THE COMPLEMENTARY ROLES OF FAST SPIN-ECHO MR-IMAGING AND DOUBLE-PHASETC-99M-SESTAMIBI SCINTIGRAPHY FOR LOCALIZATION OF HYPERFUNCTIONING PARATHYROID-GLANDS

OBJECTIVE. Our purpose was to evaluate and compare prospectively fast spin-echo MR imaging and double-phase technetium-99m-sestamibi scintig raphy for preoperative localization of hyperfunctioning parathyroid gl ands in high-risk surgical patients. SUBJECTS AND METHODS. Twenty-five patients, including 17 with a history of neck surgery, underwent preo perative MR imaging and technetium-99m-sestamibi scintigraphy. Initial interpretation of each study was made independently by two radiologis ts and then done in combination. At surgery, the location, weight, and dimensions, as well as detailed histopathologic evaluations, of all e xcised glands were recorded. RESULTS. All but two patients became norm ocalcemic after surgery. MR and sestamibi imaging revealed 31 of 37 (8 4%) and 29 of 37 (79%) of all abnormal glands, respectively. Sensitivi ties of MR and sestamibi imaging were higher for adenomas (17 of 18 [9 4%] and 16 of 18 [89%], respectively) than for hyperplastic glands (14 of 19 [74%] and 13 of 19 [68%], respectively). The specificity of ses tamibi imaging (94%) exceeded that of MR imaging (75%). All ectopic gl ands (n = 8) were correctly localized by both techniques. Glands with atypical MR imaging characteristics (isointense or hyperintense to nor mal thyroid on T1-weighted spin-echo and fast spin-echo images) were m ore likely to have increased fat, chronic hemorrhage, or sclerosis and fibrosis (p < .05). When MR imaging and sestamibi studies were interp reted together, their sensitivities for adenomas and for hyperplastic glands were 94% (17 of 18) and 84% (16 of 19), respectively. Overall s ensitivity of MR imaging and sestamibi studies interpreted together wa s 89%; overall specificity was 95%. CONCLUSION. The greater specificit y and anatomic coverage of sestamibi scintigraphy coupled with the gre ater anatomic detail provided by MR imaging and its improved sensitivi ty over sestamibi imaging in specific patients may justify using both techniques in high-risk surgical patients who have hyperparathyroidism , particularly patients undergoing repeat surgery.