Can thallium-pertechnetate subtraction scanning play a role in the preoperative imaging for minimally invasive parathyroidectomy?

PURPOSE: Preoperative Tc-99m sestamibi scanning can identify candidates for minimally invasive parathyroid surgery. However, a significant number of patients with single gland disease have negative scans and are not considered for the minimally invasive procedure.

MATERIALS AND

METHODS

To determine if T1-201/Tc-99m sodium pertechnetate subtraction scanning (TPSS) is a viable alternative imaging technique for patients with primary hyperparathyroidism (1 degrees HPTH), we reviewed our experience. The outcomes of 100 consecutive patients with 1 degrees HPTH who underwent preoperative TPSS and parathyroid exploration between 1995 and 2000 at our institution were retrospectively reviewed.

RESULTS

The mean preoperative calcium and parathyroid hormone levels were 10.8 mg/dL and 220 pg/mL, respectively. The overall cure rate was 96%. Single gland disease was present in 88%. Of the 100 patients studied, 15 underwent both a Tc-99m sestamibi scan and TPSS, whereas the other 85 had only the TPSS.

CONCLUSIONS

The sensitivity and positive predictive value of the TPSS were 73.3% and 90.4%, respectively. In the patients undergoing both TPSS and Tc-99m sestamibi scans, the results concurred in 60%. However, in 20% of the remaining patients, TPSS correctly localized the abnormal parathyroid(s) when Tc-99m sestamibi failed. TPSS has a comparable sensitivity and positive predictive value to Tc-99m sestamibi scanning. In patients with a negative Tc-99m sestamibi scan, TPSS can provide additional localizing information. As a result of the high positive predictive value of TPSS, a single parathyroid gland localized by TPSS alone can then be approached by minimally invasive parathyroidectomy.