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The purpose of this study was to estimate the gamma-aminobutyric acid (GABA) and glutamate plus glutamine (Glx) concentrations in the cortical tubers of patients with tuberous sclerosis complex (TSC) using the MEGA-editing J-difference method and a stimulated echo-acquisition mode with a short echo time, and to determine which abnormality was more dominant between GABA and Glx in patients with TSC with epilepsy. This study included six patients with TSC (mean age, 4.3 years) and seven control subjects (mean age, 4.8 years). Measurements were obtained with a three-Tesla apparatus and postprocessing was conducted with an LCModel. The GABA level in the cortical gray matter (cgGABA) was calculated as a result of segmentation in voxels and from the literature values for gray and white matter ratios for GABA. Increased GABA and myo-inositol (mI) concentrations and a decreased N-acetyl aspartate (NAA) concentration were observed in the cortical tubers. The cgGABA level, and cgGABA/NAA and cgGABA/Glx ratios were also higher in patients with TSC than in control subjects. No significant difference was found in Glx concentration between patients with TSC and control subjects. Although the number of patients with TSC in this study was small, the increase in GABA and no significant change in Glx were consistent with previous neurochemical studies and support the hypothesis that brain GABA plays a key role in the pathophysiology of epilepsy during the process of neuronal development.

We report 2 patients of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and consider the pathophysiology of stroke-like lesions, using magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI) on MRI, perfusion imaging on MRI, and 1H magnetic resonance spectroscopy (1H-MRS). In Patient 1, T2-weighted imaging (T2-WI) on MRI at onset and even at 44 days after onset of the stroke-like episode showed high intensity in left parietal, temporal, and occipital lobe lesions. In the temporal lobe lesion, the apparent diffusion coefficient (ADC) at 44 days after onset was higher (average: 1.219x10(-3)mm2/s) than that in a normal region (average: 0.796x10(-3)mm2/s). (1)H-MRS of the left parietal lobe lesion at the same day showed a decrease in N-acetylaspartate/(creatine+phosphocreatine) (NAA/Cr) (0.43) and a peak in lactate. 1H-MRS of the contralateral side at the same day showed NAA/Cr (1.57) and no peak in lactate. Thereafter, ADC gradually decreased and NAA/Cr gradually increased, and the peak in lactate disappeared in the lesion. In Patient 2, T2-WI at onset showed high intensity in bilateral occipital lobe lesions. In the left occipital lobe lesion, ADC at the same day was higher (1.082x10(-3)mm2/s) than that in a normal region (average: 0.841x10(-3)mm2/s). (1)H-MRS of the left occipital lobe lesion at the same day showed a decrease of NAA (3.0mM) and a peak in lactate (13.1mM) (measured by LCModel). In 1H-MRS of the normal left parietooccipital lobe at 4 months before onset, NAA was 7.6mM and there was no peak in lactate (0mM). Perfusion imaging at onset showed high intensity in bilateral occipital lobes, which indicated hyperperfusion in stroke-like lesions. Thereafter, ADC gradually decreased and the peak in lactate partially decreased, and the low concentration of NAA persisted (regardless of the partial recovery) in the lesion. These results suggest that the stroke-like episodes is related to vasogenic edema, hyperperfusion, and neuronal damage. Acute oxidative phosphorylation defect may have a crucial role in the pathophysiology of stroke-like episodes.

Objective: There has been reports on the usefulness of diffusion tensor imaging (DTI) about age-or disease-related degradation. DTI is generally evaluated by the region of interest (ROI) methodology. In this study, we applied a statistical way using Statistical Parametric Mapping (SPM) to assess normal aging by DTI and compared results of these two methods.Methods: Ten young and ten senior normal volunteers were examined. On SPM, tensor images were changed into normalized tensor images. They were compared between the two groups by t-test.Results: In the senior group, fractional anisotropy (FA) values were higher on the basal ganglia, cingulated gyrus and other cortical gray matter, lower in the corona radiata, internal capsule, centrum semiovale and corpus callosum by using SPM. In the ROI method, the results were almost compatible except in the brain periphery.Conclusions: Aging changes on water diffusion anisotropy was clearly shown by SPM method which would be useful to evaluate change of water diffusion anisotropy without operator bias even in clinical setting instead of ROI measurement. J. Med. Invest. 52: 186-190, August, 2005

The aim of this study was to compare diffusion-weighted imaging (DWI) at 3.0 T and 1.5 T by evaluating the apparent diffusion coefficient (ADC) value and visibility of breast cancer in the same patients.A total of 13 patients (16 lesions) with breast cancer underwent DWI at 3.0 T and 1.5 T. Tumors were classified into two groups based on the lesion size. The ADC values were measured, and visibility of the tumors was scored blindly.No significant difference was found for ADC values between 3.0 T and 1.5 T in either group (P0.05). All of the large lesions were visible clearly at both magnetic field strengths, and image scores were not different (P0.05). In contrast, small lesions were more clearly visible and had better image scores at 3.0 T than at 1.5 T (P0.001).Small cancers were more clearly visible on DWI at 3.0 T than 1.5 T.

Objective: Simple and reliable identification methods for sentinel lymph nodes (SLNs) which do not use radioisotope are essential for early breast cancer patients in community hospitals in Japan. The purpose of this paper is to demonstrate the feasibility and efficacy of computed tomography (CT) lymphography for SLN detection. Methods: The study included 15 cases with Tl or T2 breast cancer. After subcutaneous injection of 1 mL of iopamidol in 1 subareolar area of the affected breast, CT scanning was carried out and 3-dimensional (3D) CT images were created. SLNs predicted from images and CT values were assessed as to whether they were identical to those identified by the dye method. Results: An enhanced lymph vessel draining into SLN was demonstrated in 11 cases (73%) and an enhanced SLN in 10 cases (67%). 3D images clearly revealed the anatomic relationship between lymph vessels, SLN, and the surrounding structures. In addition, SLN could be predicted by the change of CT value in the time-course in another case. In total, SLN in 13 cases (87%) could be predicted. All SLNs suggested from CT lymphography were identified by the dye method. No significant adverse effect was noted in any case. Conclusions: The present clinical trial indicated that subcutaneous injection of nonionic contrast medium with CT scanning seems to be a promising method for the demonstration of a draining lymph vessel and SLN. The CT value time-course may also provide some important information. Further trials will be needed for the successful establishment of this CT lymphography-guided method for SLN identification.

This study examined whether 3D CT imaging with lymphoscintigraphy (LSG) is useful when performing sentinel node biopsy (SNB) in a community hospital where radioisotope with gamma-probe (RI method) is unavailable.From June to November 2002, 35 T1/T2 clinically node-negative breast cancer patients underwent LSG in a university nuclear medicine department. Skin areas above LSG hot spots were marked, helical CT scanning was performed and axillary 3D images were created in our hospital. The SLN predicted from the 3D images were examined for agreement with the dye method.SLNs were detected with dye in 32 out of 35 patients (91.4%). In 31 of those 32 (96.9%), the SLN predicted from 3D CT images was the same. Even in the 3 dye-negative patients, CT imaging predicted the SLN. SNB including sampling was successful in 34 patients (97.1%).3D CT imaging with LSG enables SNB even if the RI method is impossible.