Contrast-enhanced cardiac MDCT, stress MRI help detect perfusion abnormalities
CHICAGO—Adenosine stress multidetector CT (MDCT) myocardial perfusion imaging can be successfully performed in patients with coronary artery disease (CAD), proving to have good agreement with stress myocardial perfusion MRI, according to research presented Tuesday during a scientific session at the 94th annual meeting of the Radiological Society of North America (RSNA).

According to the authors, stress myocardial perfusion imaging using contrast-enhanced MDCT might be of great value in detecting myocardial ischemia in patients with CAD. The aim of the study, presented by Shingo Kato, MD, Research Center Hospital for Charged Particle Therapy, National Institute of Radiological Sciences in Chiba, Japan, was to compare MDCT myocardial perfusion imaging and stress myocardial perfusion MRI for the detection of perfusion abnormality during stress.
The study protocol was approved by the institutional review board and all participants gave written, informed consent. Cardiac CT was performed in 13 patients by using a 64-detector MDCT scanner. Prior to the CT study, investigators administered beta-blockers to the patients.

During continuous injection of adenosine, contrast-enhanced cardiac CT images were acquired with retrospectively gated helical MDCT protocol. Images were reconstructed with beam-hardening correction and total radiation dose during CT study was less than 20mSv. The researchers performed adenosine stress myocardial perfusion MRI within two weeks from CT perfusion study in nine patients. Both stress myocardial perfusion MDCT and MR images were qualitatively assessed by two observers using a 16-segment model, according to Kato.
He said they discovered that all patients completed stress MDCT study protocol without significant side-effects. The averaged heart rate in 13 patients was 62 ± 12 beats/min at rest and 70 ± 12 beats/min during adenosine stress. Perfusion abnormality during stress was observed in 57 (40 percent) of 144 segments by MDCT and in 55 (38 percent) of 144 segments by MRI, the authors wrote.

On a vessel-based analysis, stress CT and stress MRI findings were concordant in 23 (85 percent) of 27 territories. The sensitivity, specificity and accuracy of adenosine stress myocardial perfusion CT imaging for the detection of abnormal perfusion on stress first-pass contrast enhanced MRI was 88 percent, 80 percent and 85 percent, respectively.
Kato said that the clinical relevance of the study results suggest that the “ability of MDCT to perform both stress perfusion imaging and coronary angiography will significantly enhance the value of cardiac MDCT study in the diagnosis and treatment of patients with CAD,” the wrote.