SPECT/CT's Advantage for Preoperative Localization of Small Parathyroid Adenomas in Primary Hyperparathyroidism.
OBJECTIVE
The aims of this study were to assess the performance of Tc-sestamibi SPECT/CT, with diagnostic CT quality, compared with SPECT alone for preoperative localization of parathyroid adenomas and to assess the influence of adenoma weight on the correct adenoma lateralization with SPECT/CT and with SPECT alone.


METHODS
Two hundred forty-nine consecutive patients, biochemically diagnosed with primary hyperparathyroidism, were examined with a combined SPECT/CT scanner. Subsequently, 200 patients with confirmed histopathology and biochemical cure after parathyroidectomy were included in this study (16 with multiglandular disease). For each patient, the SPECT-alone data were analyzed first. Thereafter, the CT information was added, and a new evaluation was performed with the combined data. In addition, for each patient, the diagnostic confidence with each method was graded on a scale based on the presence of different image features. The preoperative diagnostic findings were then compared with the surgical and histopathologic reports.


RESULTS
The distribution of adenoma weights showed a peak at 210 mg, with a median at 338 mg. The sensitivity and specificity (multiglandular disease included) for correct classification of adenomas were significantly higher for SPECT/CT, 83% and 96%, respectively, than for SPECT alone, 80% and 93% (P < 0.01). Below 210 mg, the differences between SPECT/CT and SPECT alone in accurate adenoma lateralization were more prominent. Sixty-seven percent of all adenomas were graded with the highest confidence score with SPECT/CT compared with 53% with SPECT.


CONCLUSIONS
SPECT/CT yields fewer false-positive findings than SPECT alone. The advantage of SPECT/CT over SPECT alone was most apparent for correct lateralization of small adenomas (<210 mg).
From the *Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital; †Department of Molecular Medicine and Surgery, Karolinska Institute; ‡Department of Endocrine Surgery, Karolinska University Hospital, Stockholm; and §Department of Radiology, Section for Molecular Imaging, Ins. Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden.
Patricia
P
Sandqvist
Inga-Lena
IL
Nilsson
Per
P
Grybäck
Alejandro
A
Sanchez-Crespo
Anders
A
Sundin
D000236:Adenoma / Q000000981:diagnostic imaging* / Q000601:surgery; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D057234:Preoperative Period; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D000072098:Single Photon Emission Computed Tomography Computed Tomography; D017256:Technetium Tc 99m Sestamibi
D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi