Value of 99Tcm-MIBI SPECT/CT in pre-operative diagnosis of primary and secondary hyperparathyroidism

Objective To evaluate the value of pre-operative 99Tcm-MIBI SPECT/CT in patients with HPT by comparing with planar 99Tcm-MIBI and ultrasound imaging. Methods A total of 57 patients (9 males, 48 females; average age: (52.9±15.5) years) were enrolled into this retrospective study. They all underwent 99Tcm-MIBI planar scintigraphy, 99Tcm-MIBI SPECT/CT and ultrasound during March to October in 2016. All patients received parathyroidectomy and the surgical pathology was considered as the gold standard. The diagnostic efficiencies were compared using χ2 test. Results A total of 86 HPT lesions were confirmed, including 47 lesions in 46 PHPT patients and 39 lesions in 11 SHPT patients. The sensitivities of SPECT/CT, planar, ultrasound and combined imaging (planar plus ultrasound) were 87.21%(75/86), 69.77%(60/86), 65.12%(56/86) and 84.88%(73/86), respectively. The overall sensitivity of SPECT/CT was significantly higher than that of individual planar imaging and that of ultrasound (χ2 values: 4.691 and 7.818, both P 0.05). No significant difference was observed among the specificities of all these modalities (χ2=2.219, P>0.05). For PHPT lesions, the sensitivities of SPECT/CT, planar imaging, combined imaging and ultrasound were 95.74%(45/47), 93.62%(44/47), 97.87%(46/47) and 76.60%(36/47), respectively. No statistically significant difference was found in the sensitivity of the former 3 modalities (χ2=1.044, P>0.05), but the sensitivity of ultrasound was the lowest(χ2=16.223, P 0.05). Only SPECT/CT could accurately localize 5 ectopic HPT lesions. Conclusion Compared to planar imaging and ultrasound, SPECT/CT has higher sensitivity for SHPT patients, and could provide precise localization for ectopic lesions, thus facilitating patient planning for minimally invasive surgery. Key words: Hyperparathyroidism; Tomography, emission-computed, single-photon; Tomography, X-ray computed; Technetium Tc 99m sestamibi