An x-ray radiographic system consisting of two detectors in tandem, or a sandwich detector, can produce dual-energy image from a single-shot exposure. Subtraction of two images obtained from the two detectors can produce a sharper image through an unsharp masking effect if the two images are formed at different spatial resolutions. This is indeed possible by incorporating different thicknesses of x-ray conversion layers in the detectors. In this study, we have developed a microtomography system with a sandwich detector in pursuit of high-resolution bone-enhanced small-animal imaging. The results show that the bone-enhanced images reconstructed from the dualenergy projection data provide higher visibility of bone details than the conventionally reconstructed images. The microtomography with the single-shot dual-energy sandwich detector will be useful for the high-resolution bone-enhanced small-animal imaging. K : Computerized Tomography (CT) and Computed Radiography (CR); Medical-image reconstruction methods and algorithms, computer-aided diagnosis 1Corresponding author.

For a dedicated x-ray inspection of printed-circuit boards (PCBs), a bench-top planar cone-beam computed tomography (pCT) system with a flat-panel detector has been built in the laboratory. The system adopts the tomosynthesis technique that can produce cross-sectional images parallel to the axis of rotation for a limited angular range. For the optimal operation of the system and further improvement in the next design, we have evaluated imaging performances, such as modulation-transfer function, noise-power spectrum, and noise-equivalent number of quanta. The performances are comparatively evaluated with the coventional cone-beam CT (CBCT) acquisition for various scanning angular ranges, applied tube voltages, and geometrical magnification factors. The pCT scan shows a poorer noise performance than the conventional CBCT scan because of less number of projection views used for reconstruction. However, the pCT shows a better spatialresolution performance than the CBCT. Because the image noise can be compensated by an elevated exposure level during scanning, the pCT can be a useful modality for the PCB inspection that requires higher spatial-resolution performance. K : Computerized Tomography (CT) and Computed Radiography (CR); Inspection with x-rays 1Corresponding author.

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Background: There have been only a few studies investigating the association between arterial stiffness and acute cerebral small vessel disease (SVD), which showed conflicting results. Objective: The aim of this study was to determine the association of brachial-ankle pulse wave velocity with acute SVD. Patients and Methods: We identified 1145 consecutive patients with acute ischemic stroke who underwent both MR imaging and brachial-ankle pulse-wave velocity (baPWV) measurement. The association between baPWV and acute SVD was tested using linear and logistic regression analyses. This study was approved by the local institutional review boards. Results: Mean age of patients was 68 (±12) years. Mean baPWV levels were 20.7 (±5.1) m/s in patients with large artery atherosclerosis, 20.7 (±4.9) m/s in patients with cardioembolism, 21.3 (±5.2) m/s in patients with small vessel occlusion, 17.8 (±6.3) m/s in patients with other determined etiology, and 20.2 (±5.1) m/s in patients with undetermined etiology. On bivariate analysis, a 1-SD increase in baPWV was associated with acute small vessel occlusion (OR, 1.16; 95% CI, 1.02-1.32). The association remained significant even after adjustment for confounders. Conclusion: baPWV is associated with acute SVD. Our findings suggest that arterial stiffness is linked to the pathogenesis of SVD. In future trials, it should be tested whether arterial stiffness can be a therapeutic target for SVD.