Localization of a Parathyroid Adenoma by the Addition of Pinhole Imaging to Tc-99m Sestamibi Dual-Phase Scintigraphy

Scintigraphy using Tc-99m has been shown to be highly sensitive in localizing abnormal parathyroid glands in patients with hyperparathyroidism. False-negative studies most often are attributed to glandular size or location. The authors report a case of negative parathyroid imaging using standard dual-phase technique, which was converted to a positive study by the addition of a pinhole view. During a 1-year period, the authors systematically added an anterior-pinhole image of the neck to all equivocal or negative Tc-99m studies. Five of 19 patient studies were pinhole-image positive and standard-image negative or equivocal. In selected patients undergoing Tc-99m scintigraphy for hyperparathyroidism, the addition of a pinhole view may enhance study sensitivity and the confidence in interpretation.