Diagnostic efficiency of quantification of myocardial blood flow and coronary flow reserve with CZT dynamic SPECT imaging for patients with suspected coronary artery disease: a comparative study with traditional semi-quantitative evaluation

Abstract

Background: Myocardial blood flow (MBF) quantitation with cadmium-zinc-telluride (CZT) dynamic single-photon emission computed tomography (SPECT) is being increasingly investigated toward clinical utilization.

Methods: In this prospective study, forty-nine patients with suspected or known coronary artery disease (CAD) underwent a rest/adenosine triphosphate (ATP) stress dynamic and routine gated myocardial perfusion imaging (MPI) by CZT SPECT and then received coronary angiography (CAG). Quantitative diagnosis from the dynamic SPECT and a flow diagram was automatically obtained by the dedicated software and compared with the result of semi-quantitative analysis with gated MPI using the angiographic stenosis as the reference standard.

Results: When stenosis ≥50% was considered at the participant level, the sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) and accuracy (AC) of the quantitative diagnosis were higher than semi-quantitative method as (84.4% vs. 65.6%, 88.2% vs. 70.6%, 93.1% vs. 80.8%, 75.0% vs. 52.2%, 85.7% vs. 67.3%) (all P<0.05). The receiver operating characteristic (ROC) curve analysis generated the optimal critical value as 1.86 and 1.61 mL/min/g for stress MBF (sMBF) and MFR, respectively. The diagnosis performance of the quantitative diagnosis was higher than semi-quantitative method as (78.9% vs. 68.4%, 63.3% vs. 60.0%, 57.7% vs. 52.0%, 82.6% vs. 75.0%, 69.4% vs. 63.3%) for the criteria of ≥75% stenosis on CAG (all P<0.05) with optimal critical values as 1.71 and 1.15 mL/min/g. There was no significant difference between sMBF and MFR.

Conclusions: The diagnostic efficiency by using the quantitative method of CZT dynamic SPECT imaging is superior to traditional semi-quantitative gated MPI for the diagnosis of CAD, which improved the diagnostic specificity and accuracy when the critical was stenosis ≥50%.

Keywords: Cadmium-zinc-telluride (CZT); coronary artery disease (CAD); diagnostic efficiency; myocardial blood flow (MBF); single-photon emission computed tomography (SPECT).

Figure 1

A 76-year-old man with untypical angina and smoking history, without high blood pressure, hyperlipidemia and diabetes. Routine gated MPI with ATP stress and rest test was not conclusive and underestimated the extend and severity of ischemia, which was mildly abnormal (SSS =5, SRS =0, SDS =5), while quantitative diagnosis with dynamic data was quite sure of abnormal results and showed very severe ischemia in a large area of left ventricular myocardium, and LV-MFR and sMBF were both severely reduced. Finally, invasive CAG showed that it was a case with triple-vessel, multiple and severely stenotic lesions (the majority of stenosis ≥80%) in coronary arteries which was an indication of coronary artery bypass grafting (CABG). (A) Routine ATP stress plus rest serial tomographic images. (B) Dynamic analysis with MyoFlowQ for this patient: including quantitative diagnosis by MyoFlowQ and quantitative parameters (sMBF, rMBF and MFR) obtained by this software. (C) Invasive CAG: multiple severely stenotic lesions in LAD, LCX and RCA (white arrows).

Figure 2

A 60-year-old woman complained of shortness of breath for nearly 4 years, with known hypertension and diabetes history for more than 10 years, and she had no typical angina and hyperlipidemia. Routine ATP stress and rest images were almost normal (including SSS, SRS and SDS), and no TID or decreased stress LVEF, while quantitative data showed very severe ischemia in a large area in the territory of LAD and LCX, and both LV-MFR and sMBF were severely reduced. Followed invasive CAG showed multiple narrowed lesions in three vessels. (A) Routine ATP stress plus rest serial tomographic images. (B) Dynamic analysis with MyoFlowQ for this patient: including quantitative diagnosis by MyoFlowQ and quantitative parameters (sMBF, rMBF and MFR) obtained by this software. (C) Invasive CAG: 80% stenosis in the proximal LAD,90% stenosis in the remote segment in LCX, and 90% stenosis in the proximal RCA and opening of the posterior descending branch (PLV).

Figure 3

ROC curves of LV-sMBF, LV-MFR, SSS, SDS for the diagnosis of CAD (stenosis ≥50% as the case standard on CAG at participate level). The AUC of LV-sMBF, LV-MFR, SSS, SDS was 0.88, 0.82,0.65,0.68, respectively. The optimal critical value for LV-sMBF was 1.86 mL/min/g, and the SN and SP were 81.2% and 87.9%, respectively. The optimal critical value for LV-MFR was 1.61, and the SN and SP were 81.2% and 69.7%, respectively. The optimal critical value for SSS was 8, and the SN and SP were 30.3% and 100%, respectively. The optimal critical value for SDS was 3, and the SN and SP were 45.5% and 81.2%, respectively. There was no statistical significance for AUC between LV-sMBF and LV-CFR (Z=1.78, P=0.08).

Figure 4

ROC curves of LV-sMBF, LV-MFR, SSS, SDS for the diagnosis of CAD (stenosis ≥ 75% as the case standard on CAG at participate level). The AUC of LV-sMBF, LV-MFR, SSS, SDS was 0.80, 0.75, 0.70, 0.72, respectively. The optimal critical value for LV-sMBF was 1.71 mL/min/g, and the SN and SP were 90.0% and 65.5%, respectively. The optimal critical value for LV-MFR was 1.15, and the SN and SP were 50.0% and 93.1%, respectively. The optimal critical value for SSS was 5, and the SN and SP were 60.0% and 79.3%, respectively. The optimal critical value for SDS was 5, and the SN and SP were 60.0% and 82%, respectively. There was no statistical significance for AUC between LV-sMBF and LV-CFR (Z=1.34, P=0.18).