Computed tomography angiography and perfusion to assess coronary artery stenosis causing perfusion defects by single photon emission computed tomography: the CORE320 study

Abstract

Aims: To evaluate the diagnostic power of integrating the results of computed tomography angiography (CTA) and CT myocardial perfusion (CTP) to identify coronary artery disease (CAD) defined as a flow limiting coronary artery stenosis causing a perfusion defect by single photon emission computed tomography (SPECT).

Methods and results: We conducted a multicentre study to evaluate the accuracy of integrated CTA-CTP for the identification of patients with flow-limiting CAD defined by ≥50% stenosis by invasive coronary angiography (ICA) with a corresponding perfusion deficit on stress single photon emission computed tomography (SPECT/MPI). Sixteen centres enroled 381 patients who underwent combined CTA-CTP and SPECT/MPI prior to conventional coronary angiography. All four image modalities were analysed in blinded independent core laboratories. The prevalence of obstructive CAD defined by combined ICA-SPECT/MPI and ICA alone was 38 and 59%, respectively. The patient-based diagnostic accuracy defined by the area under the receiver operating characteristic curve (AUC) of integrated CTA-CTP for detecting or excluding flow-limiting CAD was 0.87 [95% confidence interval (CI): 0.84-0.91]. In patients without prior myocardial infarction, the AUC was 0.90 (95% CI: 0.87-0.94) and in patients without prior CAD the AUC for combined CTA-CTP was 0.93 (95% CI: 0.89-0.97). For the combination of a CTA stenosis ≥50% stenosis and a CTP perfusion deficit, the sensitivity, specificity, positive predictive, and negative predicative values (95% CI) were 80% (72-86), 74% (68-80), 65% (58-72), and 86% (80-90), respectively. For flow-limiting disease defined by ICA-SPECT/MPI, the accuracy of CTA was significantly increased by the addition of CTP at both the patient and vessel levels.

Conclusions: The combination of CTA and perfusion correctly identifies patients with flow limiting CAD defined as ≥50 stenosis by ICA causing a perfusion defect by SPECT/MPI.

Keywords: Atherosclerosis; Imaging; Ischemia; Multislice computed tomography; Perfusion.

Figures

Figure 1

A complete CORE320 imaging data set for a 64-year-old male without prior history of coronary artery disease with chest pain symptoms. The left anterior descending coronary artery revealed a 96% diameter stenosis by computed tomography angiography (CTA) (Row A) and an 85% diameter stenosis by invasive coronary angiography (ICA) (Row B). The computed tomography myocardial perfusion (CTP) (Row C) study revealed a mild defect in the distal anteroseptal wall, and moderate defects in the basal anteroseptal, the basal anterior, the distal anterior, and apical walls, while the single photon emission computed tomography (SPECT) (Row D) study revealed moderate defects in the distal anterior, the distal anteroseptal, the basal anteroseptal and apical walls. The left circumflex artery revealed an 87% diameter stenosis by CTA, a 79% diameter stenosis by ICA, mild defects in the distal inferoseptal and distal inferolateral walls, and moderate defects in the distal anterolateral and distal anterior walls by CTP, and a moderate defect in the distal anterior wall by SPECT. The right coronary artery revealed a 60% diameter stenosis by CTA, a 77% diameter stenosis by ICA, a mild defect in the distal inferoseptal wall by CTP, and no myocardial perfusion defects by SPECT.

Figure 2

Patient flow. CT, computed tomography; SPECT, single photon emission computed tomography; ICA, invasive coronary angiography; CTA, computed tomography angiography; CTP, computed tomography myocardial perfusion; LAD, left anterior descending coronary artery; LCX, left circumflex coronary artery; RCA, right coronary artery. All invasive coronary angiography analysis performed using quantitative coronary angiography.

Figure 3

Receiver operating characteristic (ROC) curve and corresponding area under the curve (AUC) describing the diagnostic performance of combined computed tomography angiography (CTA) and computed tomography myocardial perfusion (CTP) to identify a ≥50% coronary stenosis and a corresponding myocardial perfusion using the reference standard of invasive coronary angiography (ICA) and single photon emission computed tomography myocardial perfusion imaging (SPECT/MPI) at a patient level.

Figure 4

Receiver operating characteristic (ROC) curve and corresponding area under the curve (AUC) describing the diagnostic performance of combined computed tomography angiography (CTA) and computed tomography myocardial perfusion (CTP) and CTA alone to identify a ≥50% coronary stenosis and a corresponding myocardial perfusion defect using the reference standard of invasive coronary angiography (ICA) and single photon emission tomography/myocardial perfusion imaging (SPECT/MPI) at a vessel level. (A) All vessels, (B) LAD, (C) LCX, and (D) RCA.