ORIGINAL ARTICLE ACCURACY OF TECHNETIUM-99M SPECT-CT HYBRID IMAGES IN PREDICTING THE PRECISE INTRAOPERATIVE ANATOMICAL LOCATION OF PARATHYROID ADENOMAS Luke Harris, MD, 1 John Yoo, MD, FRCSC, 2 Albert Driedger, MD, PhD, FRCPC, 3 Kevin Fung, MD, FRCSC, 2 Jason Franklin, MD, FRCSC, 2 Daryl Gray, MD, FRCSC, 4 Ronald Holliday, MD, FRCSC 4 1 Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada 2 Department of Otolaryngology, Division of Head and Neck Oncology and Reconstructive Surgery, London Health Sciences Centre, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada. E-mail: john.yoo@lhsc.on.ca 3 Department of Nuclear Medicine and Radiology, Division of Nuclear Medicine, London Health Sciences Centre; London, Ontario, Canada 4 Department of Surgery, Division of General Surgery, London Health Sciences Centre, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada Accepted 5 July 2007 Published online 4 December 2007 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/hed.20727 Abstract: Background. This study evaluated the accuracy of single photon emission computed tomography (SPECT)- CT imaging for the preoperative localization of parathyroid adenomas. Methods. This study included both a quantitative and quali- tative accuracy measure. The quantitative measure was the dis- tance between the location of the adenoma on the SPECT-CT scan and the location of the adenoma intraoperatively. Qualita- tively, surgeons were asked whether or not the adenoma was in the exact location predicted by the SPECT-CT scan. The time from initial incision to identification of the parathyroid was recorded. Patients referred to London Health Sciences Centre for a suspected parathyroid adenoma were eligible for this study. Results. Twenty-three patients participated in this study. Eighteen (78.3%) had a single adenoma, 2 (8.7%) had double adenomas, and 3 (13.0%) had multiglandular hyperplasia. SPECT-CT correctly detected and localized 16 of 18 (88.9%) cases of single parathyroid adenomas. The mean distance between the location of the adenoma on the SPECT-CT scan and the location of the adenoma intraoperatively was 16.3 mm (95%  19.0 mm). For single adenomas, the median time from skin incision to identification was 14 minutes (range, 8–40 minutes). The preoperative detection and localization of a single focus of sestamibi uptake yielded a parathyroid adenoma in the specified location in 80.0% of cases (95% CI, 97.4–66.5%). Conclusions. SPECT-CT predicted the intraoperative loca- tion of a single parathyroid adenoma within 19.0 mm with 95% confidence. The correct detection and localization of multigland- ular disease remains difficult. V V C 2007 Wiley Periodicals, Inc. Head Neck 30: 509–517, 2008 Keywords: SPECT-CT; parathyroid adenoma; primary hyper- parathyroidism; accuracy; operative time Primary hyperparathyroidism (PHPT), a disease of excessive parathyroid hormone secretion that leads to chronic hypercalcemia, is most commonly caused by a parathyroid adenoma. A recent meta- analysis by Ruda et al 1 includes 20,225 cases of PHPT from 1995 to 2003 and reports that solitary Correspondence to: J. Yoo V V C 2007 Wiley Periodicals, Inc. Accuracy of Technetium-99m SPECT-CT Hybrid Images HEAD & NECK—DOI 10.1002/hed April 2008 509