3D CMR comparable to MPS for estimating ischemic burden

3D myocardial perfusion cardiovascular magnetic resonance MR (CMR) adds depth to looking at ischemic burden in heart patients, according to a recently published study. It one day may serve as an alternative to imaging techniques that rely on ionizing radiation.

Researchers at the Royal Brompton Hospital in London performed a comparative analysis between 3D CMR and 99mTc-tetrofosmin myocardial perfusion scintigraphy (MPS) on the ischemic load of 45 patients referred for MPS. Their study assessed patients using both 3D CMR perfusion imaging and MPS to determine the accuracy of predicting ischemic burden.

In 38 of 45 patients, the two methods agreed for the presence or absence of inducible ischemia. The average bias for ischemic burden between MPS and 3D CMR was -0.62 percent. MPS and CMR also agreed on the presence or absence of myocardial scarring in 84 percent of patients.

The average ischemic burden according MPS in all 45 patients was 7.5 percent. The CMR average ischemic burden was 6.8 percent. No significant differences between methods were reported.

Researchers also calculated burden via three short axis slices taken from the 3D CMR images and compared them with SPECT measurement to determine how they fared against a whole heart analysis. The 2D images were reviewed independently. This produced a lower mean ischemic burden, at about 5.7 percent. Researchers noted the best correlation between the analysis of whole heart CMR ischemic burden and MPS.

First author Roy Jogiya, MBBS, of British Heart Foundation’s Center for Excellence at King’s College, et al noted, however, “Only an adequately powered head-to-head comparison of the two acquisition (2D vs 3D) methods can give conclusive evidence of their accuracy in determination of ischemic burden.”

The sensitivity of both MPS and CMR were 94 percent, although each had benefits in specificity and accuracy, with 63 percent (MPS) vs. 81 percent (CMR) and 79 percent (MPS) vs. 88 percent (CMR), respectively.

Jogiya et al wrote, “Combined with CMR assessment of cardiac function and viability the technique holds promise as a complete non-invasive and radiation-free diagnostic and risk stratification tool for patients with known or suspected CAD.”

The paper was published online May 27 in Circulation: Cardiovascular Imaging.