Yoshiharu Nakayama

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PURPOSE To prospectively investigate the effect of low tube voltage on radiation dose, contrast enhancement, image quality, and image noise at abdominal dynamic computed tomography (CT). MATERIALS AND METHODS The institutional review board approved this study. Prior informed consent was obtained from all patients. Forty patients (24 women, 16 men; mean(More)
PURPOSE To evaluate the effect of a computer-aided diagnosis (CAD) system on the diagnostic performance of radiologists for the estimation of the malignancy of pulmonary nodules on thin-section helical computed tomographic (CT) scans. MATERIALS AND METHODS The institutional review board approved use of the CT database; informed specific study-related(More)
PURPOSE To prospectively compare in vivo hepatic automated volumetry with manual volumetry and measured liver volume. MATERIALS AND METHODS The study was conducted in accordance with the guidelines of the Institutional Review Board of Kumamoto University (Japan). Patient informed consent was obtained. Preoperative multisection computed tomography (CT) was(More)
PURPOSE To compare enhancement of the aorta, portal vein, liver, and tumor with contrast medium of a higher iodine concentration to that with one of a standard iodine concentration for liver dynamic CT within the same patient with known liver cirrhosis and hepatocellular carcinoma (HCC). MATERIALS AND METHODS Fifty-three patients with known cirrhosis and(More)
OBJECTIVE The purpose of our study was to compare aortic CT angiography performed at a low tube voltage and reduced dose of contrast material with standard-voltage, standard-contrast-dose CT angiography. SUBJECTS AND METHODS We evaluated 74 patients for aortic disease on MDCT angiography (collimation, 16 x 1.5 mm; beam pitch, 0.9). In 36 patients, we used(More)
The aim of this study was to investigate how accurately we could diagnose the level of gastrointestinal (GI) tract perforation using multidetector computed tomography (MDCT). We reviewed 155 patients with surgically confirmed GI tract perforation. MDCT scans were obtained with eight-detector CT; 5 mm thick axial images and 2.5 mm thick coronal multiplanar(More)
The purpose of our study was to investigate whether quantitative diffusion-weighted images (DWI) were useful for monitoring the therapeutic response of primary bone tumors. We encountered 18 osteogenic and Ewing sarcomas. Magnetic resonance (MR) images were performed in all patients before and after therapy. We measured the apparent diffusion coefficient(More)
PURPOSE To reduce radiation dose from abdominal computed tomography (CT) without degradation of low-contrast detectability by using a technique with low tube voltage (90 kV). MATERIALS AND METHODS The institutional review board approved the participation of the radiologists in the observer performance test, and informed consent was obtained from all(More)
OBJECTIVE To determine the usefulness of prostate-specific antigen (PSA) screening for prostate cancer in patients with end-stage renal disease (ESRD), as although serum PSA is effective in the early detection of this cancer in the general population, there are few reports of its utility in patients with ESRD. PATIENTS AND METHODS Blood samples were(More)
PURPOSE To assess the value of multidetector CT portography in visualizing varices and portosystemic collaterals in comparison with conventional portography, and to compare the visualizations obtained by three rendering models (volume rendering, VR; minimum intensity projection, MIP; and shaded surface display, SSD). METHODS A total of 46 patients with(More)