Efficacy of focused parathyroidectomy (FP) in primary hyperparathyroidism (PHPT) due to solitary adenoma, is based on an accurate preoperative localization workup, ideally combined with intraoperative intact parathyroid hormone measurement (iPTH). 4DCT has emerged as a valuable tool, enhancing preoperative planning.

Retrospective study of all consecutive patients with PHPT operated with FP by the same surgeon between 2017 and 2023, with iPTH. To evaluate the efficacy of 4D CT in the detection and localization of parathyroid adenomas.

With average of 61 years [33-85], 99 patients were evaluated, 84.8% female. Only 13.1% asymptomatic, 96,9% operated as one day surgery. Ultrasound (US) performed in 100% (n=99), with 82.8% sensitivity. Intraoperatively, an adenoma completely concordant with the quadrant was found in 85.3% (n=70); 12.1% (n=10) showed concordance regarding side but not vertical position. 4DCT performed in 90% (n=89), with 97.7% sensitivity. Intraoperatively, complete concordance with the quadrant was 88.5% (n=77); 9.2% (n=7) showed concordance regarding side but not vertical position. 4DCT showed complete agreement with surgical findings in the 17 patients with negative US. Four were adenomas in ectopic positions. The adenomas identified by US had an average diameter greater than those only identified by 4D CT (17.1mm [4-70mm] vs 15.4mm [10-23mm]; p=0.09), although not statistically significant. iPTH decreased in 98 patients (average pre-op 221.3 pg/ml to post-op 62.9 pg/ml), with normalization of calcemia at last follow-up (average 12.9 to 9.4 mg/dl).

In this series 4DCT presented with 97.7% sensitivity and very high quadrant concordance, establishing itself as a robust localizing imaging modality. When associated with iPTH, it allows for extremely effective focused parathyroidectomy.