Assessment of right ventricular volumes by magnetic resonance imaging and by radionuclide angiography

Right ventricular volumes including right ventricular ejection fraction (RVEF) were determined in 11 patients with ischemic heart disease by oblique multislice MRI and by first-pass radionuclide angiography (RNA) using separate (FPSA) as well as fixed (FPFA) systolic and diastolic areas of interest. RNA and MRI were performed on the same day. Before MRI, arterial and venous catheters were inserted for measuring cardiac output (CO) by the indicator dilution principle; CO was thus measured simultaneously with the MRI as well as with the RNA procedures. Basal hemodynamics were unchanged between the two studies with indicator dilution CO of 5.5 + 1.0 and 5.5 + 1.2 liters/min (mean + SD) and heart rate of twice 63 + 10 beats/min during MRI and RNA. There was a close correlation between values of RVEF determined by MRI and by FPSA (r = 0.86), whereas there was no correlation between RVEF determined by MRI and FPFA (r = 0.37). Right ventricular volumes determined by MRI correlated with volumes determined by FPSA-RVEF and indicator dilution CO (r = 0.81 for right ventricular end-diastolic volume and r = 0.85 for right ventricular end-systolic volume). The absolute volumes, however, showed wide limits of agreement.