Diagnostic performance of ultrasonography, dual-phase (99m)Tc-MIBI scintigraphy, early and delayed (99m)Tc-MIBI SPECT/CT in preoperative parathyroid gland localization in secondary hyperparathyroidism

BACKGROUND: Secondary hyperparathyroidism (SHPT) usually requires parathyroidectomy when drug regimens fail. However, obtaining an exact preoperative map of the locations of the parathyroid glands is a challenge. The purpose of this study was to compare the diagnostic performance of US, dual-phase (99m)Tc-MIBI scintigraphy, early and delayed (99m)Tc-MIBI SPECT/CT in patients with SHPT. METHODS: Sixty patients with SHPT who were undergoing dialysis were evaluated preoperatively by US, dual-phase (99m)Tc-MIBI scintigraphy, early and delayed (99m)Tc-MIBI SPECT/CT. Postoperative pathology served as the gold standard. The sensitivity, specificity, and accuracy were determined for each method. Spearman correlation analysis was used to analyse the correlation of hyperplastic parathyroid calcification with serum alkaline phosphatase (ALP) and parathyroid hormone (PTH). RESULTS: A total of 229 lesions in 60 patients were pathologically confirmed to be parathyroid hyperplasia, with 209 lesions in typical sites, 15 lesions in the upper mediastinum and 5 lesions in the thyroid. A total of 88.33% (53/60) of patients had four lesions. US, early and delayed (99m)Tc-MIBI SPECT/CT had significantly higher sensitivity and accuracy than dual-phase (99m)Tc-MIBI scintigraphy (P < 0.001). Furthermore, early (99m)Tc-MIBI SPECT/CT had significantly higher sensitivity (P < 0.001) and accuracy (P = 0.001 and P < 0.001) than US and delayed (99m)Tc-MIBI SPECT/CT. In patients with ectopic hyperplastic parathyroid glands, the sensitivity of early (99m)Tc-MIBI SPECT/CT (90%) was significantly higher than that of US (55%) and dual-phase (99m)Tc-MIBI scintigraphy (50%) (P < 0.05). The Spearman correlation results showed a significant albeit weak association between calcification and both serum PTH and ALP (P = 0.002). CONCLUSION: The ability of early (99m)Tc-MIBI SPECT/CT to detect hyperplastic parathyroid glands in patients with SHPT is superior to that of US, dual-phase (99m)Tc-MIBI scintigraphy and delayed (99m)Tc-MIBI SPECT/CT; furthermore, dual-phase (99m)Tc-MIBI SPECT/CT is not essential.