Diagnostic value of adrenal iodine-131 6-beta-iodomethyl-19-norcholesterol scintigraphy for primary aldosteronism

Abstract

Background Primary aldosteronism (PA) is a common cause of secondary hypertension. Among the many leading causes of PA, the two most frequent are, bilateral adrenal hyperplasia (BAH) and aldosterone-producing adenomas (APA). Since a solitary APA may be cured surgically, but BAH needs lifelong pharmacologic therapy, confirmation is mandatory before surgery. We herein sought to determine the diagnostic value of iodine-131 6-beta-iodomethyl-19-norcholesterol (NP-59) adrenal scintigraphy to distinguish BAH from APA. Patients and methods Patients clinically suspected of PA from March 2000 to October 2016 were retrospectively analyzed. A total of 145 patients, including 74 postunilateral adrenalectomy and seven postradiofrequency ablation for adrenal mass, were reviewed. All patients received NP-59 adrenal scintigraphy prior to surgery. The accuracy of the NP-59 adrenal scintigraphy was confirmed by the pathologic findings and postoperative outcomes. Results Among 81 patients receiving interventional procedures for adrenal mass, adenoma was eventually diagnosed in 72 patients according to their pathologic results, with 60 unilaterally and seven bilaterally localized lesions by NP-59 scintigraphy; nevertheless, there were five negative findings initially. The sensitivity, specificity, and positive predictive value of NP-59 scintigraphy for APA detection were therefore 83.3, 44.4, and 92.3%, respectively. Moreover, single-photon emission computed tomography/computed tomography scan increased the sensitivity and specificity, but not the positive predictive value (85.0, 60.0, and 89.5%) of NP-59 scintigraphy in this study. Conclusion NP-59 adrenal scintigraphy is a useful imaging test to detect APA. Lateralization by this modality prior to surgical intervention may reduce the need for such invasive procedures as adrenal venous sampling.

Feasibility of Iodine-131 6β-Methyl-Iodo-19 Norcholesterol (NP-59) Scintigraphy to Complement Adrenal Venous Sampling in Management of Primary Aldosteronism: A Case Series

“…Simultaneous use of SPECT-CT with NP-59 scintigraphy improved the accuracy of NP-59 scintigraphy. 25 Moreover, Chen et al 26 demonstrated that NP-59 scintigraphy with SPECT/CT had a role in early diagnosis for subclinical or atypical feature of PA or PA combined chronic kidney disease. In fact, NP-59 scintigraphy was suggested in inconclusive cases of AVS and in prediction of the existence of subclinical Cushing syndrome in adrenal incidentaloma.…”

Adrenal Incidentaloma

“…The emergence of integrated single-photon emission computed tomography-computed tomography (SPECT-CT) systems has led to a resurgence of interest in the use of NP-59 scintigraphy ( 358 ). Recent data have reported a positive predictive value of 92% for differentiation of aldosterone-producing adenoma from bilateral adrenal hyperplasia in primary aldosteronism, potentially reducing the need for invasive adrenal venous sampling ( 359 ). Limitations of NP-59 scintigraphy including the requirement for prolonged dexamethasone suppression, the need for sequential imaging over several days, and relatively high radiation dose, have stimulated the development of other functional imaging techniques in the diagnosis of primary aldosteronism ( 360 ).…”

Elevated 131I-MIBG activity in adrenocortical adenoma—what other imaging options do we have?

“…In addition, 11 C-metomidate has been suggested as a tracer to distinguish cortical and non-cortical adrenal lesions and is used to evaluate incidental adrenal masses (24,25). Furthermore, 131 I-6-betaiodomethyl-19-norcholesterol (NP-59) can accumulate in the adrenal cortex and has been reported to have high specificity and accuracy for identification of adrenocortical lesions, especially primary aldosteronism (PA) (26). NP-59 SPECT/CT is safe.…”