Bronchial wall thickness measurement in computed tomography: effect of intravenous contrast agent and reconstruction...

Bronchial wall thickness measurements in computed tomography (CT) has become a useful tool for assessment of the severity of diseaseand the response to treatment in a large number of pulmonary diseases. However, there are only few reports evaluating its dependence on different scan protocols. The effect of intravenous contrast medium has not been analyzed. The aim of this study was to evaluate the influence of intravenous contrast medium application, the contrast phase (arterial and venous) and different reconstruction kernels on bronchial wall measurements of a newly developed algorithm. The bronchial wall thickness was analyzed in 630 bronchial sections of 56 CT examinations with dedicated software (MEVIS Airway Examiner, Fraunhofer MEVIS Bremen, Germany). Application of i.v. contrast agent significantly increased bronchial wall thickness (paired t-test, p<0.001). Comparing arterial and venous phase, bronchial wall thickness was significant higher in the arterial phase (paired t-test, p=0.045). Bronchial wall thickness also increased (ANOVA with Bonferroni correction, p<0.001) when using a softer reconstruction kernel. The absolute differences in bronchial wall thickness were independent of bronchial size and generation.