Four-dimensional computed tomography for parathyroid localization: a new imaging modality.

INTRODUCTION

Four-dimensional computed tomography (4DCT) is a new parathyroid localization technique not previously reported in Australia. It provides both functional and anatomical imaging in a single test, with superior sensitivity compared with sestamibi scintigraphy (SeS). This study examines the utility of 4DCT in defined clinical situations.

METHODS

This is a retrospective cohort study in a tertiary referral hospital setting. One hundred consecutive operative cases of primary hyperparathyroidism (99 patients) undergoing both preoperative 4DCT and SeS. Localization studies were correlated with operative findings, histopathology and clinical outcomes. The utility of 4DCT was analysed in three common clinical settings: primary cases with positive SeS (Group A, n = 68), primary cases with negative SeS (Group B, n = 21) and re-operative cases (Group C, n = 11).

RESULTS

The overall sensitivity of 4DCT was 92% compared with 70% for SeS. The sensitivity of 4DCT was superior to SeS in Groups B and C (76% versus 0% and 91% versus 46%, respectively). The overall cure rate was 98%, with 94% of cases completed as minimally invasive procedures. Up to 62% of Group B cases potentially avoided a bilateral neck exploration owing to a positive 4DCT.

CONCLUSIONS

4DCT is an accurate technique providing both functional and anatomical localization of abnormal parathyroid glands. However, the advantage of speed and simplicity in image acquisition needs to be balanced against the small risk of increased radiation exposure in the younger patient group.