Usefulness of the combination of ultrasonography and 99mTc-sestamibi scintigraphy in the preoperative evaluation of uremic secondary hyperparathyroidism.

Abstract

The usefulness of the combination of technetium-99m-methoxyisobutylisonitrile (99mTc-MIBI) parathyroid scintigraphy and ultrasonography to detect parathyroid glands (PTGs) in secondary hyperparathyroidism (SHPT) is still controversial. In all, 21 patients with SHPT underwent parathyroidectomy. The sensitivity and specificity of ultrasonography and scintigraphy related to site, size, hyperplasia type of PTG, concomitant thyroid disease, and the frequency of intraoperative frozen sections were determined. The sensitivities of scintigraphy and ultrasonography were 62% and 55%, and the specificity was 95% for both procedures. The sensitivity of combined techniques was 73%. The scintigraphy detected 7/9 (78%) ectopic PTGs, whereas ultrasonography was always negative. A PTG maximum longitudinal diameter <8 mm, the presence of diffuse hyperplasia, the upper localization of glands, and the presence of concomitant thyroid disease reduced the sensitivity and specificity of imaging techniques. In cases of positive imaging, the rate of intraoperative frozen sections was significantly lower. The ultrasonography and sestamibi scintigraphy, which showed a higher sensitivity than that of either ultrasonography or scintigraphy alone, led to a reduction of intraoperative frozen sections and to preoperative diagnosis of ectopic (29%) or supernumerary PTGs (10%) and concomitant nodular thyroid disease (24%).