Utility of 4-dimensional computed tomography in predicting single-gland parathyroid disease—Can we abandon intraoperative parathyroid monitoring?

Background: Four-dimensional computed tomography is routinely used to localize parathyroid disease, with consistently excellent parathyroid gland localization rates reported. This study evaluated whether pairing 4-dimensional computed tomography results with preoperative clinical variables can accurately predict single-gland disease in primary hyperparathyroidism. Methods: Patients with primary hyperparathyroidism who underwent both 4-dimensional computed tomography imaging and parathyroidectomy between January 2019 and September 2021 at a large academic health system were included. Patient demographics, preoperative characteristics, and peri- and postoperative data were collected. The accuracy of 4-dimensional computed tomography in correctly identifying patients with single-gland disease with and without preoperative calcium and parathyroid hormone levels was calculated. Single-gland disease was defined by intraoperative parathyroid hormone decrease >50% and a hypercellular gland on pathology. Results: One hundred seventy-five patients had 4-dimensional computed tomography results suggestive of single gland disease. One hundred fifty-two patients (87%) were predicted correctly to have single-gland disease. The predictive accuracy increased when stratifying by preoperative calcium (≥10.5 mg/dL, ≥11 mg/dL, and ≥12 mg/dL) and parathyroid hormone levels (≥65 pg/mL, ≥100 pg/mL, and ≥200 pg/dL). The accuracy further increased when stratifying by age (≤50 years). Accuracy for single gland disease was 100% when combined with any of the following: (1) calcium ≥12 mg/dL, (2) parathyroid hormone ≥200 pg/dL, or (3) calcium ≥11 mg/dL in patients ≤50 years. Conclusion: Four-dimensional computed tomography alone accurately predicted single gland disease in 87% of patients with primary hyperparathyroidism. When combined with preoperative calcium, parathyroid hormone and age thresholds, predictive accuracy for single-gland disease approached 100%. Given the high likelihood of single-gland disease in these scenarios, clinicians may consider offering focused unilateral parathyroidectomy without intraoperative parathyroid hormone monitoring in selected patients.