT (MDCT). The method of measuring dose accuracy and linearity of the output dose is done by placing a dose pencil on the iso center position in the middle of the gantry. The scanning parameters use axial mode with the acquisition factor of 120 kV, 25-250 mAs, 1 sec rotation time and 5-10 mm slice thickness. Head Phantom CTDI diameter of 16 cm is used for CT dose index (CTDI) measurement. These measurements use a routine head examination protocol provided by CT Scan. Evaluation of image quality using fantom Gammex ACR 464. The resulting data is normalized to obtain constant image noise between SDCT and MDCT. SDCT resulted in a linearity coefficient of radiation dose output ranging from 0.017 to 0.085 higher than MDCT ranging from 0.007 to 0.055. The accuracy of DOSIS radiation at 120 kV / 100 mAs from SDCT is 23.3 mGy and 31.2 mGy whereas MDCT ranges from 11.17-28.57 mGy. The standard deviation of radiation dose distribution pattern with CTDI head phantom ranged from 1.7 to 5.8. While the results of image quality measurement, linearity response to 5 standard materials indicate that they are within the range of HU reference values. Evaluation of homogeneity of CT number accuracy, uniformity of noise and uniformity of CT,center and CT,edge respectively are in the range-7 and + 7 HU, 0,258 and 1,123 HU and 0,93-3,85 HU. Contrast to Noise Ratio (CNR) measurements range from 1.03-2.72. In addition, the results of spatial resolution measurements range from 6-7 lp / cm. From the overall evaluation shows, that MDCT has a better score than a SDCT. However, when compared with standard reference values, a single CT detector can be retained as an imaging modality to support the patient's diagnostic process.

Computed Tomography Scanner (CT Scan) is one of the largest medical imaging technology discovery in the field of medical radiology. With the CT scan, an image of the inside of the human body tomography or transverse incision can be displayed, where the different density of each tissue is expressed in a scale from black to white (gray scale) based on attenuation values of each organ to X-ray radiation. CT technology development direction in the current issue are preferred to increase the speed of multi-slice imaging detector, image resolution enhancement, and reduction of the radiation dose received by the patient. The highest speed attained by DSCT technology that will directly correlate with patient dose reduction and the best resolution achieved with multi-slice detector technology combined with the focus moves to the X-ray tube.

Knowledge of the vascular anomalies has great importance in modern surgery, radiology and organ transplant procedures. The vascular variations may cause serious complications during these process. Multidetector computed tomography is an excellent imaging technique that it is a fast and non-invasive tool provides highly accurate and detailed evaluation of normal vascular anatomy and variants. In this study aimed to morphometric evaluation the celiac trunk and its branches of adults and investigate its possible variations using multidetector computed tomography. In the research 104 images was analyzed retrospectively who underwent abdominal multidetector computed tomography for various reasons in Necmettin Erbakan University Meram Medical Faculty Hospital. The mean age 62.5 ± 11.75 in males (n=52) in women 60 ± 10.1 (n=52) were identified as. Abdominal aorta, celiac trunk, splenic artery, common hepatic artery and left gastric artery diameter measurments were found large statistically significant at men compared with women (p<0.05) in our morphometric evaluation. The types of variation and the distribution was found in the following way: A normal celiac trunk formed from the splenic, common hepatic and left gastric arteries were present in 97 (93%) of patients. Of the patients with normal type of celiac trunk, 3 (2.9%) had a 4th branch of celiac trunk. 33 (31.8%) cases were reported as the first branch of left gastric artery from celiac trunk. In addition, gastrosplenic trunk 3 (2.9%), hepatosplenic trunk 3 (2.9%) and coeliomesenteric trunk 1 (0.96%) cases were detected. The results of our study were consistent with the literature. A detailed knowledge of the abdominal angioarchitecture that whether normal or variant, is thus considered a prerequisite for successful, uncomplicated abdominal surgeries and interventional radiological procedures. Therefore, should be always considered the anatomy and variations of celiac trunk and branches in clinical studies, angiographic procedures and surgical interventions.

