Perfusion CT in patients with advanced bronchial carcinomas: a novel chance for characterization and treatment monitoring?

Advanced bronchial carcinomas by means of perfusion and peak enhancement using dynamic contrast-enhanced multislice CT are characterized. Twenty-four patients with advanced bronchial carcinoma were examined. During breathhold, after injection of a contrast-medium (CM), 25 scans were performed (1 scan/s) at a fixed table position. Density-time curves were evaluated from regions of interest of the whole tumor and high- and low-enhancing tumor areas. Perfusion and peak enhancement were calculated using the maximum-slope method of Miles and compared with size, localization (central or peripheral) and histology. Perfusion of large tumors (> 50 cm3) averaged over both the whole tumor (P = 0.001) and the highest enhancing area (P = 0.003) was significantly lower than that of smaller ones. Independent of size, central carcinomas had a significantly (P = 0.04) lower perfusion (mean 27.9 ml/min/100 g) than peripheral ones (mean 66.5 ml/min/100 g). In contrast, peak enhancement of central and peripheral carcinomas was not significantly different. Between non-small-cell lung cancers and small-cell lung cancers, no significant differences were observed in both parameters. In seven tumors, density increase after CM administration started earlier than in the aorta, indicating considerable blood supply from pulmonary vessels. Tumor perfusion was dependent on tumor size and localization, but not on histology. Furthermore, perfusion CT disclosed blood supply from both pulmonary and/or bronchial vessels in some tumors.

Evaluation of changes in central airway dimensions, lung area and mean lung density at paired inspiratory/expiratory high-resolution computed tomography.

The aim of this study was to improve the understanding of interdependencies of dynamic changes in central airway dimensions, lung area and lung density on HRCT. The HRCT scans of 156 patients obtained at full inspiratory and expiratory position were evaluated retrospectively. Patients were divided into four groups according to lung function tests: normal subjects ( n=47); obstructive ( n=74); restrictive ( n=19); or mixed ventilatory impairment ( n=16). Mean lung density (MLD) was correlated with cross-sectional area of the lung (CSA(L)), cross-sectional area of the trachea (CSA(T)) and diameter of main-stem bronchi (D(B)). The CSA(L) was correlated with CSA(T) and D(B). MLD correlated with CSA(L) in normal subjects ( r=-0.66, p<0.0001) and patients with obstructive ( r=-0.62, p<0.0001), restrictive ( r=-0.83, p<0.0001) and mixed ventilatory impairment ( r=-0.86, p<0.0001). The MLD correlated with CSA(T) in the control group ( r=-0.50, p<0.0001) and in patients with obstructive lung impairment ( r-0.27, p<0.05). In patients with normal lung function a correlation between MLD and D(B) was found ( r=-0.52, p<0.0001). CSA(L) and CSA(T) correlated in the control group ( r=0.67, p<0.0001) and in patients with obstructive lung disease ( r=0.51, p<0.0001). The CSA(L) and D(B) correlated in the control group ( r=0.42, p<0.0001) and in patients with obstructive lung disease ( r=0.24, p<0.05). Correlations for patients with restrictive and mixed lung disease were constantly lower. Dependencies between central and peripheral airway dimensions and lung parenchyma are demonstrated by HRCT. Best correlations are observed in normal subjects and patients with obstructive lung disease. Based on these findings we postulate that the dependencies are the result of air-flow and pressure patterns.