Abstract 2601: Comparison of Cardiac Magnetic Resonance imaging (CMRI) and SPECT for the Assessment of Flow Limiting Coronary Artery Stenoses
Cardiac magnetic resonance imaging (CMRI) is a rapid evolving method for the noninvasive assessment of symptomatic coronary artery disease (CAD). Single Photon Emission Computet Tomography (SPECT) is the widely used for the non-invasive assessment of CAD. Beyond morphological assessment by quantitative coronary angiography (CA) the pressure derived fractional flow reserve (FFR) is the well established gold standard to invasively evaluate the functional severity of coronary lesions. The aim of our study was to compare CMRI and SPECT for detection of flow limiting coronary stenoses compared to the invasive reference standard FFR.
Methods: 40 Patients with suspected CAD received a CMRI (Siemens Sonata, Erlangen, GE; IPAT) and SPECT (Philips Prism 3000 XP, Cleveland, Ohio; 700MBq) within two weeks of the scheduled CA. Signal intensity curves of the first pass of a Gadolineum-DTPA bolus at rest and during hyperemia (Adenosine 140μg/kg/min i.v.) were investigated and input function corrected signal intensitiy curve’s upslope (US) was determined to calculate the myocardial perfusion reserve index (MPRI= US stress /US rest) for each perfusion territory. A MPRI <1.5 was considered positive. For the SPECT analysis the summed stress score (SSR), the summed rest score (SRS) and summed difference score (SDS) were calculated. If during CA the FFR measurement (Pressure Wire, Radi, SE) was <0.75 the lesion was defined as hemodynamically significant. All other lesions were defined as normal.
Results: 120 perfusion areas (40 LAD; 40 LCx and 40 RCA) were evaluated. 99 (83%) areas were normal by FFR and 21 (17%) areas showed hemodynamically significant stenoses. Using the ROC analysis CMRI provided the best test characteristics (AUC: 0.92) followed by SSR (AUC:0.79) SDS (AUC:0.72) and SRS (AUC: 0.69). CMRI and SSR revealed a sensitivity of 86% [63%–96%] and 72%[47%– 88%]. Specificity was 89% [80%–94%] and 91% [83%–95%].
Conclusion: This study demonstrates the ability of CMRI and SPECT to identify perfusion territories with hemodynamically significant coronary stenoses with high sensitivity and specificity. The overall accuracy of CMRI was comparable to SPECT without the burden of radiation.