18F-fluorocholine PET/CT and conventional imaging in primary hyperparathyroidism

The purpose of this study was to assess the diagnostic capabilities of preoperative conventional imaging (^99mTc-MIBI scintigraphy, cervical ultrasonography [CUS]) and ¹⁸F-fluorocholine PET/CT (FCH PET/CT) in the detection of hyperfunctioning parathyroid gland in patients with primary hyperparathyroidism (PHPT) used alone or as a single imaging set.

A total of 51 consecutive patients (6 men, 45 women; mean age, 62 ± 11.6 [SD] years; age range: 28-86 years) with biochemically confirmed PHPT who underwent CUS, single-tracer dual phase ^99mTc-MIBI scintigraphy and FCH PET/CT were retrospectively included. ^99mTc-MIBI scintigraphy were performed immediately after CUS and interpreted by the same operators. FCH PET/CT examinations were interpreted independently by two nuclear medicine physicians. An additional reading session integrating the three imaging modalities read in consensus as a combined imaging set was performed.

At surgery, 74 lesions were removed (32 parathyroid adenomas, 38 parathyroid hyperplasia and 4 subnormal glands). Thirty-six patients (71%) had single-gland disease and 15 patients (29%) had multiglandular disease at histopathological analysis. On a patient basis, sensitivity and accuracy of FCH PET/CT, CUS and ^99mTc-MIBI scintigraphy for the detection of abnormal parathyroid glands were 76% (95% CI: 63-87%) and 76% (95% CI: 63-87%), 71% (95% CI: 56-83%) and 71% (95% CI: 56-83%), 33% (95% CI: 21-48%) and 33% (95% CI: 21-48%), respectively. The sensitivity of the combined imaging set was 94% (95% CI: 84-99%) and greater than the sensitivity of each individual imaging technique (P ≤ 0.001 for all).

Our results suggest that CUS, ^99mTc-MIBI scintigraphy and FCH PET/CT interpreted as a single imaging set could be the ideal practice to precisely localize parathyroid lesion in patients with PHPT before surgery.