The accuracy of parathyroid gland localisation in hyperparathyroidism using Tc99m-sestamibi imaging.

. We have assessed the accuracy and sensitivity of Tc 99m-MIBI (methoxy-isobutyl isonitrile) imaging in the localisation of parathyroid adenoma and hyperplasia. All patients were submitted to surgical exploration of the neck. Thirty one patients (24 F and 7 M) with clinic and biologic diagnosis of primary (no 28) and secondary (no3) hyperparathyroidism were submitted to MIBI study prior to surgical exploration of the neck. Cervico-thoracic planar imaging (anterior view, static acquisition of 10 min.) was performed at 15 min. and at 2-3 hr after intravenous injection of 444-555 MBq of MIBI. Ten out of thirty one patients were early submitted to Tc 99m perthecnetate injection (18-37 MBq) and, after 10 min., one image of 10 min. was acquired. At the processing the Tc 99m pertechnetate image was subtracted to the MIBI image. In all patients one region of interest (ROI) was drawn over the area of increased uptake corresponding to the suspect parathyroid adenoma and one over the normal thyroid parenchyma. The parathyroid adenoma or hyperplasia / normal thyroid tissue ratios were then calculated for both early and delayed imaging. Of 31 patients examined with MIBI, all of them positive to surgical exploration of the neck, 28 patients showed parathyroid focal uptake (adenoma or hyperplasia): 24 were accurately localised to the correct quadrant and 4 were correctly lateralized (SE 90%). The quantitative study has confirmed the qualitative information. Parathyroid imaging with Tc 99m MIBI (early and delayed study with differential wash-out analysis) allows a good accuracy in the preoperative detection and localisation of adenoma or hyperplasia in patients with primary or secondary hyperparathyroidism.