Repetitive transcranial magnetic stimulation (rTMS) recently has been assessed as a noninvasive t... more Repetitive transcranial magnetic stimulation (rTMS) recently has been assessed as a noninvasive treatment modality for movement and psychiatric disorders, whereas the mechanism underlying the therapeutic effects is not fully understood. Studies in rodents showed lasting functional changes in some selected regions, such as limbic-associated structures, but unfocused brain stimulation did not clarify the regional effects. To address the topographical and temporal profiles of the effects on glucose metabolism in primate brain, we performed rTMS and repeated (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) before, during, and up to 16 days after rTMS in anesthetized cynomologous monkeys. We delivered a total of 2,000 pulses of 5 Hz-rTMS over the right precentral gyrus using a small-sized eight-figured coil that induced a localized electrical field. Voxel-based analysis in a standard space of the macaque brain showed statistically robust changes in FDG uptake: a decrease in the motor/premotor cortices and an increase in the limbic-associated areas involving the anterior/posterior cingulate, and orbitofrontal cortices. Interestingly, these uptake changes continued for at least 8 days and the magnitude of the lasting effects in the limbic-related areas was negatively correlated across subjects with those in the motor/premotor cortices. The results demonstrate that motor rTMS has a long-term lasting effect on motor-related regions and distant limbic-related areas via functional connections.
We examined the temperature of the intraventricular cerebrospinal fluid (Tv) in patients with Par... more We examined the temperature of the intraventricular cerebrospinal fluid (Tv) in patients with Parkinson's disease (PD) and those with multiple system atrophy (MSA) in comparison with healthy subjects, and we examined normal changes in this temperature with aging. Tv was estimated by magnetic resonance (MR) diffusion-weighted imaging (DWI) thermometry in 36 PD patients (19 males, 17 females), 34 MSA patients (17 males, 17 females), 64 age-matched controls (27 men, 37 women), and 114 all-age adult controls (47 men, 67 women; 28-89 years old). The volume of lateral ventricles was also estimated using FreeSurfer in all subjects. Tv and ventricular volume data were compared among the PD and MSA patients and age-matched controls. We also evaluated the relationship between Tv and age in the 114 all-age controls, controlling for ventricular volume. Men and women were analyzed separately. The male PD and MSA patients had significantly higher Tv values compared to the male controls, with ...
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2004
In Alzheimer's disease (AD), regional cerebral blood flow (rCBF) in the posterior cingulate g... more In Alzheimer's disease (AD), regional cerebral blood flow (rCBF) in the posterior cingulate gyri and precunei has been reported to decrease even at a very early stage. It may be helpful to use statistical image analysis to distinguish slight decreases in rCBF in this area. We compared a 3-dimensional stereotactic surface projection (3D-SSP) technique with visual inspection in the discrimination of patients with very early AD from age-matched controls using brain perfusion SPECT. SPECT was obtained in 38 patients with probable AD at a very early stage and after a mean interval of 15 mo and in 76 age-matched healthy volunteers. We randomly divided these subjects into 2 groups. The first group was used to identify the areas with significant decreases of rCBF in patients compared with healthy control subjects based on the voxel-based analysis using 3D-SSP. The second group was used to compare the discrimination ability between patients and control subjects by 3D-SSP with that by vis...
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2002
Morphologic and functional imaging studies have not always given concordant results about brain a... more Morphologic and functional imaging studies have not always given concordant results about brain areas showing atrophic changes and reduced flow or metabolism in Alzheimer's disease (AD). The aim of this study was to determine the initial abnormality and the longitudinal changes in both morphologic and functional measurements for the same individuals with AD. We investigated 15 patients with mild AD and 25 age-matched healthy volunteers. The AD patients underwent both MRI and SPECT 3 times at intervals of approximately 1 y. The gray matter volume, as segmented from MRI, and the regional cerebral blood flow (rCBF), as measured by SPECT, of AD patients were compared with those of healthy volunteers using statistical parametric mapping, which is a voxel-based analysis in stereotactic space. Considerable discordance between areas of regional atrophy and areas of decreased rCBF was observed. The medial temporal areas showed a faster and more extensive reduction of gray matter volume t...
