title: Parathyroid 99mTc-sestamibi scintigraphy: dual-tracer subtraction is superior to double-phase washout.
abstract: Technetium-99m sestamibi imaging for parathyroid adenoma localization has been performed using both dual-tracer subtraction and double-phase single-tracer washout techniques. The relative accuracy of these two techniques is uncertain. We have developed a modified imaging technique which combines both approaches and have directly compared them in a series of patients with surgically explored hyperparathyroidism. Initial injection of (99m)Tc-pertechnetate 50 MBq was followed by continuous dynamic imaging of the anterior neck for 30 min. (99m)Tc-sestamibi 1,000 MBq was injected intravenously at the midpoint of the acquisition. Delayed images were performed after 2 h. We blindly reviewed 88 consecutive cases of surgically explored hyperparathyroidism that had undergone preoperative scintigraphic localization with this procedure. Images were reformatted to display subtraction-only, early/delayed sestamibi-only and combined images. Scans were reviewed in random order. Of the 68 cases with solitary parathyroid adenoma, the sestamibi-only images gave correct localization in 49 (72%) while there was a statistically significant improvement in accuracy using the subtraction-only images (58 of 68, 85%, P=0.05) and the combined images (61 of 68, 90%, P=0.0015). Reader confidence was also greater with the subtraction-only and combined images than with the sestamibi-only images. Scan performance with parathyroid hyperplasia was less satisfactory. Although the largest gland was usually correctly identified, hyperplasia was difficult to distinguish from a solitary adenoma. Dual-tracer subtraction parathyroid imaging is superior to double-phase sestamibi-only imaging. The washout data may provide additional information in some cases, however, and an approach that combines both techniques may be optimal.
authors.affiliation: Section of Nuclear Medicine, University of Manitoba and St. Boniface General Hospital, Winnipeg, Canada. bleslie@sbgh.mb.ca
authors.forename: William D
authors.initials: WD
authors.lastname: Leslie
authors.forename: Jacqueline O
authors.initials: JO
authors.lastname: Dupont
authors.forename: Bohdan
authors.initials: B
authors.lastname: Bybel
authors.forename: Karl T
authors.initials: KT
authors.lastname: Riese
mesh_terms: D000236:Adenoma / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D006965:Hyperplasia / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D007089:Image Enhancement / Q000379:methods; D008297:Male; D008875:Middle Aged; D010282:Parathyroid Neoplasms / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013670:Sodium Pertechnetate Tc 99m; D013382:Subtraction Technique; D017256:Technetium Tc 99m Sestamibi
chemical_list: D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D013670:Sodium Pertechnetate Tc 99m