Imaging for adrenal tumours.

Modern medical imaging has transformed the diagnosis and management of adrenal disease. The various types of adrenal tumours bear different aspects of problems in diagnostic imaging. The investigation used must be determined and monitored individually, as directed by the clinical and biochemical findings. CT plays a central role in the localization of the functioning adrenal tumours. It is regarded as the imaging modality of choice because it combines safety with a high rate of detection. It is highly sensitive in the localization of the large adrenal tumours that account for Cushing's syndrome and phaeochromocytomas, as well as the small tumours that account for primary hyperaldosteronism. It is, however, not reliable for the detection of adrenal hyperplasia, and does not yield functional imaging information. For small tumours not detectable by CT, and for ectopic tumours, complementary investigations with appropriate application of venous sampling, radionuclide scintigraphy and occasionally arteriography, will be very useful. CT-guided percutaneous biopsy is employed for the incidentalomas in oncologic patients. MRI appears to hold a great potential for the diagnosis of adrenal disorders, but this modality is awaiting wider availability of instrumentation and clearer documentation of techniques.