Primary Lung Cancer: Utility of Contrast-enhanced Dynamic CT in Diagnosis with Histopathologic Correlation

Seon, Hyun Ju

Abstract

To evaluate the potential role of dynamic incremental computed tomography (CT) in diagnosis of primary lung cancer by investigation of the dynamic enhancement patterns. Forty patients with presumed lung cancer (diameter<30 mm) were collected for the dynamic incremental chest CT scanning. Histopathologic confirmations were obtained by surgical excision and transthoracic needle biopsy. CT scans were performed at the region of interest (ROI) of lung nodule before and after contrast enhancement. Dynamic incremental scans after contrast enhancement were performed at 30 seconds, 60 seconds, 90 seconds, 2 minutes, 3 minutes, 4 minutes. The degree of contrast enhancement according to the time course and the time of maximum enhancement of malignant nodules were recorded, by measuring Hounsfield Unit (HU) of the nodules at the ROI. We assessed the differences of contrast enhancement patterns among the histopathologic subtypes of lung cancer. Primary lung carcinomas were diagnosed in all patients, the majority of which were squamous cell carcinoma, followed by adenocarcinoma, small cell carcinoma, bronchioloalveolar carcinoma, and large cell carcinoma. The average time of maximum contrast enhancement was 62.2+/-16.2 seconds, and the average degree of maximum contrast enhancement was 66.4+/-22.17 HU. Most primary lung cancer showed rapid contrast enhancement with slow washout. The differences of the enhancement patterns among the histopathologic subtypes were not statistically significant (p>0.05). Dynamic incremental chest CT was useful in diagnosis of primary lung cancer that showed established dynamic contrast enhancement pattern regardless of histopatholgic subtypes.