Detection of myocardial perfusion abnormalities using ultra-low radiation dose regadenoson stress multidetector computed tomography

作者：Patel Amit R; Lodato Joseph A; Chandra Sonal; Kachenoura Nadjia; Ahmad Homaa; Freed Benjamin H; Newby Barbara; Lang Roberto M; Mor Avi Victor^*

来源：Journal of Cardiovascular Computed Tomography, 2011, 5(4): 247-254.

DOI：10.1016/j.jcct.2011.06.004

• Cardiovascular CT
• Multidetector CT
• Perfusion
• Myocardium

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.

• 出版日期2011-8