Atherothrombosis is a complex disease in which cholesterol deposition, inflammation, and thrombus formation play a major role. Rupture of high-risk, vulnerable plaques is responsible for coronary thrombosis, the main cause of unstable angina, acute myocardial infarction, and sudden cardiac death. In addition to rupture, plaque erosion may also lead to occlusive thrombosis and acute coronary events. Atherothrombosis can be evaluated according to histologic criteria, most commonly categorized by the American Heart Association (AHA) classification. However, this classification does not include the thin cap fibroatheroma, the most common form of high-risk, vulnerable plaque. Furthermore, the AHA classification does not include plaque erosion. As a result, new classifications have emerged and are reviewed in this article. The disease is asymptomatic during a long period and dramatically changes its course when complicated by thrombosis. This is summarized in five phases, from early lesions to plaque rupture, followed by plaque healing and fibrocalcification. For the early phases, the role of endothelial dysfunction, cholesterol transport, high-density lipoprotein, and proteoglycans are discussed. Furthermore, the innate and adaptive immune response to autoantigens, the Toll-like receptors, and the mechanisms of calcification are carefully analyzed. For the advanced phases, the role of eccentric remodeling, vasa vasorum neovascularization, and mechanisms of plaque rupture are systematically evaluated. In the final thrombosis section, focal and circulating tissue factor associated with apoptotic macrophages and circulatory monocytes is examined, closing the link between inflammation, plaque rupture, and blood thrombogenicity.

Subjects aged over 65 years without symptomatic chest pain were recruited for the KLoSHA in 2006 by random stratified sampling (439 men and 561 women). Anthropometrics, biochemical parameters, body composition, and abdominal fat by computed tomography (CT) were ...

The number of studies focusing on the role of gender and language learning experience in interlanguage pragmatic development is limited in ESL contexts. Iranian EFL context is not an exception and few investigations have been conducted in this regard. Therefore, the current investigation attempted to study the impact of gender and English language learning experience (LLE) on speech-act interlanguage pragmatic (ILP) performance of Iranian EFL learners. Gender was treated as a biological factor and language learning experience was operationalized as the number of years spent learning English and the participants were divided into three groups of 1 to 2 years, 3 to five years, and plus 6 years. A multiple-choice discourse completion test (MDCT) including five common English speech acts (request, apology, refusal, complaint, and compliment/compliment responses) was developed and validated by the use of native speakers. A 35-item MDCT was achieved after two pilot studies by native and n...

The purpose of our study was to investigate the effect of iterative reconstruction (IR) as a dose reduction system on the image quality (IQ) of the adult head computed tomography (CT) at various low-dose levels, and to identify ways of setting the amount of dose reduction. We performed two noncontrast low-dose (LD) adult head CT protocols modified by lowering the tube current with IR which were decided in the light of a group of phantom studies. Two groups of patients, each 100 underwent noncontrast head CT with LD-I and LD-II, respectively. These groups were compared with 100 consecutive standard dose (STD) adult head CT protocol in terms of quantitative and qualitative IQ. The signal-to-noise ratio (SNR) of the white matter (WM) and gray matter (GM) and contrast-to-noise ratio (CNR) values in the LD groups were higher than the STD group. The differences were statistically significant. When the STD and the LD groups were compared qualitatively, no significant differences were found...

