Difficulties in the prospective diagnosis of functional adrenal diseases by CT

The accuracy of prospective diagnosis of functional adrenal disorders by computed tomography (CT) was evaluated in 65 patients strongly suspected of having such disorders. Thirty-seven patients also underwent adrenal venography and selective adrenal venous sampling. Of the 65 patients, 21 had a hyperfunctioning cortical adenoma, 25 had cortical or medullary hyperplasia, and 11 pheochromocytoma, while 10 had no functional adrenal disease. Diagnosis by CT alone was correct in 66%; diagnosis by CT and venous sampling was correct in 89%. Incorrect prospective CT diagnosis resulted most often from a normal appearance of functionally hyperplastic glands (9 cases), nodular hyperplasia simulating a focal adenoma (8 cases), or an incidental nonfunctioning mass (3 cases). This study emphasizes the need to correlate CT findings with biochemical evaluation and the usefulness of venous sampling in selected cases to avoid inappropriate surgery. When CT is interpreted in correlation with complete biochemical analysis, correct diagnosis can usually be made. A small number of cases may still require adrenal venous sampling.