Why? What? When? Utility of 4DCT in the preoperative imaging algorithm of primary hyperparathyroidism.

Background: 4-Dimensional computed tomography (4DCT) is a specialised examination used to locate diseased parathyroid glands in a confirmed case of primary hyperparathyroidism. Objectives: To define the role of 4DCT as a first-hand diagnostic tool in locating the abnormal parathyroid gland. Method: A retrospective cohort study of 44 patients with primary hyperparathyroidism was performed. Patients with preoperative 4DCT findings and surgical findings with histopathological results were included in the study to assess the effectiveness of 4DCT in locating the diseased parathyroid glands. Results: Of the 44 patients who underwent 4DCT, operative findings of three patients were discordant with the 4DCT findings. The calculated sensitivity of 4DCT was 93%. 4DCT was able to identify lesions in ectopic locations in two cases and missed one case in an intra-thyroidal location, misinterpreted as a suspicious thyroid lesion. The sensitivity of 4DCT in detecting multiglandular disease was 75%. Of the diagnosed parathyroid lesions, 52.1% were located on the left, 35.4% on the right and 12.5% were located bilaterally. Additionally, 76% were seen inferiorly and 24% were seen superiorly. Conclusion: 4DCT has high utility in the presurgical localisation of the eutopically or ectopically placed diseased parathyroid glands in single and multiglandular disease and also provides additional anatomical details. Contribution: 4DCT identified additional findings such as aberrant origin of right subclavian artery, which is an important pre-operative finding for the surgeon to be aware of. This study contributes to the existing literature on the role of 4DCT.