Parathyroid Computed Tomography Angiography: Early Experience with a Novel Imaging Technique in Primary Hyperparathyroidism

Abstract

Objectives: To describe parathyroid computed tomography angiography (PCTA), determine its accuracy, and, as a secondary objective, calculate its mean radiation dosimetry.

Study design: Retrospective chart review of patients who underwent parathyroidectomy for primary hyperparathyroidism from 2007 to 2015.

Setting: Single-center tertiary care academic military hospital.

Subjects and methods: PCTA is a 2-phase computed tomography imaging technique that uses individualized timing of contrast infusion and novel patient positioning to accurately identify parathyroid adenomas. Consecutive patients who underwent parathyroidectomy for primary hyperparathyroidism from 2007 to 2015 were reviewed; 55% of patients were women. The mean age was 50.9 years (range, 26-68 years). Sensitivity and specificity were calculated as well as mean radiation dosimetry and timing of contrast.

Results: A total of 108 procedures were performed during the study period. Twenty-one patients undergoing 22 PCTAs after prior sestamibi scans were nonlocalizing or equivocal. In this group, there were 15 true-positive, 3 false-positive, 4 true-negative, and 0 false-negative PCTAs. This represents a sensitivity of 100% (95% CI, 74.7%-100%) and a specificity of 57% (95% CI, 20%-88%). The mean calculated radiation dose was 5.15 mSv. In the most recent studies, a mean dose of 4.1 mSv was calculated. The ideal time of image acquisition contrast administration varied from 20 to 30 seconds after contrast infusion.

Conclusions: PCTA is a new technique in anatomic imaging for hyperparathyroidism. In a single-center, single-radiologist retrospective study, it demonstrates excellent accuracy for patients with parathyroid adenomas that are otherwise difficult to localize preoperatively. Preliminary experience suggests that its use may be indicated as a primary imaging modality in the future.

Keywords: CT angiography; computed tomography; parathyroid surgery; preoperative imaging; primary hyperparathyroidism.