Determinants of Tc-99m sestamibi SPECT scan sensitivity in primary hyperparathyroidism.
BACKGROUND
The aim of this study was to evaluate the influence of patient and adenoma characteristics on (99m)Tc-methoxy isobutyl isonitrile (MIBI) scan performance in individuals diagnosed with primary hyperparathyroidism (PHP).


METHODS
Records of patients undergoing parathyroidectomy for PHP over 6 years at a single center were reviewed.


RESULTS
The overall true-positive (TP) rate for (99m)Tc-MIBI scans was 56%. Adenomas sized 1.9 to 3.5 cm were more likely to have TP scans than 0.3-cm to 1.8-cm adenomas (74% vs 40%, P < .001). Preoperative ionized calcium levels between 1.49 and 1.72 mmol/L were more likely to have TPs than levels between 1.27 and 1.48 mmol/L (65% vs 47%, P < .05). No single class of medication was shown to significantly effect TP rates. A decrease in TP rate was observed for larger adenomas in patients on >or=1 medication (74% vs 65%, P = .05).


CONCLUSIONS
In PHP, (99m)Tc-MIBI scan positivity is most related to adenoma size and preoperative ionized calcium level.
Swanson
Todd W
TW
Department of Surgery, St Paul's Hospital & University of British Columbia, Vancouver, BC, Canada.
Chan
Simon K
SK
Jones
Steven J
SJ
Bugis
Samuel
S
Irvine
Robert
R
Belzberg
Allan
A
Levine
Daniel
D
Wiseman
Sam M
SM
D000236:Adenoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D000368:Aged; D015331:Cohort Studies; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D016105:Parathyroidectomy / Q000379:methods; D011300:Preoperative Care / Q000379:methods; D011336:Probability; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D016896:Treatment Outcome
D017256:Technetium Tc 99m Sestamibi