The voxel-based morphometry (VBM) technique using brain magnetic resonance imaging (MRI) objectiv... more The voxel-based morphometry (VBM) technique using brain magnetic resonance imaging (MRI) objectively maps gray matter loss on a voxel-by-voxel basis after anatomic standardization. In patients with Alzheimer's disease (AD), reductions of gray matter volume, mainly in the medial temporal structures, have been reported; however, inhomogeneity and geometric distortion of the field intensity hampers the reproducibility of MRI. In the present study, we developed a novel computed tomography (CT)-based VBM method and used this technique to detect volume loss in AD patients as compared with normal controls. The results were compared with MRI-based VBM using the same subjects. Pittsburgh Compound B ((11)C-PIB) positron emission tomography (PET)/CT was performed and two experts in neuro-nuclear medicine judged whether regional amyloid β load was consistent with a diagnosis of AD. Before the injection of (11)C-PIB, high-quality CT scans were obtained using the same PET/CT equipment. MRI wa...
To assess the usefulness of positron emission tomography combined with computed tomography using ... more To assess the usefulness of positron emission tomography combined with computed tomography using (18)F-fluorodeoxyglucose (FDG PET/CT) for optimizing chemotherapy during neoadjuvant chemotherapy for primary breast cancer. One hundred and eight patients (110 tumors) with breast cancer (≥2 cm, stages II and III) received neoadjuvant chemotherapy consisting of an anthracycline-based regimen and taxane. The maximal value of the baseline standardized uptake value (SUV) and the change in SUV after four cycles of an anthracycline-based regimen relative to baseline SUV were assessed for predicting pathological complete response (pCR) after sequential taxane. Tumors with pCR had significantly higher baseline SUV (9.3 ± 3.7 SD) compared to those with non-pCR (7.2 ± 3.8 SD) (p = 0.02), but there was a considerable overlap between two groups. On PET scan after four cycles of chemotherapy, thirty-three patients (33.7%) with a 72.1% or greater reduction in SUV were considered as responders and th...
Skeletal muscle blood flow (SMBF) is a crucial indicator of impaired peripheral circulation. Alth... more Skeletal muscle blood flow (SMBF) is a crucial indicator of impaired peripheral circulation. Although 133Xe has long been used for estimation of regional SMBF, its lipophilic and volatile nature hampers precise measurement. Therefore, we established an improved method based on 99mTc-pertechnetate ion (99mTcO-4) clearance. Ten healthy male volunteers including five rugby players and five non-athletes (each group aged 25-35 years) received injection of 99mTcO-4 into the bilateral tibialis anterior muscles and gastrocnemius muscles (GCMs). The radioactivity of 99mTcO-4 before, during, and after toe-up or treadmill exercise was traced using a gamma-camera. Regional SMBF in absolute values (in ml/min/100 g muscle) was then calculated based on the half-time obtained from the time-activity curve. In both the groups, SMBF in tibialis anterior muscle changed similarly with values at the same levels. In contrast, SMBF in GCM showed marked difference between the two groups: in rugby players, SMBF in GCM returned to the baseline level (6.5+/-1.7, n=10) immediately after treadmill exercise, whereas that in non-athletes remained high (16.2+/-3.2, n=10). Regional SMBF measured by 99mTcO-4 clearance can indicate effectiveness of exercise training, and would be a diagnostic tool and prognostic indicator for use in patients with impaired peripheral circulation.
Previous reports have yielded controversial results concerning gender differences in regional cer... more Previous reports have yielded controversial results concerning gender differences in regional cerebral blood flow (rCBF). To elucidate this issue, we compared 99mTc ethyl cysteinate dimer single photon emission computed tomography (SPECT) images for brain perfusion between aged-matched healthy men and women after correction for partial volume effects (PVEs). Brain perfusion SPECT in the resting state was performed on 40 healthy, right-handed subjects, 20 men and 20 women, with an age range of 58-86 years, who did not differ sociodemographically. PVE correction was performed using grey matter volume measured by magnetic resonance imaging. Statistical parametric mapping was used for the analysis of the adjusted rCBF images of relative flow distribution. The PVE correction revealed that women had higher rCBF in left inferior frontal gyrus, bilateral middle temporal gyri, and left superior temporal gyrus. Men had higher rCBF in left superior frontal gyrus, right medial frontal gyrus, right superior parietal lobule, right postcentral gyrus, right cerebellum, right middle frontal gyrus, right fusiform gyrus, and right precuneus. Significant gender differences in rCBF existed in these healthy volunteers. The PVE correction of SPECT images revealed gender differences that were consistent with the universal findings of better performance on verbal tasks in women and on visuospatial tasks in men.
