Abstract 4178: Adenosine Induced Stress Myocardial Perfusion Imaging using Dual Source Cardiac CT:Initial Clinical Experience

Abstract

Intro : The feasibility and accuracy of performing a comprehensive CT exam incorporating coronary, stress and rest perfusion, and delayed enhancement (DE) imaging is unknown. Our goal was to determine the feasibility of stress DSCT in identifying and quantifying the extent of ischemic and infarcted myocardium as compared to nuclear myocardial perfusion imaging (MPI) and invasive angiography (IA). Methods : 12 consecutive pts who had a prior MPI & subsequently underwent IA were included in study. DSCT (2×32×.6) performed as follows: Stress CT (SCT) - retrospectively gated scan with tube current modulation and pitch adaptation obtained 3 min post adenosine (.14 mg/kg/min) with Isovue @ 4 –5 ml/s; Rest CT (RCT) - non-helical prospective scan, Isovue @ 4 –5 ml/s; DE Scan - prospective acquisition 7 min post RCT, 100kV. CT perfusion, CT angiography (CTA), MPI, and IA were each read blinded to results of other tests. For DSCT & MPI, perfusion defect (pd) severity & reversibility were scored for ea. of the 17 segments. CT interpretation used 10mm multi planar reformation in short axis. Per vessel results of SCT were compared to the following references S-MPI IA≥50% IA≥70% CTA severe stenosis & S-MPI & IA≥50. Results : Protocol was successfully completed for all 12 pts (44±11 yrs; 10 males; BMI 31.5±7 kg/m 2 ) 11/12 pts had prior CAD; 5/12 had a prior MI and 3/12 had a prior PCI. Total contrast dose was 151cc; Average radiation dose of protocol 13mSv (8.8, 2.8, and 1.3mSv for SCT, RCT, and DE respectively). Average HR was 71 for RCT & 80 for SCT. Out of 204 segments (17×12pts), RCT pd were identified in 39 (5tr=transmural), SCT pd in 86 (40tr) and DE in 22 (3tr). S-MPI pd were present in 66 segments. Per vessel analysis: IA>70% lesions in 19/36, SCT identified pd in 25/36 and S-MPI in 21/36. Compared to MPI, SCT had a sensitivity (Sn) of 91% & specificity (Sp) of 43%. When IA>70%, used as the reference the Sn & Sp were: 79 & 41% for SCT, 63 & 47% for S-MPI, 89 & 65% for CTA, and 84 & 71% when abnormal on both CTA & SCT (p=NS). Conclusions : Adenosine stress CT can accurately identify both anatomical stenosis as well as reversible and nonreversible perfusion defects. The role of stress CT is unknown at this time and larger datasets will be necessary for accurate comparison with nuclear MPI.