The objective of this study was to prospectively investigate the influence of oral, IV, and oral and IV contrast media on the information provided by MDCT at standard and simulated low radiation doses in adults suspected of having acute appendicitis. One hundred thirty-one consecutive patients (80 women, 51 men; age range, 18-87 years; mean age, 37 years) suspected of having appendicitis were randomly assigned to either ingest or not ingest iodinated contrast material. Thereafter, all patients underwent IV unenhanced and enhanced abdominopelvic MDCT with a 4 x 2.5 mm collimation at 120 kVp and 100 mAs(eff). Dose reduction corresponding to 30 mAs(eff) was simulated. Two radiologists independently read scans during separate sessions, assessed appendix visualization, and proposed a diagnosis (i.e., appendicitis or an alternative diagnosis). The final diagnosis was based on either surgical findings or clinical follow-up. Data were analyzed by factorial analysis of multiple correspondences followed by an ascending hierarchic classification method. Factorial analysis and ascending hierarchic classification revealed that, in terms of diagnostic correctness, reader influence predominated over the influence of IV and oral contrast media use and radiation dose but that correctness was also influenced by the patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s sex (p = 0.048) and was lower in cases of alternative diseases (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Visualization of the appendix depended predominantly on the reader rather than on the use of IV, oral, or oral and IV contrast agents or on radiation dose. Diagnostic correctness is much more influenced by the reader than by the use of contrast medium (oral, IV, or both) or of simulated low-radiation-dose technique.

The purpose of this study was to assess the diagnostic accuracy of MDCT for determining the prognostic factors, including the T category, lymph node metastasis, tumor size, and perineural invasion, in surgically proven intraductal papillary mucinous neoplasms (IPMNs) with an associated invasive carcinoma (IPMC) and to investigate the imaging findings. Our study group consisted of 38 patients with surgically proven IPMC who underwent preoperative dynamic CT. Two radiologists retrospectively assessed the morphologic type of IPMN, size of the cyst, size of the main pancreatic duct, and presence or absence of mural nodules. The radiologists also assessed the T category, lymph node metastasis, and perineural invasion. They graded the perineural invasion using a 3-point scale as follows: 1, normal; 2, streaky and strandlike structure in fat tissue as well as a fine, reticular pattern; and 3, irregular masses adjacent to the lesions. Statistical analyses were performed using receiver operating characteristic analysis, the McNemar test, and Fisher exact test. Kappa statistics were used to determine interobserver agreement. The morphologic types of IPMC included the main-duct type (n=11, 29%), combined type (n=18, 47%), and branch-duct type (n=9, 24%). The diagnostic accuracy for the T category was 73.7% (n=28) and 68.4% (n=26) and for the lymph node metastasis was 68.4% (n=26) and 76.3% (n=29), respectively, for the two readers, with moderate interobserver agreement (κ=0.636 and 0.708). The areas under the receiver operating characteristic curve for perineural invasion were 0.868 and 0.821. The sensitivity, specificity, and positive predictive value were 100%, 71.4%, 55.5%, and 90%, 71.4%, 52.9%, respectively. Interobserver agreement was moderate (κ=0.659). The tumor size seen on CT was not statistically different from the tumor size determined on pathology (3.9±[SD] 2.7 cm vs 3.8±2.1 cm, p=0.582). The main duct size was 11.5+6.2 mm. Mural nodules were detected in 74% (n=28) of our study patients. CT might be useful for preoperatively evaluating the T category, lymph node metastasis, tumor size, and perineural invasion of IPMC. Main pancreatic duct dilatation and the presence of mural nodules are common findings of IPMC.

The aim of this study was to use coronary computed tomographic (CT) angiography to characterize coronary artery involvement in patients with known Takayasu arteritis who present with anginal chest pain or shortness of breath. Takayasu arteritis is a primary vasculitis of the large vessels, which mainly affects the aorta and its branches but can also involve the coronary arteries. Coronary CT angiography allows visualization of the coronary vessels and can be used to detect both stenotic and nonstenotic coronary artery lesions. Eighteen consecutive patients with Takayasu arteritis and angina (typical or atypical) and/or dyspnea underwent contrast-enhanced 64-slice coronary CT angiography. The arterial injury was classified according to the Numano classification. Three patients had prior known coronary artery disease. Coronary arteries were evaluated concerning the presence of obstructive and nonobstructive lesions, and differences between the clinical presentations of patients with a...

