Accuracy of preoperative diagnosis for primary hyperparathyroidism by CT, US and scintigraphy

We determined the usefulness of computed tomography (CT), ultrasonography (US) and Tc-Tl subtraction scintigraphy for preoperative diagnosis in 12 patients with primary hyperparathyroidism, all of which were solitary adenoma. Seven (63.6%) of 11 tumors were detected by CT, 7 (58.3%) of 12 tumors were detected by US, and 7 (63.6%) of 11 tumors were detected by Tc-Tl subtraction scintigraphy. Of 7 tumors with size>10 mm, 6 (85.7%) were detected by CT, 5 (71.4%) were detected by US, and 6 (85.7%) were detected by Tc-Tl subtraction scintigraphy, whereas only 1 (25%) with a diameter of 10 mm was detected by each of CT or Tc-Tl subtraction scintigraphy and 2 (40%) with diameters 10 mm were detected by US. Of 6 tumors situated behind the thyroid gland or intra thyroid gland, 5 (83.3%) were detected by CT and all 6 (100%) were detected by US, Tl-Tc subtraction scintigraphy, which was employed for 5 tumors, detected all 5 (100%). However, in the tumors situated beneath the thyroid gland only 2 (40%) of 5, 1 (16.7%) of 6 and 2 (33.3%) of 6 were detected by CT, US and Tc-Tl subtraction scintigraphy respectively. In 5 tumors without thyroid disease, 4 (80%) of 5 were detected by both CT and US, 3 (75%) of 4 were detected by Tc-Tl subtraction scintigraphy. However, in 7 tumors with thyroid diseases (papillary carcinoma, follicular carcinoma, follicular adenoma, chronic thyroiditis, and adenomatous goiter), 3 (50%) of 6 were detected by CT, 3 (42.9%) of 7 were detected by US and 4 (57.1%) of 7 were detected by Tc-Tl subtraction scintigraphy. Location of tumor was the factor most likely to make appropriate diagnosis difficult for primary hyperparathyroidism by any assessment method. (author)