Simultaneous biplane first-pass radionuclide angiocardiography using a scintillation camera with two perpendicular detectors

Generally performed in a single anterior or right anterior oblique (RAO) view, first-pass radionuclide angiocardiography (RNA) is limited due to its inability to evaluate septal and posterior wall motion. Methods: Thirty-five patients undergoing stress/rest sestamibi SPECT (22 mCi/22 mCi 2-day protocol) underwent biplane RNA at the time of resting injection. The stress SPECT images (acquired with the patient at rest) were ECG-gated to evaluate resting regional myocardial wall thickening. By this means wall motion assessed by RNA was compared to the presence of a resting SPECT perfusion defect accompanied by a localized decrease in wall thickening. Results: In 16 patients in whom both resting perfusion and wall thickening were normal, one demonstrated apical hypokinesis by RNA in the RAO view. In the other 29 patients, a total of 58 resting segmental perfusion defects with abnormal wall thickening were present (12 anterior, 13 inferior, 14 apical, 11 septal and 8 posterolateral). Wall motion abnormalities were detected in all these patients and in 57/58 segments (98%) by biplane RNA. Septal and posterolateral wall motion abnormalities were detected in only the LAO RNA study. In three patients, wall motion abnormalities were detected by LAO imaging only. Of the remaining 87 normally perfused segments in these 29 patients, RNA wall motion was normal in 85. Two posterolateral segments demonstrated apparent hypokinesis, probably due to left atrial overlap in the LAO projection. Conclusion: Simultaneous biplane RNA accurately detects wall motion abnormalities frequently missed by single-plane RAO imaging.