Clinical Values of ^99mTc-MIBI Pinhole Dual-phase and Parallel-hole SPECT/CT for Preoperative Localization in Patients with Primary Hyperparathyroidism

  Objective  To evaluate the clinical values of preoperative ^99mTc-methoxyisobutylisonitrile (MIBI) pinhole collimator duplex imaging versus parallel-hole collimator single photon emission computed tomography (SPECT)/CT tomography fusion imaging in the preoperative localization of primary hyperparathyroidism (PHPT).

  Methods  In this diagnostic test, the patients with suspected PHPT in Peking Union Medical College Hospital from July 2021 to February 2022 were retrospectively analyzed. With postoperative histopathology as the gold standard, the sensitivity, accuracy, and positive predictive value of ^99mTc-MIBI pinhole collimator duplex imaging and parallel-hole collimator SPECT/CT tomographic fusion imaging for the detection of PHPT lesions were calculated, and the effect of parathyroid hormone (PTH) on the detection of PHPT lesions by these two diagnostic methods was analyzed.

  Results  A total of 135 patients with suspected PHPT on ^99mTc-MIBI parathyroid imaging were enrolled. A total of 149 lesions were detected on ^99mTc-MIBI pinhole collimator diachronic imaging (including 1 ectopic lesion) and 148 lesions were detected on parallel-hole collimator SPECT/CT tomographic fusion imaging (including 11 ectopic lesions; 1 true positive lesion was a fusion of 2 lesions that could not be distinguished by this method). The sensitivity (79.9% vs. 74.8%, P=0.326), accuracy (79.2% vs. 75.7%, P=0.490) and positive predictive value (98.3% vs. 100%, P=0.499) of the two methods for detecting PHPT lesions were not significantly different. In the subgroups with PTH≤150 ng/L and PTH>150 ng/L, the sensitivity (79.1% vs. 80.5%, P=0.838), accuracy (77.5% vs. 80.8%, P=0.688), and positive predictive value (96.4% vs. 100%, P=0.219) of ^99mTc-MIBI pinhole collimator diachronic imaging in detecting PHPT lesions were not significantly different; the sensitivity (71.6% vs. 77.6%, P=0.445), accuracy (73.2% vs. 77.9%, P=0.567), and positive predictive value (100% vs. 100%, P> 0.999) of SPECT/CT fusion imaging were also not significantly different.

  Conclusions  Both ^99mTc-MIBI pinhole collimator parathyroid duplex imaging and parallel-hole collimator SPECT/CT tomographic fusion imaging have good diagnostic ability for PHPT and are not significantly affected by changes in PTH levels. Due to the high resolution of ^99mTc-MIBI pinhole collimator parathyroid duplex imaging, it is still an important basis for preoperative localization and diagnosis of PHPT, while parallel-hole collimator SPECT/CT tomographic fusion imaging has obvious advantages for the diagnosis of ectopic PHPT and is recommended in some special cases.