Sung Min Ko, Presenter: Nothing to Disclose

Jeong Geun Yi MD, Abstract Co-Author: Nothing to Disclose

Youngjun Kim MD, Abstract Co-Author: Nothing to Disclose

Na-Mi Choi, Abstract Co-Author: Nothing to Disclose

Hyunwoo Chung, Abstract Co-Author: Nothing to Disclose

To evaluate the feasibility of dual-energy CT (DECT) for diagnosing myocardial ischemia without adenosine stress compared with SPECT-myocardial perfusion imaging (MPI) and CT angiography (CTA)

A total of 60 patients with suspected or known coronary artery disease underwent retrospectively ECG-gated DECT of the heart. DECT was performed by independently operating the two tubes of a dual-source CT system at high (140kV) and low (80kV) energy x-ray spectra settings. CTA studies for stenosis detection were reconstructed based on mixed x-ray spectra. DECT image analysis was performed by mapping the myocardial iodine content distribution based on high and low energy X-ray spectra and superimposing color coded iodine maps onto multiplanar reconstructions of the myocardium in long- and short-axis views. Myocardial blood-pool deficit was evaluated by two radiologists in consensus using AHA 17 segment model and 3 major coronary artery territories. Patients with infarcted myocardium (thinned myocardium with fixed perfusion defect or fat infiltration) were excluded in this study. Results were compared with SPECT-MPI and CTA.

A total of 833 myocardial segments and 147 coronary artery territories of 49 patients (35men, 14 women; mean age 59 years) were evaluated. The mean heart rate of the patients was 61.5±8.6 b.p.m. The mean patient radiation dose was 6.9±1.8 mSv. Totally 112 segments and 28 territories in 16 patients showed blood-pool deficits on DECT. The sensitivity, specificity, accuracy, positive and negative predictive value of DECT for detecting ischemic myocardial territories (segments) were 70% (62%), 85% (87%), 84% (86%), 25% (7%), and 97% (98%) compared with SPECT-MPI and 60%, 85%, 79%, 47%, and 95% compared with CTA. False positive segments and territories mimicking blood-pool deficits on DECT were related to beam hardening artifacts, inhomogeneous areas of normal myocardial perfusion, and cardiac motion artifact due to the low temporal resolution of DECT.

DECT without phamarcological stress may be not feasible to diagnose myocardial perfusion deficits compared to SPECT-MPI as the reference standard.  Further researches are required to determine the diagnostic value of this DECT technique.

Further studies are required to determine, whether dual-energy CT enables assessment of the myocardial ischemia without adenosine stress.

Ko, S, Yi, J, Kim, Y, Choi, N, Chung, H, Dual-energy Cardiac CT for Diagnosing Myocardial Ischemia: Correlation with SPECT-Myocardial Perfusion Imaging and CT Angiography.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8015001.html