Evaluation of Stress Dynamic CT Myocardial Perfusion Imaging in Diagnosing Myocardial Ischemia

Objective To evaluate stress dynamic load myocardial perfusion imaging( MPI) using 128-row dual-source CT scanner in diagnosing myocardial ischemia. Methods Thirty patient with clinically-suspected or confirmed coronary artery disease were included in this study. Stress dynamic MPI with 128-row dual-source CT scanner was performed in all patients. The myocardial blood flow( MBF) value was determined. Taking SPECT-MPI as the reference standard,the sensitivity,specificity,positive predictive value( PPV) and negative predictive value( NPV) of CT-MPI in the diagnosis of myocardial perfusion defect were evaluated,and the consistency with the diagnosis of SPECT-MPI was analyzed. Results Technical success was achieved in all 30 cases. The mean MBF value of all segments was( 99. 11 ± 31. 89) ml·100ml- 1·min- 1; the MBF values of non-ischemic area and ischemic area were( 117. 61 ± 29. 82) ml·100ml- 1·min- 1and( 80. 60 ± 22. 15) ml·100ml- 1·min- 1respectively,the differences were statistically significant( t = 15. 764,P 0. 001). In 19 cases receiving CT-MPI examination,myocardial perfusion defect was observed in 26 vascular perfusion areas; and segment-based perfusion defect was revealed in 52 segments. SPECT-MPI detected abnormal myocardial perfusion in 13 patients,including 16 abnormal vascular perfusion areas with 34 myocardial segments in total. Compared with SPECT-MPI,the sensitivity,specificity,PPV and NPV of CT-MPI in detecting myocardial ischemia were 92. 31%( 12 /13),58. 82%( 10 /17),63. 16%( 12 /19) and 90. 91%( 10 /11) respectively,the accuracy was 73. 33%. The consistency between CT-MPI and SPECT-MPI was evaluated with Kappa analysis,and Kappa value was 0. 485( P 0. 005).Based on the vascular perfusion area and on the myocardial segment,the sensitivity,specificity,PPV and NPV of CT-MPI in detecting myocardial ischemia were 93. 75%( 15 /16),85. 14%( 63 /74),57. 69%( 15 /26),98. 44%( 63 /64) respectively and 94. 12%( 32 /34),95. 80%( 456 /476),1. 54%( 32 /52),99. 56%( 456 /458) respectively,with the diagnostic accuracy being 86. 67% and 95. 69% respectively. The Kappa values of diagnostic consistency between CT-MPI and SPECT-MPI was 0. 634 and 0. 772 respectively( both P 0. 001). Conclusion Stress dynamic CT-MPI can effectively detect myocardial perfusion defects,which is very helpful in evaluating myocardial ischemia.