ObjectiveMDCT is performed as first imaging examination for patients with acute abdomen in most Emergency Departments. Clinical suspicion of ischemic colitis and infarction is related to specific findings, however, differential diagnosis as well as the staging for a confirmed ischemic affection may be critical. The individual signs from ischemia to infarction of large bowel is a captivating topic. In this

Preliminary studies have shown the potential of myocardial computed tomography perfusion (CTP) analysis for ischemia detection in both animals and humans. To provide validation data on stress-rest CTP protocols as additive tools to improve the accuracy of multidetector computed tomography (MDCT) for coronary artery disease (CAD) in symptomatic patients. Ninety symptomatic patients with suspected CAD (62 ± 8 years, 66% males) underwent both MDCT and invasive coronary angiography (XA). The MDCT protocol included a prospective calcium score acquisition, a helical acquisition with retrospective gating during infusion of adenosine (140 μg/kg/min) and a prospective scan for computed tomography angiography (CTA) at rest (total effective radiation dose: 5.1 ± 0.8 mSv). Significant and higher-grade CADs were defined by the presence of ≥50% or ≥70% stenosis in at least one coronary artery, as evaluated by quantitative coronary angiography (QCA) using XA images. On a patient-based model, CTA sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) to detect ≥50% or ≥70% stenosis were 98%, 71%, 80%, and 97% (global accuracy 86%) and 100%, 60%, 64%, and 100% (accuracy 77%), respectively. An integrative approach of CTA and CTP results had the best performance for detection of CAD with sensitivity of 83%, specificity of 98%, PPV of 98%, and NPV of 84% (accuracy 84%) for detection of 50% stenosis and 97%, 90%, 88%, and 98% (accuracy 93%), respectively, for the 70% threshold. The integration of results had the best overall performance in all scenarios but was particularly advantageous in the prediction of higher-grade CAD, with an area under the curve of 0.93, compared with 0.80 for isolated CTA and 0.82 for CTP and in patients with severe calcifications (sensitivity 92%, specificity 87%, overall accuracy of 90%). The integration of functional and morphological data using CTA and CTP improved MDCT accuracy for detection of clinically relevant CAD at both thresholds of 50% and 70% in this intermediate to high pretest probability population.

The purpose of this study was to test the hypothesis, with noninvasive multimodality imaging, that allogeneic mesenchymal stem cells (MSCs) produce and/or stimulate active cardiac regeneration in vivo after myocardial infarction (MI). Although intramyocardial injection of allogeneic MSCs improves global cardiac function after MI, the mechanism(s) underlying this phenomenon are incompletely understood. We employed magnetic resonance imaging (MRI) and multi-detector computed tomography (MDCT) imaging in MSC-treated pigs (n = 10) and control subjects (n = 12) serially for a 2-month period after anterior MI. A sub-endocardial rim of tissue, demonstrated with MDCT, was assessed for regional contraction with MRI tagging. Rim thickness was also measured on gross pathological specimens, to confirm the findings of the MDCT imaging, and the size of cardiomyocytes was measured in the sub-endocardial rim and the non-infarct zone. Multi-detector computed tomography demonstrated increasing thickness of sub-endocardial viable myocardium in the infarct zone in MSC-treated animals (1.0 +/- 0.2 mm to 2.0 +/- 0.3 mm, 1 and 8 weeks after MI, respectively, p = 0.028, n = 4) and a corresponding reduction in infarct scar (5.1 +/- 0.5 mm to 3.6 +/- 0.2 mm, p = 0.044). No changes occurred in control subjects (n = 4). Tagging MRI demonstrated time-dependent recovery of active contractility paralleling new tissue appearance. This rim was composed of morphologically normal cardiomyocytes, which were smaller in MSC-treated versus control subjects (11.6 +/- 0.2 mum vs. 12.6 +/- 0.2 mum, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). With serially obtained MRI and MDCT, we demonstrate in vivo reappearance of myocardial tissue in the MI zone accompanied by time-dependent restoration of contractile function. These data are consistent with a regenerative process, highlight the value of noninvasive multimodality imaging to assess the structural and functional basis for myocardial regenerative strategies, and have potential clinical applications.