Comparison of 4D CT, USG, and 99mTc Sestamibi SPECT/CT in Localizing Single-Gland Primary Hyperparathyroidism

Abstract

Introduction: Four-dimensional computed tomography (4D CT) provides surgeons with anatomical and functional information about parathyroid glands for minimally invasive parathyroidectomy (MIP). The purpose of this study was to evaluate the usefulness of 4D CT for localizing single-gland primary hyperparathyroidism (HPT). Methods: Twenty-four patients were selected, who underwent focused parathyroidectomy for single gland primary HPT between June 2011 and February 2013. Three imaging modalities of ultrasonography (US), 99mTc sestamibi scanning with single positron emission computed tomography/CT (SeS), and 4D CT, were performed for each patient. Data were reviewed retrospectively and imaging modalities were compared in terms of sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. Associations between correct 4D CT localization of abnormal parathyroid glands and demographic, clinical, and pathological characteristics were assessed. Results: Compared to US, 4D CT was more sensitive (91.7% vs. 62.5%

p=0.015) and specific (97.2% vs. 88.9%

p=0.05), and had higher positive predictive value (91.7% vs. 65.2%

p<0.001), negative predictive value (97.2% vs. 87.7%

p=0.021), and accuracy (95.8% vs. 82.3%

p=0.005). 4D CT did not differ significantly from SeS in terms of any measure. However, in 6/24 (25%) patients, where neither US nor SeS yielded convincing data, 4D CT provided correct localization for MIP. 4D CT localization correlated with maximal diameter (p=0.004) and volume (p=0.002) of parathyroid glands. Conclusions: 4D CT is a valuable imaging technique for detecting lesions in primary HPT. Compared to conventional imaging, including SeS, its sensitivity is similar or higher

it is also more specific than either US or SeS.