Preoperative contrast-enhanced MRI of the parathyroid glands in hyperparathyroidism

RATIONALE AND OBJECTIVES. TO evaluate the sensitivity of contrast-enhanced MRI in the preoperative detection of abnormal parathyroid glands in patients with clinical evidence of hyperparathyroidism. METHODS. Twenty-eight patients with biochemical evidence of hyperparathyroidism underwent contrast-enhanced preoperative MRI of the parathyroid glands. Two blinded readers assessed the MR images by consensus, and MR results were subsequently correlated with those from surgery (location, diameter, weight) and histopathology. RESULTS. MRI depicted 32 of 39 surgically proved abnormal parathyroid glands (sensitivity 82%; 95% confidence interval, 66%-92%), and 1 of 114 (0.9%) was incorrectly considered abnormal. All ectopic glands were correctly identified (2 mediastinal, 1 submandibular). Sensitivity was superior for adenomas but less for hyperplasia (adenomas 87%; 95% confidence interval, 67%-97%; hyperplasia 75%; 95% confidence interval, 47%-92%), Among all lesions, atypical signal characteristics on MRI were observed in 34% of lesions (9% hyperintense signals on T2- and T1-weighted images; 25% isointense signals on T2- and T1-weighted images), with improved lesion detection after contrast administration in 17% of lesions. CONCLUSIONS. MRI of the parathyroid glands presented a sensitive imaging modality, thus demonstrating its high potential to preoperatively detect abnormal glands. Moreover, in a minor proportion of patients with atypical parathyroid lesion characteristics, contrast administration may increase lesion detectability.