Dynamic, Quantitative Myocardial Stress CT Perfusion Imaging: Initial Clinical Experience
Purpose
To evaluate the feasibility of adenosine-stress myocardial perfusion imaging using 128-slice dual-source CT for the qualitative and quantitative assessment of myocardial blood flow (MBF) compared to stress perfusion and viability MRI.
Method and materials
20 patients (6 female; mean age 60±11 years) underwent a standardized cardiac CT (Definition Flash, Siemens) protocol consisting of prospectively ECG-triggered coronary CT angiography, dynamic adenosine-stress myocardial perfusion imaging using a “shuttle” mode, and delayed enhancement acquisitions. In the shuttle mode, data are acquired during every other RR interval at two alternating table positions with ECG-triggering, with the table shuttling back and forth between the two positions during image acquisition. In addition all patients underwent stress/rest perfusion and delayed-enhancement MRI. Two independent observers visually assessed myocardial perfusion defects in a blinded fashion. For semi-quantitative evaluation, CT- and MRI-derived myocardial-to-left ventricular upslope indices were compared. Additionally, absolute MBF was quantified based on dynamic perfusion CT and correlated with semi-quantitative CT measurements. Statistical analysis used paired t tests, Wilcoxon signed-rank test, linear correlation, and Bland-Altman statistics.
Results
A total of 303 segments (89%) were suitable for evaluation. Sensitivity, specificity, positive and negative predictive values for detecting myocardial perfusion defects at CT compared to MRI were as follows: 86%, 98%, 93%, 94%. Semi-quantitative analysis of CT data detected differences between ischemic and non-ischemic myocardium with a signal intensity upslope comparable to MRI-derived values (CT: 5.2±2 SI/s; MRI: 4.7±2.3 SI/s). Moderate correlation was observed between absolute CT quantification of myocardial blood flow and semi-quantitative CT measurements. Mean total dose length product for the entire cardiac CT protocol was 1290±233mGy*cm.
Conclusion
Adenosine-stress first pass myocardial CT perfusion imaging enables the evaluation of qualitative and semi-quantitative parameters of myocardial perfusion in a comparable fashion as MRI and may enable absolute quantification of the myocardial blood flow.
Clinical relevance/application
CT may have potential for the integrative assessment of all aspects of coronary artery disease including coronary artery morphology, cardiac function, perfusion, and viability with a single modality.
Submission Type: Scientific Presentations RSNA 2010
Authors: M Weininger, MD, Charleston, SC; U J Schoepf, MD; D Kang, MD; G W Rowe, DSc; P Costello, MD; G Bastarrika, MD