Respiratory monitoring systems are used to detect the respiratory phase of patients during the pl... more Respiratory monitoring systems are used to detect the respiratory phase of patients during the planning and administration of respiratory gated radiotherapy by using four-dimensional computed tomography (4DCT) or 4D positron-emission tomography/CT (4DPET/CT) and the linear accelerator (linac), respectively. Generally, identical respiratory monitoring systems are used for 4DCT, 4DPET/CT, and linac. However, different systems are sometimes used in combination because the accessibility of the respiratory monitoring systems may differ by manufacturer. The combined use of different respiratory monitoring systems in phase-based gating is of concern because the differences in the timing of tags (end-respiration signals algorithmically determined by the respiratory monitoring system), defined by the two systems, may result in phase differences, The purpose of this study is to estimate this difference and evaluate its effect on 4DCT data. Ten patients (seven men and three women) with a median age of 75 yr (range: 57-84 yr) were treated by gated stereotactic body radiation therapy between April and December 2009. Two types of respiratory monitoring systems--RPM (Varian Medical Systems) and AZ-733V (Anzai MEDICAL)--were placed on the abdominal surface of the patients, and the respiratory signals were acquired by both systems. The relationship between the amplitude peak and the tag obtained by each respiratory system was analyzed for each patient. Further, the 4DCT images were reconstructed by using the signals obtained from both the RPM and the AZ-733V systems, and the tumor volumes and the tumor centroid positions in the craniocaudal plane were analyzed for each patient. The correlation factor between the respiratory signals from the RPM system and AZ-733V system was 0.990 (range: 0.940-0.994). The amplitude peak of the RPM system corresponded well with that of the AZ-733V system. The median +/- standard deviation of the phase difference for all the patients ranged from -4.3 +/- 7.1% to 3.5 +/- 2.2%. In the case of some patients, differences were noted between the two systems in the estimation of the tumor centroid position and tumor shape. The estimation of the position of the tumor centroid and tumor shape may vary with the use of different respiratory monitoring systems. This implies that it is preferable to use the same respiratory monitoring system with 4DCT, 4DPET-CT, and linac.
Repetitive transcranial magnetic stimulation (rTMS) recently has been assessed as a noninvasive t... more Repetitive transcranial magnetic stimulation (rTMS) recently has been assessed as a noninvasive treatment modality for movement and psychiatric disorders, whereas the mechanism underlying the therapeutic effects is not fully understood. Studies in rodents showed lasting functional changes in some selected regions, such as limbic-associated structures, but unfocused brain stimulation did not clarify the regional effects. To address the topographical and temporal profiles of the effects on glucose metabolism in primate brain, we performed rTMS and repeated (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) before, during, and up to 16 days after rTMS in anesthetized cynomologous monkeys. We delivered a total of 2,000 pulses of 5 Hz-rTMS over the right precentral gyrus using a small-sized eight-figured coil that induced a localized electrical field. Voxel-based analysis in a standard space of the macaque brain showed statistically robust changes in FDG uptake: a decrease in the motor/premotor cortices and an increase in the limbic-associated areas involving the anterior/posterior cingulate, and orbitofrontal cortices. Interestingly, these uptake changes continued for at least 8 days and the magnitude of the lasting effects in the limbic-related areas was negatively correlated across subjects with those in the motor/premotor cortices. The results demonstrate that motor rTMS has a long-term lasting effect on motor-related regions and distant limbic-related areas via functional connections.
We examined the temperature of the intraventricular cerebrospinal fluid (Tv) in patients with Par... more We examined the temperature of the intraventricular cerebrospinal fluid (Tv) in patients with Parkinson's disease (PD) and those with multiple system atrophy (MSA) in comparison with healthy subjects, and we examined normal changes in this temperature with aging. Tv was estimated by magnetic resonance (MR) diffusion-weighted imaging (DWI) thermometry in 36 PD patients (19 males, 17 females), 34 MSA patients (17 males, 17 females), 64 age-matched controls (27 men, 37 women), and 114 all-age adult controls (47 men, 67 women; 28-89 years old). The volume of lateral ventricles was also estimated using FreeSurfer in all subjects. Tv and ventricular volume data were compared among the PD and MSA patients and age-matched controls. We also evaluated the relationship between Tv and age in the 114 all-age controls, controlling for ventricular volume. Men and women were analyzed separately. The male PD and MSA patients had significantly higher Tv values compared to the male controls, with ...
