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Congenital pulmonary atresia: photographic subtraction as an aid in recognizing hypoplastic pulmonary arteries.

Photographic subtraction is a valuable adjunct for studying patients with pulmonary atresia, ventricular septal defect, and systemic pulmonary collateral vessels. In about 9% of 282 patients, it helped identify the true central pulmonary arteries and whether or not they were confluent. This technique, used retrospectively in evaluating patients previously considered inoperable, has permitted recall of several patients for repeat study and probable corrective or palliative surgery.