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Background: The ability of multidetector computed tomography (MDCT) to detect stress-induced myocardial perfusion abnormalities is of great clinical interest as a potential tool for the combined evaluation of coronary stenosis and its significance. However, stress testing requires repeated scanning that is associated with additional radiation exposure and iodine contrast. Objective: Our goal was to determine the effects of reduced tube voltage and contrast dose on the ability to detect perfusion abnormalities. Methods: We studied 40 patients referred for coronary CT angiography (CTA) who agreed to undergo additional imaging after administration of an A2A-agonist (regadenoson 0.4 mg). Images were acquired at rest and during hyperemia with prospective gating with 120 kV tube voltage with 80–90 mL of contrast in 20 patients (group 1) and 100 kV with 55–70 mL of contrast in the remaining 20 patients (group 2). Custom 3D analysis software was used to define 3D myocardial segments and measure x-ray attenuation in each segment. In each group of patients, myocardial attenuation was averaged for segments supplied by coronary arteries with stenosis causing >50% luminal narrowing on coronary CTA and separately for segments supplied by arteries without significant stenosis. Results: Coronary CTA detected stenosis >50% in 23 of 120 coronary arteries in 16 of 40 patients. In all patients combined, myocardial attenuation increased from 86 ± 9 at rest to 110 ± 17 HU with stress, reflecting an increase in tissue blood flow, despite the decrease in left ventricular cavity attenuation (347 ± 72 to 281 ± 55 HU), reflecting an increase in cardiac output. Importantly, in both groups, myocardial attenuation was equally reduced in segments supplied by diseased arteries (group 1: 119 ± 19 vs 103 ± 14 HU, P < 0.05; group 2: 108 ± 20 vs 97 ± 16 HU, P < 0.05), despite the 74% reduction in radiation (from 7.4 ± 2.8 to 1.9 ± 0.45 mSv) and the 28% reduction in contrast dose (from 84 ± 7 to 60 ±7 mL) (both P < 0.05). Conclusions: Regadenoson stress MDCT imaging can detect hypoperfused myocardium even when imaging settings are optimized to provide a significant reduction in radiation and contrast doses. [Copyright &y& Elsevier]

The article presents a study on the capability of S100A12, a small calcium binding protein, to mediate aortic wall and aortic aneurysm in the U.S. The study intends to determine the role of S100A12 in vascular smooth muscle cells (VSMC). The findings reveal on the capability of the S100A12 to activate the pathogenic pathways by modulating oxidative stress and vascular remodeling in vivo.

Summary: Background: Recent developments in 2D speckle tracking imaging allow not only measurements of regional myocardial strain, but also velocities of the mitral annulus. The aim of this study was to determine the accuracy of speckle tracking derived mitral annulus velocity compared with conventional pulsed wave Doppler measurements. Methods: 2D speckle tracking was acquired from the apical 4-chamber view (QLab, Speckle SQ, Philips, Andover, MA) in 169 subjects. While using texture tracking, two small regions of interest (ROIs) were placed in the septal (IVS) and lateral corners (LAT) of the mitral annulus. The software automatically tracked the ROIs frame-by-frame, yielding regional mean velocity curves of the mitral annulus throughout the cardiac cycle (synthetic pulsed wave Doppler; SPW). From these curves, peak systolic, early- and late-diastolic velocities of the mitral annulus (S′-SPW, E′-SPW, and A′-SPW) were measured. Peak systolic, early- and late-diastolic velocity in the mitral annulus (S′, E′, and A′) by conventional pulsed wave tissue Doppler tracing were also obtained. Results: Adequate ROI tracking was observed in 150/169 subjects in IVS and 139/169 subjects in LAT of the mitral annulus. All annular velocities derived from SPW were significantly lower than corresponding velocities obtained from conventional method in both IVS and LAT regions of the mitral annulus. However, significant correlation between S′ (E′, A′)-SPW and S′ (E′, A′) was observed. In particular, a good correlation between E′-SPW and E′ was noted in both IVS (r =0.89, P <0.001) and LAT (r =0.85, P <0.001) regions of the mitral annulus. If we defined E/E′-SPW in IVS>26 for predicting E/E′ in IVS>15, sensitivity, specificity, and accuracy were 83%, 97%, and 94%, respectively. E/E′-SPW in LAT>13 had a 94% sensitivity, 92% specificity, and 93% accuracy for predicting E/E′ in LAT>10. Conclusions: The values of annular velocities by SPW were significantly lower compared to those assessed by traditional tissue velocities. However, new cut-off values of E/E′-SPW for predicting elevated LV filling pressure highly correlated with traditional parameters. 2D speckle tracking imaging provides another strategy for evaluating LV filling pressures. [Copyright &y& Elsevier]