Submitted:
17 December 2025
Posted:
23 December 2025
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Abstract
Background/Objectives: Accurate preoperative localization of hyperfunctioning parathyroid tissue is essential for minimally invasive parathyroidectomy. Conventional planar dual-phase 99mTc-sestamibi scintigraphy is widely used but shows reduced diagnostic accuracy in patients with thyroid nodules or ectopic glands. Hybrid triple-head SPECT/CT integrates functional and anatomical imaging and may improve lesion detection. This study evaluated the diagnostic performance of triple-head SPECT/CT compared with planar scintigraphy and explored correlations between biochemical markers and imaging positivity. Methods: A retrospective single-center study included 90 adults referred for suspected primary hyperparathyroidism between January 2021 and August 2025. Demographic data, laboratory parameters (PTH, total and ionized calcium, 25-hydroxyvitamin D), and imaging results were collected. Diagnostic accuracy was assessed in patients with surgical confirmation or robust clinical verification. Correlations between biochemical markers and imaging positivity were analyzed using Pearson correlation coefficients. Results: SPECT/CT demonstrated significantly higher sensitivity than planar scintigraphy (62.5% vs. 14.3%) and an excellent negative predictive value (95.1%), whereas planar imaging showed slightly higher specificity (79.5%). Ionized calcium correlated significantly with SPECT/CT positivity (r = 0.39; p = 0.009), while PTH and 25-hydroxyvitamin D showed no significant association. SPECT/CT accurately localized ectopic parathyroid glands and lesions in patients with coexisting thyroid nodularity, overcoming limitations of planar imaging. Several lesions undetected by planar scintigraphy were identified on SPECT/CT, supporting its role in anatomically complex or subtle cases. Conclusions: Triple-head SPECT/CT provided superior diagnostic performance over planar scintigraphy for preoperative localization in primary hyperparathyroidism, particularly in patients with thyroid nodularity or ectopic glands. Ionized calcium may serve as a complementary predictor of lesion detectability. These findings support hybrid SPECT/CT as the preferred first-line imaging modality, facilitating targeted minimally invasive surgery and optimizing surgical planning.