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2004
In Alzheimer's disease (AD), regional cerebral blood flow (rCBF) in the posterior cingulate g... more In Alzheimer's disease (AD), regional cerebral blood flow (rCBF) in the posterior cingulate gyri and precunei has been reported to decrease even at a very early stage. It may be helpful to use statistical image analysis to distinguish slight decreases in rCBF in this area. We compared a 3-dimensional stereotactic surface projection (3D-SSP) technique with visual inspection in the discrimination of patients with very early AD from age-matched controls using brain perfusion SPECT. SPECT was obtained in 38 patients with probable AD at a very early stage and after a mean interval of 15 mo and in 76 age-matched healthy volunteers. We randomly divided these subjects into 2 groups. The first group was used to identify the areas with significant decreases of rCBF in patients compared with healthy control subjects based on the voxel-based analysis using 3D-SSP. The second group was used to compare the discrimination ability between patients and control subjects by 3D-SSP with that by vis...
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2002
Morphologic and functional imaging studies have not always given concordant results about brain a... more Morphologic and functional imaging studies have not always given concordant results about brain areas showing atrophic changes and reduced flow or metabolism in Alzheimer's disease (AD). The aim of this study was to determine the initial abnormality and the longitudinal changes in both morphologic and functional measurements for the same individuals with AD. We investigated 15 patients with mild AD and 25 age-matched healthy volunteers. The AD patients underwent both MRI and SPECT 3 times at intervals of approximately 1 y. The gray matter volume, as segmented from MRI, and the regional cerebral blood flow (rCBF), as measured by SPECT, of AD patients were compared with those of healthy volunteers using statistical parametric mapping, which is a voxel-based analysis in stereotactic space. Considerable discordance between areas of regional atrophy and areas of decreased rCBF was observed. The medial temporal areas showed a faster and more extensive reduction of gray matter volume t...
The voxel-based morphometry (VBM) technique using brain magnetic resonance imaging (MRI) objectiv... more The voxel-based morphometry (VBM) technique using brain magnetic resonance imaging (MRI) objectively maps gray matter loss on a voxel-by-voxel basis after anatomic standardization. In patients with Alzheimer's disease (AD), reductions of gray matter volume, mainly in the medial temporal structures, have been reported; however, inhomogeneity and geometric distortion of the field intensity hampers the reproducibility of MRI. In the present study, we developed a novel computed tomography (CT)-based VBM method and used this technique to detect volume loss in AD patients as compared with normal controls. The results were compared with MRI-based VBM using the same subjects. Pittsburgh Compound B ((11)C-PIB) positron emission tomography (PET)/CT was performed and two experts in neuro-nuclear medicine judged whether regional amyloid β load was consistent with a diagnosis of AD. Before the injection of (11)C-PIB, high-quality CT scans were obtained using the same PET/CT equipment. MRI wa...
To assess the usefulness of positron emission tomography combined with computed tomography using ... more To assess the usefulness of positron emission tomography combined with computed tomography using (18)F-fluorodeoxyglucose (FDG PET/CT) for optimizing chemotherapy during neoadjuvant chemotherapy for primary breast cancer. One hundred and eight patients (110 tumors) with breast cancer (≥2 cm, stages II and III) received neoadjuvant chemotherapy consisting of an anthracycline-based regimen and taxane. The maximal value of the baseline standardized uptake value (SUV) and the change in SUV after four cycles of an anthracycline-based regimen relative to baseline SUV were assessed for predicting pathological complete response (pCR) after sequential taxane. Tumors with pCR had significantly higher baseline SUV (9.3 ± 3.7 SD) compared to those with non-pCR (7.2 ± 3.8 SD) (p = 0.02), but there was a considerable overlap between two groups. On PET scan after four cycles of chemotherapy, thirty-three patients (33.7%) with a 72.1% or greater reduction in SUV were considered as responders and th...
