Topic
Perfusion scanning
About: Perfusion scanning is a research topic. Over the lifetime, 9496 publications have been published within this topic receiving 223860 citations. The topic is also known as: perfusion imaging.
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TL;DR: In patients with suspected CAD obstructive disease can be excluded in 53% of patients by coronary CTA, and these patients have good outcome, and about one-half of the remaining patients have normal perfusion and event rate comparable to patients without obstructive CAD on coronary CTA while patients with ischemia have clearly worse outcome.
Abstract: Objectives The purpose of this study was to evaluate the prognostic value of sequential hybrid imaging strategy in which positron emission tomography (PET) perfusion imaging is performed selectively in patients with suspected obstructive coronary artery disease (CAD) on coronary computed tomography angiography (CTA). Background Coronary CTA is an accurate diagnostic test for excluding obstructive CAD. However, the positive predictive value is suboptimal. Methods We investigated 864 consecutive symptomatic patients with intermediate probability of CAD who adhered to the sequential imaging approach. PET myocardial perfusion imaging using 15O-labeled water during adenosine stress was performed when suspected obstructive stenosis was present on coronary CTA. The major adverse events (AEs) including all-cause mortality, myocardial infarction (MI), and unstable angina pectoris (UAP) were recorded. Results During a median follow-up of 3.6 years, 16 deaths, 10 MIs, and 5 UAPs occurred. Obstructive CAD was excluded by coronary CTA in 462 (53%) patients who had significantly lower annual AE rate than did patients with suspected obstructive stenosis on coronary CTA (0.4% vs. 1.5%; p = 0.003). The latter underwent PET study, on which 195 (49%) had normal and 207 had abnormal perfusion. The annual rate of AEs was 5 times higher in those with abnormal perfusion than with normal perfusion (2.5% vs. 0.5%; p = 0.004). Patients with normal perfusion had AE rate comparable to patients without obstructive CAD on coronary CTA (p = 0.77). Conclusions In patients with suspected CAD obstructive disease can be excluded in 53% of patients by coronary CTA, and these patients have good outcome. About one-half (49%) of the remaining patients have normal perfusion and event rate comparable to patients without obstructive CAD on coronary CTA while patients with ischemia have clearly worse outcome. Sequential approach utilizing anatomical imaging by coronary CTA followed by selective functional perfusion imaging is a feasible strategy to diagnose and risk-stratify patients with suspected CAD.
62 citations
TL;DR: This study tested the hypothesis that coronary artery disease might be identified by a decrease in Doppler measurements of flow velocity and acceleration by assessing the response of aortic blood flow velocity to exercise in patients who underwent continuous wave Dopplers echocardiographic examination before, during and immediately after near maximal treadmill exercise.
62 citations
TL;DR: Fractal analysis of the spatial distribution of perfusion was performed and it was demonstrated that the fractality of this distribution exists even in microscopic dimensions, implying that parameters of the fractal distribution depend on the microvascular tone rather than on anatomic preformations.
Abstract: —The fractal nature of heterogeneity of myocardial blood flow and its implications for the healthy and diseased heart is not yet understood. The main hindrance for investigation of blood flow heterogeneity and its role in physiology and pathophysiology is that conventional methods for determination of myocardial perfusion have severe limitations concerning temporal and spatial resolution and invasiveness. In isolated rat hearts, we developed a nuclear magnetic resonance technique that does not depend on contrast agents and in which the apparent longitudinal relaxation time is made perfusion sensitive by selective preparation of the imaging slice. This perfusion-sensitive relaxation time is determined within 40 seconds as a map with a high spatial in-plane resolution of 140×140 μm 2 and a thickness of 1.5 mm. Perfusion imaging was validated with the established microsphere technique. Additionally, the congruence between perfusion-sensitive T 1 maps and first-pass perfusion imaging was demonstrated. As an application of high-resolution perfusion imaging, fractal analysis of the spatial distribution of perfusion was performed. We were able to demonstrate that the fractality of this distribution exists even in microscopic dimensions. Vasodilation by nitroglycerin modulated the fractal pattern of perfusion, and the decrease of the fractal dimension indicated a shift toward homogeneity. This implies that parameters of the fractal distribution depend on the microvascular tone rather than on anatomic preformations; ie, fractality is a functional characteristic of perfusion.
62 citations
TL;DR: ASL findings in patients with acute stroke and TIA are discussed, focusing on typical appearances, common artifacts, and comparisons with PWI.
61 citations
TL;DR: Noninvasive measurements of cerebral ICG kinetics by NIRS provide a useful means of detecting cerebral perfusion deficits in patients with acute stroke, which correlate well with those obtained by PWI.
Abstract: Background: In acute stroke patients, there is a need for noninvasive measurement to monitor blood flow-based therapies. We investigated the utility of near-infrared spectroscopy (N
61 citations