131I-19-IODOCHOLESTEROL SCINTIGRAPHY OF THE ADRENAL CORTEX

Abstract

ABSTRACT 131I-19-iodocholesterol scintigraphy of the adrenal cortex has been carried out in 26 patients. In 4 patients with normal adrenocortical function the tracer was equally accumulated on the two sides. In 7 patients with untreated Cushing's syndrome, bilateral uptake was found in 4 patients with bilateral hyperplasia whereas unilateral visualization was obtained in three cases of cortisol producing adenomas. The side localization was confirmed at operation. Eight patients had been operated for Cushing's syndrome prior to the scintigraphy. Remnant adrenocortical tissue with negligible or subnormal function (4 patients) could not be visualized. Normo- or hyperfunctioning remnant tissue was visualized in 3 patients. One patient had recurrent hypercorticism due to metastases from a previously removed adrenocortical carcinoma; a single pelvic accumulation was seen, whereas several metastases in the abdomen and thorax were not visualized. Four patients with aldosteronism were investigated. Three had primary aldosteronism due to an adrenocortical adenoma. In two of these, the site of the adrenal lesion was localized pre-operatively. In the third patient, equal bilateral accumulation of iodocholesterol was seen even after suppression with dexamethasone. At operation a small tumour was found. In 1 patient with indeterminate aldosteronism both glands were visualized and at a second examination the uptake was equally suppressed by dexamethasone. Finally 3 patients were investigated. One had a testosterone producing tumour of the right ovary. The tumour was not visualized on the scintigram in spite of a slight accumulation of activity as measured in vitro. Another patient with a cyst of the right adrenal gland presented a defect in the activity on the affected side. In the third patient previously subjected to hypophysectomy, the adrenal cortex was visualized only after ACTH-stimulation. The 131I-19-iodocholesterol scintigraphy is a valuable method for the diagnosis and localization of cortisol and aldosterone producing tumours, and for the localization of normo- and hyperfunctioning adrenocortical remnants. The interpretation of the scintigrams must be based on relevant biochemical assays.