Diagnostic value of dual-phase ⁹⁹Tcm-MIBI scintigraphy in patients with ectopic secondary hyperparathyroidism

Objective: To compare the diagnostic value of dual-phase ⁹⁹Tcm-MIBI scintigraphy and color Doppler ultrasonography for localizing ectopic parathyroid lesions in patients with HPT secondary to chronic renal failure (CRF-HPT). Methods: Medical records of 368 CRF-HPT patients (204 males, 164 females, age range: 12-76 years) from January 2011 to April 2015 were retrospectively analyzed. Pathological results was used as the gold standard for the diagnosis of HPT. The sensitivity and specificity of dual-phase ⁹⁹Tcm-MIBI scintigraphy and color Doppler ultrasonography for the diagnosis and localization of ectopic parathyroid lesions were studied and compared by χ² test. Results: A total of 1398 positive lesions were found in 356 patients by dual-phase ⁹⁹Tcm-MIBI scintigraphy, and 54 ectopic lesions occupying 3.9%(54/1398) of positive lesions were detected by delayed planar imaging or SPECT/CT fusion imaging in 45 patients. Most of them (n = 53) were confirmed by pathology. While only 966 positive lesions were found in 254 patients and no ectopic lesions were identified by color Doppler ultrasonography. The diagnostic sensitivity and specificity of dual-phase ⁹⁹Tcm-MIBI scintigraphy for CRF-HPT lesions were 97.2%(1375/1415) and 53.1%(26/49), respectively. The corresponding parameters of color Doppler ultrasonography were 66.4%(940/1415) and 46.9%(23/49), respectively. The specificity of ectopic lesion localization by radionuclide imaging was 98.1%(53/54). The accuracy of dual-phase ⁹⁹Tcm-MIBI scintigraphy was significantly higher than that of color Doppler ultrasound in lesion localization (χ² = 20.8, P < 0.05). Conclusion: Compared to color Doppler ultrasonography, ⁹⁹Tcm-MIBI scintigraphy is more sensitive in identifying the positive lesions and more specific in localizing the ectopic parathyroid lesions in patients with CRF-HPT. (authors)