Lung perfusion scintigraphy in patients with congenital heart disease: sensitivity and important pitfalls.

The lung perfusion scans requested over a 5-year period for children with known congenital heart disease were reviewed retrospectively. Altogether, 102 lung perfusion scans were performed and comparable pulmonary arteriograms were available in 63 cases. There was agreement between scintigraphy and angiography in 50 (79%) cases and discrepancy in 13 (21%) cases. Scintigraphy was more sensitive in detecting small perfusion defects, particularly those seen only on oblique views. Pulmonary arteriography was more specific in identifying the cause of the perfusion abnormalities. The two techniques yield complementary information about lung perfusion. Perfusion scintigraphy is safe in children with congenital heart disease even with known pulmonary to systemic shunting. Many pitfalls could be avoided by careful choice of injection site, by knowledge of previous surgery and comparison with relevant angiograms.