Tc-99m sestamibi accuracy in detecting parathyroid tissue is increased when combined with preoperative laboratory values: a retrospective study in 453 Greek patients with chronic renal failure who underwent parathyroidectomy.

Purpose: Technetium(99m) sestamibi (MIBI) has poor sensitivity and specificity when applied to patients with secondary hyperparathyroidism. We investigated whether the combination of MIBI with preoperative parameters increased its accuracy.

Patients And Methods: This prospective study of 453 consecutive patients with secondary hyperparathyroidism who underwent parathyroidectomy (bilateral neck exploration) included preoperative MIBI scintigraphy compared with intraoperative and histopathology findings. Four patient groups were comprised according to the results: true positivity (TP), true negativity (TN), false positivity (FP), and false negativity (FN).

Results: MIBI scintigraphy sensitivity, specificity, positive predictive value, and negative predictive value were 66.4%, 50%, 76.3%, and 37.9%, respectively. For the TP group, mean age and mean parathormone (PTH) value were 56 years and 754, respectively. The binary logistic regression for the prediction (1) or not (2) of TP was as follows: 0.138 + (-.011) * age + 0.001 * PTH (P = .012). For the TN group, the mean age and mean phosphate value were 49 years and 5.24, respectively. The binary logistic regression for the prediction (1) versus not (2) of the TN was as follows: -1.463 + age * (-.029) + phosphate * 0.233 (P = .012).

Conclusion: MIBI accuracy in patients with secondary hyperparathyroidism was increased when combined with other preoperative parameters. The sensitivity was increased as patients were older and the PTH levels were lower. The specificity was increased as patients were younger and the phosphate levels were lower.