Computed tomographic evaluation of mediastinal masses/lesions with contrast enhancement and correlation with pathological diagnosis - a study of 120 cases

Objective: The study was conducted to diagnose the mediastinal lesions/masses by computed tomographic on contrast enhanced scans and findings were compared with pathological diagnosis wherever possible. Methods: Contrast Enhanced Computed Tomography (CECT) of chest done in supine position in inspiration with 60 to 120 ml of 300 mg/ml of nonionic iodinated contrast and images were viewed in lung window (level 700 HU; width 1,500 HU), mediastinal window (level 30 HU-50 HU; width 350 HU-500 HU) and bone window (level 2,400 HU; width 200 HU). Results: The most common compartment to be involved was anterior mediastinum (38.3%) followed by posterior (16.7%), middle (13.3%) and superior mediastinum (11.7%) in that order. Predominant lesions were benign. The commonest lesion was tubercular lymphadenopathy (15%). Thymic masses and metastatic lymph node (26% each) were the most common mediastinal lesions in the anterior mediastinal compartment. Neural tumors (50%), esophageal carcinoma (37.5%) and thyroid masses (85.7%) were the common lesions in posterior, middle and superior mediastinal compartments respectively. Ascending aortic aneurysm was the predominant vascular lesion in our study (6.7%). Out of total 120 cases, 102 cases were histologically verified, six cases with hiatal hernia were confirmed with endoscopy while in 12 cases of vascular origin, and definitive diagnosis was established with Computed tomography (CT) scan alone. Conclusions: CT scan can distinguish specific tissue densities and its ability to display mediastinum in axial plane makes it a useful technique in the evaluation of a mediastinal mass.