Document Detail

Detection of myocardial perfusion abnormalities using ultra-low radiation dose regadenoson stress multidetector computed tomography.
MedLine Citation:
PMID:  21723516     Owner:  NLM     Status:  In-Data-Review    
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 A(2A)-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.
Amit R Patel; Joseph A Lodato; Sonal Chandra; Nadjia Kachenoura; Homaa Ahmad; Benjamin H Freed; Barbara Newby; Roberto M Lang; Victor Mor-Avi
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Publication Detail:
Type:  Journal Article     Date:  2011-06-12
Journal Detail:
Title:  Journal of cardiovascular computed tomography     Volume:  5     ISSN:  1876-861X     ISO Abbreviation:  J Cardiovasc Comput Tomogr     Publication Date:    2011 Jul-Aug
Date Detail:
Created Date:  2011-07-04     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101308347     Medline TA:  J Cardiovasc Comput Tomogr     Country:  United States    
Other Details:
Languages:  eng     Pagination:  247-54     Citation Subset:  IM    
Copyright Information:
Copyright © 2011 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.
University of Chicago, MC5084, 5841 S Maryland Ave, Chicago, IL 60637, USA.
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