SPECT Myocardial Perfusion Reserve in Patients with Multivessel Coronary Disease: Correlation with Angiographic Findings and Invasive Fractional Flow Reserve Measurements

Abstract

Quantification of myocardial perfusion reserve (MPR) is an emerging topic in nuclear cardiology with an expected diagnostic and prognostic incremental value, especially for patients with severe coronary artery disease. The advent of new dedicated solid-state cameras has opened new perspectives for perfusion quantitation in SPECT. We appraised the feasibility of perfusion reserve estimation using a cadmium zinc telluride camera in a cohort of multivessel patients and its pertinence with respect to angiographic data. Methods: Twenty-three patients with known multivessel coronary artery disease were prospectively enrolled. Dynamic SPECT acquisitions using 99m Tc-tetrofosmin at rest and after vasodilator stress were performed using a dedicated cadmium zinc telluride camera. Reconstructed frames were automatically segmented to extract the vascular input function and the myocardial uptake curve. Onecompartment kinetic modeling was used to estimate global and regional uptake values, and then myocardial blood flow was derived using the Renkin-Crone equation. Global and regional MPR was assessed using flow difference (stress − rest) and flow ratio (stress/rest). All patients underwent control coronary angiography within 4 wk, which served as the reference for MPR index assessment. Relevant angiographic findings included maximal stenosis and (for a subgroup of 26 vessels) invasive measurement of fractional flow reserve (FFR). A stenosis was considered obstructive if greater than 50% and an FFR abnormal if lower than 0.8. Results: Global MPR correlated well with number of obstructed vessels (P , 0.001). After multivariate analysis, both regional flow ratio and flow difference were significantly associated with maximal stenosis (P , 0.001) and FFR (P , 0.001). Regional MPR indices were significantly different in obstructed and nonobstructed vessels (P , 0.001) and in vessels with normal and abnormal FFR (P , 0.001). With a cutoff of 2, the sensitivity, specificity, and accuracy of regional flow ratio were, respectively, 80%, 85%, and 81% for the detection of obstructed vessels and 89%, 82%, and 85% for the detection of abnormal FFR. Conclusion: Scintigraphic estimations of global and regional MPR in multivessel patients using a cadmium zinc telluride camera appear to correlate well with invasive angiographic findings, including maximal stenosis and FFR measurements.

Diagnostic Utility of Quantifying Myocardial Flow Reserve with ^99mTc-Sestamibi Dynamic SPECT Using a Standard Dual-Head SPECT Camera

“…We compared the global mean MFR of 1 vessel disease to those of 2-3 vessel disease patients. The MFR of 1 vessel disease patients was significantly higher than that of multi vessel disease, which was compatible with earlier studies (12,20). In this study, 10 of the CAD group (n=25) had a history of CABG, and 5 of the CAD group had a history of myocardial infarction with fixed perfusion defects in the SPECT, which may affect significantly to the MFR values and complicated the results.…”

Absolute myocardial blood flow vs relative myocardial perfusion: Which one is better?

“…16 Both global and regional MPR correlated with angiographic coronary stenosis and invasive FFR among patients with multivessel coronary artery disease. 17 Combining dynamic CZT-SPECT imaging with CT attenuation correction allows assessment of absolute MBF and MFR. In a porcine model, Wells et al 18 demonstrated the feasibility of MBF assessment using a dedicated cardiac CZT camera and CT-based attenuation and scatter correction.…”

Combined assessment of myocardial perfusion and left ventricular function by nuclear cardiology: The value of high-efficiency SPECT

“…19 Another PET-like quality, recently attributed to CZT-MPI is the feasibility to perform dynamic tomographic imaging, and quantify a myocardial perfusion reserve index, representing the ratio of peak myocardial blood flow to resting myocardial blood flow. 20,21 This measurement has the potential to increase the sensitivity of MPI in detecting extensive CAD when relative perfusion is normal due to balanced hypoperfusion, and reduced flow heterogeneity. A new PET-like performance of CZT technology is shown in the present study by Brodov et al, demonstrating the feasibility of measuring the EF reserve by short, successive acquisitions, starting 5 minutes after regadenoson injection, and detecting a negative, early EF reserve among ischemic patients, compared to a positive EF reserve among nonischemic patients.…”