Parameters in the prediction of the sensitivity of parathyroid scanning.
OBJECTIVE
Although parathyroid scintigraphy with technetium-99m sestamibi has been shown to be a sensitive and specific test for the detection and localization of parathyroid adenomas in patients with primary hyperparathyroidism, false-negative studies occur. Our goal was to determine whether the presurgical parathyroid hormone level could be used to predict whether a scan would be positive or negative.


METHODS
A retrospective review of parathyroid scans was performed. Analysis included patients with surgical confirmation of a parathyroid adenoma and a documented parathyroid hormone (PTH) level obtained within 6 months of the scan. Patients with secondary hyperparathyroidism were excluded. A true-positive study was defined by the surgical finding of an adenoma on the side indicated by the scan. A scan was false-negative if it did not detect the adenoma found at surgery. A scan was false-positive if an adenoma was identified in the wrong side of the neck or if an adenoma was called but not found.


RESULTS
Of 166 scans, 83 met the criteria for inclusion. There were 56 true-positives, 21 false-negatives, and 6 false-positives. The mean PTH in patients with true-positive scans was 367 pg/mL (range, 46-3231 pg/mL) and with false-positive and false-negative scans was 148 pg/mL (range, 46-390 pg/mL). The difference was statistically significant.


CONCLUSIONS
There is a correlation between the sensitivity of parathyroid scintigraphy and presurgical PTH. The overlap, however, of parathyroid hormone levels in positive and negative scans does not allow one to confidently preselect candidates for preoperative scanning.
Siegel
Alan
A
Department of Radiology, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA. alan.h.siegel@hitchock.org
Alvarado
Michael
M
Barth
Richard J
RJ
Brady
Matthew
M
Lewis
Jill
J
D000236:Adenoma / Q000097:blood* / Q000000981:diagnostic imaging*; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D010281:Parathyroid Hormone / Q000097:blood*; D010282:Parathyroid Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D010281:Parathyroid Hormone