Comparison between MR imaging and Tc-99m MIBI scintigraphy in the evaluation of recurrent or persistent hyperparathyroidism

PURPOSE: Po compare the sensitivity and positive predictive value of magnet ic resonance (MR) imaging and technetium 99m 2-methoxyisobutyl-isonitrile ( MIBI) scintigraphy for the detection of hyperfunctioning parathyroid tissue when used alone and in combination in a large patient population with recu rrent or persistent hyperparathyroidism (HPT). MATERIALS AND METHODS: In 98 consecutive patients with biochemically proved recurrent or persistent HPT after surgery, MR imaging and Tc-99m MIBI study findings wer e retrospectively reviewed and compared with surgical and histopathologic f indings. The sensitivity and positive predictive value of MR imaging and Tc -99m MIBI scintigraphy were compared with each other and in combination. RESULTS: In these patients, 130 abnormal parathyroid glands were identified at surgery. The sensitivity and positive predictive value of MR imaging we re 82% (95% CI: 75%, 89%) and 89%, respectively; those for Tc-99m MIBI scin tigraphy were 85% (95% CI: 79%, 91%) and 89%. No significant difference was found between MR imaging and Tc-99m MIBI scintigraphy for sensitivity (P = .7). The sensitivity and positive predictive value for the detection of abn ormal parathyroid tissue on a per-gland basis increased to 94% (95% CI: 90% , 98%) and 98%, respectively, when only one of the two tests was required t o be positive. CONCLUSION: MR imaging and Tc-99m MIBI scintigraphy have similarly good sen sitivity and positive predictive value for the detection of hyperfunctionin g parathyroid tissue in patients after surgery. The combination of the two tests provided a substantial increase in sensitivity and positive predictiv e value.