Value of 99mTc-MIBI SPECT/CT parathyroid imaging and ultrasonography for concomitant thyroid carcinoma.

PURPOSE: We aimed to assess the frequency of carcinoma in cases with suspected parathyroid adenoma and test the value of Tc-methoxyisobutylisonitrile (Tc-MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT) parathyroid imaging and neck ultrasonography in detecting concomitant thyroid carcinoma.

PATIENTS AND

METHODS

We enrolled 741 patients with clinically suspected parathyroid adenoma who underwent Tc-MIBI planer scans and SPECT/CT of the skull base, neck, and thorax; patients also underwent ultrasonography within 1 month before SPECT/CT. Each case with suspected lesion was analyzed and correlated with pathology. We estimated the frequency of carcinoma detection on SPECT/CT performed for suspected parathyroid adenoma. The sensitivity, specificity, and accuracy of detecting thyroid carcinoma were estimated for both SPECT/CT and ultrasonography.

RESULTS

In total, 222 patients with 250 pathology results were assessed. Of these, 54 patients showed carcinoma. With respect to the anatomical distribution of the incidental findings, 19 (35.19%) had parathyroid carcinoma, 20 (37.04%) had papillary thyroid carcinoma, three (5.56%) had follicular thyroid carcinoma, six (11.11%) had medullary thyroid carcinoma, and six (11.11%) had other carcinomas. For thyroid carcinoma detection, the sensitivity, specificity, and accuracy were 35.71, 88.16, and 80.49% for SPECT/CT and 73.81, 95.10, and 91.99% for ultrasonography, respectively.

CONCLUSION

The frequency of carcinoma is high on Tc-MIBI SPECT/CT performed for suspected parathyroid adenoma. Although Tc-MIBI SPECT/CT plays an important role in the diagnosis and location of parathyroid adenoma, ultrasonography appears to be more suitable for identifying a concomitant thyroid carcinoma. This may vitally influence the choice of therapeutic regimen in patients with primary hyperparathyroidism.