Skeletal muscle blood flow (SMBF) is a crucial indicator of impaired peripheral circulation. Alth... more Skeletal muscle blood flow (SMBF) is a crucial indicator of impaired peripheral circulation. Although 133Xe has long been used for estimation of regional SMBF, its lipophilic and volatile nature hampers precise measurement. Therefore, we established an improved method based on 99mTc-pertechnetate ion (99mTcO-4) clearance. Ten healthy male volunteers including five rugby players and five non-athletes (each group aged 25-35 years) received injection of 99mTcO-4 into the bilateral tibialis anterior muscles and gastrocnemius muscles (GCMs). The radioactivity of 99mTcO-4 before, during, and after toe-up or treadmill exercise was traced using a gamma-camera. Regional SMBF in absolute values (in ml/min/100 g muscle) was then calculated based on the half-time obtained from the time-activity curve. In both the groups, SMBF in tibialis anterior muscle changed similarly with values at the same levels. In contrast, SMBF in GCM showed marked difference between the two groups: in rugby players, SMBF in GCM returned to the baseline level (6.5+/-1.7, n=10) immediately after treadmill exercise, whereas that in non-athletes remained high (16.2+/-3.2, n=10). Regional SMBF measured by 99mTcO-4 clearance can indicate effectiveness of exercise training, and would be a diagnostic tool and prognostic indicator for use in patients with impaired peripheral circulation.
Previous reports have yielded controversial results concerning gender differences in regional cer... more Previous reports have yielded controversial results concerning gender differences in regional cerebral blood flow (rCBF). To elucidate this issue, we compared 99mTc ethyl cysteinate dimer single photon emission computed tomography (SPECT) images for brain perfusion between aged-matched healthy men and women after correction for partial volume effects (PVEs). Brain perfusion SPECT in the resting state was performed on 40 healthy, right-handed subjects, 20 men and 20 women, with an age range of 58-86 years, who did not differ sociodemographically. PVE correction was performed using grey matter volume measured by magnetic resonance imaging. Statistical parametric mapping was used for the analysis of the adjusted rCBF images of relative flow distribution. The PVE correction revealed that women had higher rCBF in left inferior frontal gyrus, bilateral middle temporal gyri, and left superior temporal gyrus. Men had higher rCBF in left superior frontal gyrus, right medial frontal gyrus, right superior parietal lobule, right postcentral gyrus, right cerebellum, right middle frontal gyrus, right fusiform gyrus, and right precuneus. Significant gender differences in rCBF existed in these healthy volunteers. The PVE correction of SPECT images revealed gender differences that were consistent with the universal findings of better performance on verbal tasks in women and on visuospatial tasks in men.
Respiratory monitoring systems are used to detect the respiratory phase of patients during the pl... more Respiratory monitoring systems are used to detect the respiratory phase of patients during the planning and administration of respiratory gated radiotherapy by using four-dimensional computed tomography (4DCT) or 4D positron-emission tomography/CT (4DPET/CT) and the linear accelerator (linac), respectively. Generally, identical respiratory monitoring systems are used for 4DCT, 4DPET/CT, and linac. However, different systems are sometimes used in combination because the accessibility of the respiratory monitoring systems may differ by manufacturer. The combined use of different respiratory monitoring systems in phase-based gating is of concern because the differences in the timing of tags (end-respiration signals algorithmically determined by the respiratory monitoring system), defined by the two systems, may result in phase differences, The purpose of this study is to estimate this difference and evaluate its effect on 4DCT data. Ten patients (seven men and three women) with a median age of 75 yr (range: 57-84 yr) were treated by gated stereotactic body radiation therapy between April and December 2009. Two types of respiratory monitoring systems--RPM (Varian Medical Systems) and AZ-733V (Anzai MEDICAL)--were placed on the abdominal surface of the patients, and the respiratory signals were acquired by both systems. The relationship between the amplitude peak and the tag obtained by each respiratory system was analyzed for each patient. Further, the 4DCT images were reconstructed by using the signals obtained from both the RPM and the AZ-733V systems, and the tumor volumes and the tumor centroid positions in the craniocaudal plane were analyzed for each patient. The correlation factor between the respiratory signals from the RPM system and AZ-733V system was 0.990 (range: 0.940-0.994). The amplitude peak of the RPM system corresponded well with that of the AZ-733V system. The median +/- standard deviation of the phase difference for all the patients ranged from -4.3 +/- 7.1% to 3.5 +/- 2.2%. In the case of some patients, differences were noted between the two systems in the estimation of the tumor centroid position and tumor shape. The estimation of the position of the tumor centroid and tumor shape may vary with the use of different respiratory monitoring systems. This implies that it is preferable to use the same respiratory monitoring system with 4DCT, 4DPET-CT, and linac.
Uploads
Papers