[Diagnosis of Conn's adenoma. Comparative study of x-ray computed tomography and scintigraphy using 19-noriodocholesterol].

OBJECTIVE

In order to differentiate an aldosterone producing adenoma (APA) and a bilateral adrenal hyperplasia (BAH) in case of primary hyperaldosteronism, an adrenal CT-scan is usually used as first line exploration. The contribution of adrenal 19-noriodocholesterol (NP59)-scintigraphy is controversial.

PATIENTS AND METHODS

We describe 17 cases of primary hyperaldosteronism referred to surgery for suspected APA. The value of abdominal CT-scan and of adrenal scintigraphy was studied.

RESULTS

After unilateral adrenalectomy, 15 cases with confirmed APA were cured and 2 cases with an unilateral hyperplastic macro nodule showed persistence of the disease. The pathologic findings were concordant with CT-scan in 76% (13/17) and with scintigraphy in 88% (15/17). Similar sensitivity was found for CT-scan and scintigraphy (86% and 88%) with 2 false negative results with both techniques. False positive results were observed only with CT-scan (2 cases) suggesting that scintigraphy has a better specificity. No case was misdiagnosed by both techniques.

CONCLUSION

These results suggest that NP59-scintigraphy is complementary to adrenal CT-scan for the recognition of APA and is particularly useful in case of a unilateral hyperplastic macro nodule mimicking an APA.