Performance of F-18 Fluorocholine PET/CT for Detection of Hyperfunctioning Parathyroid Tissue in Patients with Elevated Parathyroid Hormone Levels and Negative or Discrepant Results in conventional Imaging

Abstract

Objective: Our aim was to assess the diagnostic performance of F-18 fluorocholine (FCH) positron emission tomography/ computed tomography (PET/CT) in detecting hyperfunctioning parathyroid tissue (HPT) in patients with elevated parathyroid hormone levels with negative or inconclusive conventional imaging results and to compare the findings with those obtained using technetium-99m sestamibi (MIBI) scintigraphy and neck ultrasonography (US). Materials and Methods: Images of 105 patients with hyperparathyroidism who underwent FCH PET/CT, dual-phase MIBI parathyroid scintigraphy (median interval: 42 days), and neck US were retrospectively analyzed. The gold standard was histopathological findings for 81 patients who underwent parathyroidectomy and clinical follow-up findings in the remaining 24 patients. Sensitivities, positive predictive values (PPVs), and accuracies were calculated for all imaging modalities. Results: Among the 81 patients who underwent parathyroidectomy, either parathyroid adenoma (n = 64), hyperplasia (n = 9), neoplasia (n = 4), or both parathyroid adenoma and hyperplasia (n = 1) were detected, except 3 patients who did not show HPT. Of the 24 (23%) patients who were followed-up without operation, 22 (92%) showed persistent hyperparathyroidism. FCH PET/CT showed significantly higher sensitivity than MIBI scintigraphy and US in detection of HPT (p < 0.01). Sensitivity, PPV, and accuracy of FCH PET/CT were 94.1% (95/101), 97.9% (95/97), and 92.4% (97/105), respectively. The corresponding values for MIBI scintigraphy and US were 45.1% (46/102), 97.9% (46/47), and 45.7% (48/105) and 44.1% (45/102), 93.8% (45/48), and 42.9% (45/105), respectively. Among the 35 patients showing negative MIBI scintigraphy and neck US findings, 30 (86%) showed positive results on FCH PET/CT. FCH PET/CT could demonstrate ectopic locations of HPT in 11 patients whereas MIBI and US showed positive findings in only 6 and 3 patients, respectively. Conclusion: FCH PET/CT is an effective imaging modality for detection of HPT with the highest sensitivity among the available imaging techniques. Therefore, FCH PET/CT can be recommended especially for patients who show negative or inconclusive results on conventional imaging.

Diagnostic Value of Choline PET in the Preoperative Localization of Hyperfunctioning Parathyroid Gland(s): A Comprehensive Overview

“…In the two studies performed by the same group, a heterogeneous population of patients suffering from both primary and secondary HPT was considered, reaching a lesion-based sensitivity of 89% but a detection rate on a per patient level of 92% [17]. More recently, Uslu-Beşli et al confirmed the superiority of choline PET when compared with inconclusive traditional imaging methods [41]. Michaud et al were one of the first to investigate the role of [ 18 F]FCH PET/CT in HPT as second line imaging.…”

Misleading localization by 18F-fluorocholine PET/CT in familial hypocalciuric hypercalcemia type-3: a case report

“…FCH PET/CT has been increasingly gaining acceptance as the best imaging modality [ 15 – 25 ]. Compared to conventional functional imaging, FCH-PET/CT does not only have superior sensitivity, but also better spatial resolution, lower radiation exposure, and shorter study time [ 15 , 20 , 21 ].…”

“…A recent systematic review (23 articles, 1112 patients) compared FCH-PET/CT with conventional morphological and functional imaging in patients with biochemical hyperparathyroidism and found that FCH-PET/CT sensitivity ranged from 58 %-100 % which may be related to type of conventional imaging, patient population, and FCH-PET/CT protocol [ 18 ]. More recent studies found FCH-PET/CT sensitivity of 91 % (84/92 lesions) when defining lesions with both positive and inconclusive FCH uptakes as positive [ 19 ], 94 % in 101 patients with PTH-dependent hypercalcemia and negative or discordant conventional imaging (vs. 45 % and 44 % for MIBI scan and US, respectively) [ 20 ], 92 % in 103 patients (vs. 39–56 % for conventional scintigraphy) [ 21 ], and 62 % 47 patients after inconclusive first line imaging including US and subtraction scan [ 22 ]. Previous meta-analyses showed pooled sensitivity of 90 % (8 studies, 272 patients) [ 15 ] and of 95 % on per-patient analysis and 92 % on per-lesion analysis ( 14 studies, 517 patients) [ 16 ].…”

“…Nevertheless, sensitivity of FCH-PET/CT for multiple functioning parathyroid gland is less well documented and appears to be lower, which may be due to smaller size and lighter weight in multiple functioning glands. It was 78 % in 9 patients [ 20 ], and 88 % in 14 patients (4 with 2 adenomas and 10 with 31 hyperplastic glands) [ 21 ].…”

“…The 2018 meta-analysis by Kim et al showed a pooled specificity of 94 % [ 15 ] and in the recent systematic review by Evangelista et al, specificity ranged from 12.5 % (per lesion) to 100 % [ 18 ]. More recent studies showed a false positive rate of 8.7 % in 84 patients when defining lesions with both positive and inconclusive uptake as positive [ 19 ], 1 % in 103 patients [ 21 ], and 2 % in 105 patients [ 20 ]. Several causes of false positive FCH-PET/CT uptake have been reported, including ganglioneuroma and thyroid remnants, [ 31 ] well differentiated thyroid cancer and inflammatory lymph nodes [ 20 ], histologically classified thyroid tissue [ 21 ], thyroid nodules and normal reactive or metastatic lymph nodes [ 16 ], thyroid gland uptake [ 24 ], and thymoma in patient with familial primary hyperparathyroidism [ 32 ].…”