Percentage arterial enhancement on 2D CT in the diagnosis of primary hyperparathyroidism: A prospective validation study and potential pitfalls.

BACKGROUND: Parathyroid lesions are identified by subjective enhancement and washout patterns on computed tomography (CT). We have previously proposed "percentage arterial enhancement" (PAE) as an objective index and now aim to validate its performance prospectively. METHODS: Dual-phase CT was performed in 40 consecutive primary hyperparathyroidism patients. PAE was calculated as [{arterial phase Hounsfield unit (HU)-unenhanced phase HU}/unenhanced phase HU] × 100. PAE > 128.9% was considered parathyroid. RESULTS: PAE had 94.2% sensitivity, 100% positive predictive value (PPV) in lateralization, and sensitivity and PPV of 93.9% in quadrant localization of single-gland disease. PAE failed to identify two lesions: an intrathyroidal parathyroid carcinoma in the background of multinodular goiter and another lower enhancing cystic parathyroid adenoma. PAE had 60% sensitivity, and 100% PPV to identify multigland disease. The mean effective dose was 2.74 mSV. CONCLUSIONS: PAE is a specific CT index for parathyroid lesions with less radiation exposure. Areas of caution include intrathyroidal and cystic lesions.

Percentage arterial enhancement: An objective index for accurate identification of parathyroid adenoma/hyperplasia in primary hyperparathyroidism.

BACKGROUND: Radiation exposure to neck by four-dimensional computerized tomography (4DCT) is relatively high and limits its use as a first-line investigation in evaluation of primary hyperparathyroidism (PHPT). Radiation exposure can be reduced by restricting the number of CT phases. Our aim was to study the performance of 4DCT in cohort of surgery-naïve PHPT patients, and to evaluate percentage enhancement as an objective radiological index to discriminate parathyroid lesions (adenoma/hyperplasia) from thyroid tissue and lymph nodes. MATERIALS AND METHOD: Retrospective study of 49 PHPT patients {(44 single-gland diseases (SGD) and five multiple-gland disease (MGD)} who underwent 4DCT (unenhanced, early arterial, early venous and delayed venous phase) pre-operatively. Two radiologists who were blinded to surgical location of parathyroid lesions examined the scans. Attenuation values were recorded for parathyroid lesions (n=50), thyroid gland (n=50) and lymph nodes (n=12) in different phases. Percentage enhancement for different phases was calculated as "(HU in a specific enhanced phase-HU in unenhanced phase)/HU in unenhanced phase" ×100. RESULTS: Inter-rater reliability between the two radiologists was 0.83 (Cohen's kappa). In SGD, sensitivity and PPV were 93.18% and 98.8% for lateralization, and 89.77% and 95.18% for quadrant localization, respectively. In MGD, 4DCT showed 50% sensitivity and 100% PPV. Percentage arterial enhancement showed highest area under curve (AUC=0.992) for differentiation of parathyroid lesions from thyroid tissue and lymph nodes. A cut-off value of 128.9% showed 95.8% sensitivity and 100% specificity for the identification of parathyroid lesions. CONCLUSIONS: We propose that percentage arterial enhancement can be used as an objective radiological index for accurate identification of parathyroid adenoma/hyperplasia.

Thoracoscopic removal of impacted denture: Report of a case with review of literature.

Impacted foreign bodies in the oesophagus are common. Because of their large size, rigidity and pointed edges, dentures get frequently impacted in the oesophagus and are difficult for endoscopic retrieval. Traditional thoracotomy for retrieval of impacted foreign bodies in the thoracic oesophagus is associated with significant morbidity. We present a case of impacted denture in the mid-oesophagus successfully removed using minimal access thoracoscopic procedure.