Detection and Characterization of Parathyroid Adenoma/Hyperplasia for Preoperative Localization: Comparison Between 11C-Methionine PET/CT and 99mTc-Sestamibi Scintigraphy

Abstract

Purpose 11 C-Methionine PET/CT (Met-PET/CT) is a useful imaging method for detection of parathyroid adenoma; however, the reported detection rate has been variable. The current study was intended to investigate detection sensitivity and preoperative localization of parathyroid adenoma (PA) or parathyroid hyperplasia (PH) on Met-PET/CT compared with Tc-sestamibi (MIBI) scintigraphy in patients with primary hyperparathyroidism (HPT) or suspected PA. Methods Met-PET/CT and MIBI scintigraphy images were reviewed by two nuclear medicine physicians unaware of pathologic results. Detection sensitivities and preoperative localization of detected parathyroid tissues into five predefined segments were evaluated by visual assessment and semiquantitative analysis with ratio of standardized uptake values (SUVR) between parathyroid tissue and normal lung as reference. Linear regression analysis with SUVR and serum parathyroid hormone (sPTH) was performed for characterization of PA or PH. Predicted PTH (pPTH) was calculated and compared with sPTH in PH and PA. Each pPTH was obtained for a calculated SUVR by using linear regression model from the result of previous linear regression analysis between SUVR and sPTH. Results In 16 patients, detection sensitivities of Met-PET/CT and MIBI scintigraphy were 91.7 % (11/12) and 41.7 % (5/12) for PA and PH including both biopsy-confirmed and clinicallysuspected cases, and 100 % (8/8) and 50 % (4/8) for pathologically confirmed PA and PH cases only, respectively. Met-PET/CT showed higher performance than MIBI scintigraphy in localization of parathyroid tissues; correct localization rate was 87.5 % (7/8) on Met-PET/CT and 50 % (4/8) on MIBI scintigraphy. In semi-quantitative analysis, SUVR was linearly associated with sPTH by linear regression analysis (sPTH=39.53×SUVR−89.84, p=0.0383). There was a borderline significant difference in pPTH between PH and PA (35.1 vs 204.7±164.0, p=0.052), while there was no significant difference in sPTH between PH and PA (289 vs 230.4±160.4, p=0.305). Conclusions Met-PET/CT has a potential to be a useful diagnostic modality for preoperative detection and localization of parathyroid tissues with higher sensitivity than MIBI scintigraphy, and for characterization of PA or PH.

Five-year retrospective study on primary hyperparathyroidism in South India: Emerging roles of minimally invasive parathyroidectomy and preoperative localization with methionine positron emission tomography-computed tomography scan

“…Some studies have reported better sensitivity and specificity (91%–100%) for 99m Tc sestamibi scan. [ 29 30 ] In an Indian study, the sensitivity and positive predictive value of USG were 73% and 95%, respectively. The sensitivity and positive predictive value were 98% for 99m Tc sestamibi scintigraphy.…”

Localization of parathyroid adenomas using 11C-methionine pet after prior inconclusive imaging

“…In a recent smaller study with 18 patients, Braeuning et al found a sensitivity per patient of 91.7% and a sensitivity per lesion of 73.3% after a prior negative 99m Tc-MIBI-SPECT/CT [ 24 ]. Another smaller study by Chun et al who included 16 patients found a sensitivity of 91.7%, but did not select patients with prior negative imaging [ 20 ]. Traub-Weidinger et al included 15 patients with negative 99m Tc-MIBI SPECT/CT and earlier neck surgery because of pHPT and/or thyroid disorder and found a sensitivity of 40% [ 25 ].…”

“…C-methionine accumulates in the parathyroid adenoma and is involved in the synthesis of the precursor of PTH [ 17 – 19 ]. It improves the detection performance of parathyroid tissue due to a better spatial resolution of PET/CT [ 20 ]. When 11 C-MET PET/CT became available in 2006 at our institute, we used this nuclear imaging modality as a step up approach after inconclusive imaging.…”

Parathyroid adenoma upstaging the lung cancer

“…In different series 44-90 % of parathyroid adenomas take up FDG at variable degrees relating to the mitotic activity [7][8][9]. The 10-15 % of parathyroid adenomas are ectopic [4].…”