Optimal pinhole techniques for preoperative localization with Tc-99m MIBI for primary hyperparathyroidism

Area of Science:

• Nuclear Medicine
• Radiology
• Endocrinology

Background:

• Technetium-99m-labeled 2-methoxyisobutylisonitrile (Tc-99m MIBI) is widely used for preoperative parathyroid adenoma localization.
• Imaging protocols for Tc-99m MIBI vary, necessitating optimization for diagnostic accuracy.

Purpose of the Study:

• To determine the optimal timing for delayed imaging with Tc-99m MIBI.
• To evaluate the effectiveness of routine correlative pertechnetate thyroid imaging in parathyroid localization.

Main Methods:

• Ninety-seven patients underwent dual- or triple-phase Tc-99m MIBI imaging and correlative pertechnetate thyroid imaging.
• Images were acquired at 15 minutes, 2 hours, and 4 hours post-injection.
• Two blinded nuclear medicine physicians interpreted various combinations of MIBI and thyroid images.

Main Results:

• The combination of 15-minute, 2-hour, and 4-hour Tc-99m MIBI images with thyroid scans achieved an 88% sensitivity rate.
• 15-minute and 2-hour MIBI images with thyroid scans yielded 86% sensitivity, comparable to 4-hour imaging.
• Adding correlative thyroid scans significantly improved sensitivity and reporter confidence.

Conclusions:

• A preferred protocol involves 15-minute and 2-hour Tc-99m MIBI images with correlative thyroid scanning.
• This protocol offers results similar to 4-hour imaging but in a more time-efficient manner.
• Shorter imaging times enhance logistical feasibility without compromising diagnostic performance.