In patients with definitive results of noninvasive biochemical tests for APA, and positive findings of unilateral, focal adrenal lesion on MRI or CT, unilateral adrenalectomy may be justified without further tedious and invasive examinations. CT should still be the first screening test; however, high-resolution MRI is a useful diagnostic supplement for patients with strong clinical evidence of APA and negative or equivocal findings on CT.