Accuracy of CT scanning and adrenal vein sampling in the pre-operative localization of aldosterone-secreting adrenal adenomas

Abstract

In primary hyperaldosteronism, it is important to distinguish between unilateral and bilateral disease, as management strategies differ. In the period 1983-95, we identified 34 patients with primary hyperaldosteronism. Following further investigations, a diagnosis of aldosterone-secreting adenoma was made in 17 patients, and surgery was performed. Computed tomography clearly localized an apparent adenoma (discrete adenoma=1 cm diameter; normal contralateral gland) in only 10 of these patients (59%); two of these 'adenomas' were subsequently shown to be hyperplastic glands without adenomas. Histological examination showed adrenal adenomas in the remaining 15 patients. An 'adenoma' also appeared to be clearly localized in 3/17 patients later classified as having bilateral adrenal hyperplasia by adrenal vein sampling. CT scanning, therefore clearly localizes adenomas in only 50% of histologically proven cases, and can also produce misleading results. Adrenal vein sampling results altered our management approach in one third of cases. On the basis of our detailed results we would recommend surgery if there is clear evidence of unilateral aldosterone secretion along with CT findings which may not be strictly localizing but are in keeping with the dominant side on adrenal vein sampling. The decision to refer for surgery in primary hyperaldosteronism can be difficult, and we would caution against too heavy a reliance on CT results when recommending adrenalectomy, and suggest that adrenal vein sampling should remain a routine part of the investigation of patients with primary hyperaldosteronism.

Adrenal venous sampling for stratifying patients for surgery of adrenal nodules detected using dynamic contrast enhanced CT

“…Previous studies determined the clinical impact of adrenalectomy chosen based on CT alone or CT plus AVS (5,14,(17)(18)(19). Those authors reported that the reduction in BP, number of hypertensive medications, plasma aldosterone, and potassium normalization at follow-up were equivalent in the two groups and concluded that CT could be used to diagnose nodules >10 mm reliably and that AVS should be used when CT is normal or both adrenal glands are abnormal (29,30).…”

“…However, before making this decision, an affected-to-unaffected aldosterone ratio >2.2 with an unaffected-to-inferior vena cava (IVC) ratio <1.7 were used to define lateralization (18). Concordance was defined as CT showing a normal gland contralateral to the aldosterone lateralization.…”

Diagnostic performance of CT versus MR in detecting aldosterone-producing adenoma in primary hyperaldosteronism (Conn?s syndrome)

“…Both CT and MR imaging have been used for the detection of aldosterone-producing adenoma. If the imaging results are equivocal, then adrenal venous sampling, an invasive and a technically difficult procedure, is indicated for further evaluation [2][3][4][5][6][7][8][9].…”

“…Several studies have examined the performance of CT in the detection of aldosterone-producing adenoma, with sensitivities and specificities varying from 53-100% and 33-100%, respectively [2][3][4][5][6][7][8][9][10] (Table 1). Recently, we reported a sensitivity of 70% and a specificity of 100%, respectively, for MR imaging in the detection of aldosterone-producing adenoma in primary hyperaldosteronism [11].…”

Adrenal Venous Sampling Is Absolutely Requisite for Definitively Diagnosing Primary Aldosteronism as Well as for Detecting Laterality of the Adrenal Lesion

“…In the diagnosis of PA, localization should be accurately evaluated in order to select appropriate therapeutic strategies, such as unilateral adrenalectomy and drug treatment. AVS is essential to establish the correct diagnosis of PA (18)(19)(20)(21).…”