Yasunori Nagayama

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To retrospectively evaluate the image quality and radiation dose of 100-kVp scans with sinogram-affirmed iterative reconstruction (IR) for unenhanced head CT in adolescents. Sixty-nine patients aged 12–17 years underwent head CT under 120- (n = 34) or 100-kVp (n = 35) protocols. The 120-kVp images were reconstructed with filtered back-projection (FBP),(More)
A 63-year-old woman presented with systemic erythema and Raynaud's phenomenon in June, 1987. Past medical and family histories were unremarkable. Discoid lupus lesions in the left arm and polyarthritis in the left leg were noted. Ultrasonography revealed pericardial effusion. Laboratory data were positive for antinuclear antibody (speckled pattern),(More)
To evaluate the image quality and lesion conspicuity of virtual-monochromatic-imaging (VMI) with dual-layer DECT (DL-DECT) for reduced-iodine-load multiphasic-hepatic CT. Forty-five adults with renal dysfunction who had undergone hepatic DL-DECT with 300-mgI/kg were included. VMI (40–70-keV, DL-DECT-VMI) was generated at each enhancement phase. As controls,(More)
We describe a case of ischemia complicating acute small-bowel obstruction in which retrospective on-demand spectral analysis using dual-layer spectral detector computed tomography (CT) provided a higher degree of confidence pertaining to the diagnosis. Dual-layer spectral detector CT enables retrospective on-demand spectral analysis, including virtual(More)
BACKGROUND Cardiac computed tomography (CT) has the potential for fully four-dimensional (4D for 3D plus time) motion analysis of the heart. We aimed at developing a method for assessment and presentation of the 4D motion for multi-phase, contrast-enhanced cardiac CT data sets and demonstrating its clinical applicability. METHODS Four patients with normal(More)
PURPOSE To evaluate the effect of a composite radiofrequency (RF) pulse on saturation recovery (SR) myocardial T1 mapping using a 3T magnetic resonance (MR) system. MATERIALS AND METHODS Phantom and in vivo studies were performed with a clinical 3T MR scanner. Accuracy and reproducibility of the SR T1 mapping using conventional and composite RF pulses(More)
To develop a prediction model to distinguish between transition zone (TZ) cancers and benign prostatic hyperplasia (BPH) on multi-parametric prostate magnetic resonance imaging (mp-MRI). This retrospective study enrolled 60 patients with either BPH or TZ cancer, who had undergone 3 T-MRI. We generated ten parameters for T2-weighted images (T2WI),(More)
To evaluate the feasibility of a 20 % reduced contrast dose hepatic arterial phase (HAP) CT for hypervascular hepatocellular carcinoma (HCC) with 100 kVp. The study included 97 patients with hypervascular HCC who underwent dynamic CT, including HAP scanning. The 54 patients had an estimated glomerular filtration rate (eGFR) of ≥60 were scanned with our(More)
AIM To perform an intra-individual investigation of the usefulness of a contrast medium (CM) and radiation dose-reduction protocol using single-source computed tomography (CT) combined with 100 kVp and sinogram-affirmed iterative reconstruction (SAFIRE) for whole-body CT (WBCT; chest-abdomen-pelvis CT) in oncology patients. MATERIALS AND METHODS(More)
The purpose of this study was to evaluate the feasibility of a contrast medium (CM), radiation dose reduction protocol for cerebral bone-subtraction CT angiography (BSCTA) using 80-kVp and sinogram-affirmed iterative reconstruction (SAFIRE). Seventy-five patients who had undergone BSCTA under the 120- (n = 37) or the 80-kVp protocol (n = 38) were included.(More)