Author(s)

Matthieu Pelletier-Galarneau, Oyebola O. Sogbein, Laurent Dinh, Lionel S. Zuckier

Division of Nuclear Medicine, University of Ottawa, Ottawa, Canada.

With dual-radiopharmaceutical (DR) parathyroid scintigraphy, imaging with ^99mTcO4-or ¹²³I-NaI is combined with ^99mTc-sestamibi scintigraphy for localization of parathyroid adenomas. The set images are then either visually compared or digitally subtracted to aid in interpretation. While both EANM and SNMMI guidelines recommend use of digital subtraction over visual interpretation alone, to date, the few formal comparisons performed have not demonstrated superiority. The purpose of this investigation is to rigorously assess the added value of digital subtraction over visual interpretation alone using simultaneously-acquired ¹²³I-NaI and ^99mTc-sestamibi images. Materials: 90 consecutive patients with DR parathyroid scintigraphy for primary hyperparathyroidism who underwent successful parathyroidectomy were included. DR planar acquisition was performed 15 minutes post injection using 10% dual energy windows. Digital subtraction was subsequently performed using commercially available software. Images were independently reviewed by 3 nuclear medicine trainees and 2 experienced nuclear medicine physicians with and without digital subtraction. Results were compared with surgical and histopathologic findings, which served as ground truth. Results: 90 patients had a total of 91 confirmed parathyroid lesions. All 5 readers had significantly greater sensitivity with digital subtraction compared with visual interpretation alone while specificity was not significantly diminished. Area under the ROC curve was significantly greater with digital subtraction in 3 of 5 readers. Agreement was greater among trainees and experienced physicians when using digital subtraction. Conclusion: Using an optimized DR planar co-imaging technique, digital subtraction significantly improved inter-observer agreement and confidence of interpretation and increased sensitivity, without diminishing specificity.

Parathyroid Scintigraphy, Dual-Isotope, Dual-Radiopharmaceutical, Digital Subtraction, Visual

Pelletier-Galarneau, M. , Sogbein, O. , Dinh, L. and Zuckier, L. (2015) Superiority of Digital Subtraction for Analysis of Simultaneously-Acquired Dual-Radiopharmaceutical Parathyroid Scintigraphy. Open Journal of Medical Imaging, 5, 42-48. doi: 10.4236/ojmi.2015.52007.