11C-Metomidate PET-CT versus adrenal vein sampling to subtype primary aldosteronism: a prospective clinical trial

Abstract

u,v , for the PA CURE investigators à Objective: Adrenal vein sampling (AVS) is recommended to subtype primary aldosteronism, but it is technically challenging. We compared 11 C-Metomidate-PET-computed tomography (PET-CT) and AVS for subtyping of primary aldosteronism.Methods: Patients with confirmed primary aldosteronism underwent both AVS and 11 C-Metomidate PET-CT (postdexamethasone). All results were reviewed at a multidisciplinary meeting to decide on final subtype diagnosis. Primary outcome was accuracy of PET versus AVS to diagnosis of unilateral primary aldosteronism based on post-surgical biochemical cure. Secondary outcome was accuracy of both tests to final subtype diagnosis.Results: All 25 patients recruited underwent PET and successful AVS (100%). Final diagnosis was unilateral in 22 patients, bilateral in two and indeterminate in one due to discordant lateralization. Twenty patients with unilateral primary aldosteronism underwent surgery, with 100% complete biochemical success, and 75% complete/partial clinical success. For the primary outcome, sensitivity of PET was 80% [95% confidence interval (95% CI): 56.3-94.3] and AVS was 75% (95% CI: 50.9-91.3). For the secondary outcome, sensitivity and specificity of PET was 81.9% (95% CI: 59.7-94.8) and 100% (95% CI: 15.8-100), and AVS was 68.2% (95% CI: 45.1-86.1) and 100% (95% CI: 15.8-100), respectively. Twelve out of 20 (60%) patients had both PET and AVS lateralization, four (20%) PET-only, three (15%) AVS-only, while one patient did not lateralize on PET or AVS. Post-surgery outcomes did not differ between patients identified by either test. Conclusion:In our pilot study, 11 C-Metomidate PET-CT performed comparably to AVS, and this should be validated in larger studies. PET identified patients with unilateral primary aldosteronism missed on AVS, and these tests could be used together to identify more patients with unilateral primary aldosteronism.

Lateralization in 11C‐Metomidate PET and outcome of adrenalectomy in primary aldosteronism

“…However, the ability of 11 C‐MTO‐PET to diagnose unilateral non‐classic forms of PA that are becoming more prevalent remains unanswered by these studies. Altogether, differences in patient selection may partly explain the discrepancies between our results and those by Puar et al 31 …”

“…[27][28][29][30] Despite great expectations, the use of 11 17 However, the ability of 11 C-MTO-PET to diagnose unilateral non-classic forms of PA that are becoming more prevalent remains unanswered by these studies. Altogether, differences in patient selection may partly explain the discrepancies between our results and those by Puar et al 31 A limitation of the current study is that contrary to the protocol developed by Burton et al, 17 our PET protocol did not include pretreatment with dexamethasone. Therefore, background CYP11B1 activity, that is tracer uptake by cortisol synthase, may decrease the SUV differences in the PET scan.…”

“…Burton et al 17 performed PET studies on selected patients based on anatomical findings, and the study by O'Shea et al 18 presented a retrospective case series with only one patient undergoing both AVS and 11 C‐MTO‐PET preoperatively. In a recent prospective study with 20 out of 25 subjects undergoing adrenalectomy, 11 C‐MTO‐PET performed comparably to AVS and even identified unilateral PA cases missed by AVS 31 . Besides the small number of subjects included, it must be noted that up to 76% of the study subjects presented with a unilateral adenoma in CT and 90% of adrenalectomized patients showed classic unilateral PA in histopathology.…”

Clinical significance of CYP11B2 immunostaining in unilateral primary aldosteronism

“…Our results are consistent with the meta-analysis of Yan et al ( 33 ) on the superiority of AVS compared to CT/MRI. In line with recent prospective trials ( 34 , 35 ), those who underwent a 11 C-MTO-PET-guided operation achieved comparable biochemical cure as AVS-guided operation but the small numbers of subjects must be considered in our subgroup analyses. As expected, adrenal scintigraphy detected only large APAs, and this method has been abandoned due to its low sensitivity in PA subtyping ( 17 ).…”

Primary Aldosteronism and Drug Resistant Hypertension: A “Chicken-Egg” Story

“…AVS is technically demanding, not feasible for all patients, and not available at all centers. For these reasons, attempts were made to overcome this procedure, such as using PET-CT [60][61][62][63][64][65][66][67][68][69] or only CT-based management. The Spartacus randomized clinical trial claimed equivalence of CT and AVS-based strategy [70].…”