Adenosine-Stress Dual Energy CT Myocardial Perfusion Imaging with Second Generation DSCT: Correlation with Single-Photon Emission CT and Cardiac MRI

Purpose
To evaluate the accuracy of diagnosing myocardial perfusion defects with dual energy CT (DECT) using 2nd generation dual-source CT (DSCT).

Method and materials
Sixteen patients underwent three-phase contrast-enhanced ECG-gated DECT in adenosine-stressed, rest and delayed phases using a 2nd generation DSCT scanner (Flash, Siemens). The DECT data were used to map the myocardial iodine distribution within the left ventricular myocardium. All myocardial segments were classified as reversible or fixed perfusion defect or normal segment. Comparison of perfusion defects between stress-rest single-photon emission computed tomography (SPECT) and DECT was performed on a per-segment basis in all patients. In patients who also underwent stress-rest perfusion and delayed enhancement cardiac MRI (cMRI), perfusion defects on SPECT and DECT were compared with cMRI as the reference standard. Agreements between the imaging modalities for identifying the type of perfusion defect were calculated using Kappa statistics.

Results
Fifty six (20.6%) of 272 myocardial segments showed perfusion defects on SPECT with 28 reversible and 28 fixed perfusion defects. The Kappa value of agreement for identifying the type of perfusion defect was 0.822 (95% CI = 0.740–0.904) for DECT versus SPECT. Eighteen (17.6%) of 102 myocardial segments showed perfusion defects on cMRI with 4 reversible and 14 fixed perfusion defects. The Kappa value of agreement for identifying the type of perfusion defect was 0.785 (95% CI = 0.632–0.939) for SPECT versus cMRI and 0.871 (95% CI = 0.747–0.995) for DECT versus cMRI. Delayed-phase DECT detected abnormal myocardial delayed enhancement with 80.0% sensitivity, 100% specificity and 97.1% accuracy.

Conclusion
Our initial experience suggests that three phase contrast-enhanced DECT using 2nd generation DSCT might be promising for identifying different types of myocardial perfusion defects and is in excellent agreement with SPECT as well as with cMRI.

Clinical relevance/application
Compared with SPECT, DECT showed more accurate detection rates for reversible and fixed perfusion defects seen on cMRI, and revealed higher agreement for identifying the type of perfusion defect.

Submission Type: Scientific Presentations RSNA 2010

Authors: M Weininger, MD, Charleston, SC; B Ruzsics, MD, PhD; U J Schoepf, MD; G Bastarrika, MD; M A Rosenblum, MD; D Kang, MD