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BACKGROUND AND PURPOSE Responses of the auditory cortex to sound during sleep have been explored with somewhat discrepant results. The purpose of this study was to investigate the effect of stage 1 sleep on signal intensity changes in the auditory cortex in response to pure tone stimulus measured by functional MR imaging. METHODS Six sleep-deprived(More)
A noninvasive technique for assessing tumor tissue characteristics is required to assist preoperative surgical planning for malignant brain tumors. Preoperative information on tumor cell density within a tumor would help better define the target for tumor biopsy, resulting in more accurate diagnosis and grading of malignant brain tumors. One possible source(More)
To determine the amount of iron deposits in the basal ganglia, we examined 13 healthy volunteers with a 1.5 T MRI system using three transverse relaxation rates measured with two sequences. The transverse relaxation rates comprise the reversible contribution (R2') and irreversible contribution (R2) to a phase-reversal 180 degrees -pulse sequence. The(More)
BACKGROUND Depression is a common mental disorder. Several studies suggest that lifestyle and health status are associated with depression. However, only a few large-scale longitudinal studies have been conducted on this topic. METHODS The subjects were middle-aged and elderly Japanese adults between the ages of 40 and 69 years. A total of 9,650(More)
Measuring the thickness of sheet-like thin anatomical structures, such as articular cartilage and brain cortex, in three-dimensional (3-D) magnetic resonance (MR) images is an important diagnostic procedure. This paper investigates the fundamental limits on the accuracy of thickness determination in MR images. We defined thickness here as the distance(More)
In the context of quantitative functional MRI (fMRI), deoxyhemoglobin (dHb) content is the essential physiological parameter for calibrating the blood oxygenation level-dependent (BOLD) signal. In studies on humans, the baseline dHb content or its equivalent has been evaluated indirectly by means of carbon dioxide breathing as a physiological reference(More)
Lung cancer is the leading cause of cancer-related death worldwide. Epidermal growth factor receptor (EGFR) - tyrosine kinase inhibitor (TKI) is used for the patients with EGFR-mutant lung cancer. Recently, phase III studies in the patients with EGFR-mutant demonstrated that EGFR-TKI monotherapy improved progression-free survival compared with(More)
Multimodal imaging is one of the necessary steps in the treatment of malignant brain tumors, and use of magnetic resonance imaging (MRI) and positron emission tomography (PET) are the current gold standard technique for the morphological and biological assessment of malignant brain tumors. In addition, fractional anisotropy (FA) obtained from diffusion(More)