Abstract 11278: Diagnostic Performance of Combined 320-detector Computed Tomography Coronary Angiography and Adenosine Stress Myocardial Perfusion Imaging: A Pilot Study

Abstract

Background: Computed tomography coronary angiography (CTA) is established for the non-invasive diagnosis of coronary artery disease (CAD), however in its current form CTA is limited in detecting myocardial ischemia. We sought to determine whether adenosine stress CT myocardial perfusion imaging (CTP), when added to CTA, detected perfusion abnormalities caused by obstructive CAD.

Methods: Twenty patients (age 66±9 years, 65% male) with no known CAD but abnormal single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) underwent prospectively-gated adenosine stress 320-detector CTP and CTA, as well as invasive coronary angiography (ICA) within 60 days of SPECT-MPI. A blinded interventional cardiologist evaluated ICA images. A blinded nuclear physician analysed SPECT-MPI images for fixed and reversible perfusion defects. CTP and CTA studies were assessed qualitatively by consensus between two blinded cardiologists. Vessels/territories with both >50% stenosis on ICA and corresponding perfusion defect on SPECT-MPI were defined as ischaemic and formed the reference standard against which combined CTP and CTA were compared.

Results: All patients successfully completed the CT protocol with diagnostic image quality (60 vessels/territories available for analysis). 16 vessels/territories (27%) were ischaemic by combined ICA and SPECT-MPI criteria. Sensitivity, specificity, positive predictive value and negative predictive value for combined CTP and CTA was 94%, 96%, 88%, and 98% respectively on a per-vessel/territory basis. Mean combined CTP and CTA radiation dose was 9.2±6.1mSv compared to 13.2±2.2mSv for SPECT-MPI (p=0.06).

Conclusions: Combined 320-detector CTP and CTA is accurate in identifying obstructive CAD causing perfusion abnormalities when compared with combined ICA and SPECT-MPI. This is achieved with acceptable radiation dose, comparable to SPECT-MPI.