Comparison between vertical parallel hole collimator and 30° rotating slant hole collimator for assessing global and regional left ventricular function by radionuclide angiography

Left ventricular ejection fraction (LVEF) and regional wall motion abnormalities were determined in 40 patients (30 with coronary artery disease and 10 with valvular heart disease) using equilibrium radionuclide angiography. Scintigraphic acquisitions were collected in random order with 2 different collimators as follows: in anterior face (AF), left anterior oblique (25°–45° LAO) and 70° LAO, with a vertical parallel hole collimator (VTC), and in 25°–45° LAO and 65°–80° LAO with a 30° rotating slant hole collimator (RSHC), with the slant of the collimator directed towards the cardiac apex in both projections. Results were compared to contrast ventriculography (CV) performed in the 30° right anterior view (3 segments: anterior, apical, inferior) and in a 60° left anterior oblique view (3 segments: septal, apical and lateral). Radionuclide LVEF in both series was closely correlated with contrast ventriculographic LVEF (r=0.89, VTC vs CV and r=0.87, RSHC vs CV, respectively). Regional wall motion analysis was only performed among the 30 patients suffering from coronary heart disease. Eight contrast angiographic studies were normal and 22 abnormal. Global sensitivity and specificity were 100% and 63% with the VTC (3 false positives) and 91% and 87% with the 30° RSHC (2 false negatives and 1 false positive, P=ns). Agreement for the localisation of the regional wall motion abnormalities between CV and radionuclide angiography was 70.6% with the VTC and 71.2% with the RSHC (P=ns). Intensity of the regional wall motion abnormalities was assessed with the 30° RSHC as well as with the VTC (r=0.7 score CV vs score VTC and r=0.8 score CV vs score RSHC, P=ns). We conclude that the use of a rotating slant hole collimator associated with radionuclide ventriculography allows reliable determination of left ventricular ejection fraction and accurate assessment of regional wall motion abnormalities with only two projections while the vertical collimator requires three.