Functional assessment of the right ventricle with gated myocardial perfusion SPECT

The evaluation of right ventricular function can provide valuable information in a variety of cardiac and noncardiac conditions. Functional assessment of the right ventricle is difficult because of its anatomy and geometry. The authors describe a method for assessing right ventricular function using gated myocardial perfusion SPECT.

In 20 patients, right and left ventricular ejection fractions (RVEF, LVEF) were determined using gated blood-pool scintigraphy (GBPS) and gated myocardial perfusion SPECT (GSPECT). To avoid contamination with right atrial activity, the two-frame method was adopted for gated blood-pool data when RVEF was measured. In nine patients with normal right ventricles, an index of wall thickening for the right ventricle was derived from the peak systolic and diastolic counts in the free wall.

Linear correlation between the two methods adopted for calculation of LVEF and RVEF was good. Bland-Altman analysis revealed good agreement between the two methods with no specific bias. The mean LVEF was 47.9 +/- 12% (GBPS) and 47.3 +/- 12.4 (GSPECT). The mean RVEF was 43.2 +/- 9.6% (GBPS) and 44.2 +/- 8.5% (GSPECT). In both cases, the values were not significantly different. The mean wall motion index was 35%. There was no correlation between the wall thickness index and ejection fraction, but the index was greater in patients with a normal right ventricle compared with those with reduced RVEF.

Gated SPECT offers an alternative to GBPS for the functional assessment of the right ventricle. Using GSPECT will allow the simultaneous assessment of both the right and left ventricles.