Effect of Segmental Bronchoalveolar Lavage on Quantitative Computed Tomography of the Lung

Abstract

Rationale and Objectives With employment of both multi-detector computed tomography (MDCT) and endobronchial procedures in multi-center studies, effects of timing of endobronchial procedures on quantitative imaging (Q-MDCT) metrics is a question of increasing importance. Materials and Methods Six subjects were studied via MDCT at baseline, immediately following and at 4hrs and 24hrs post-BAL (right middle lobe (RML) and lingula). Through quantitative image analysis, non-air, or ‘tissue’ volume (TV) in each lung and lobe was recorded. Change in TV from baseline was used to infer retention and re-distribution of lavage fluid. Results Bronchoscopist reported unrecovered BAL volume correlated well with Q-MDCT for whole lung measures, but less well with individual lobes indicating redistribution. TV in all lobes except the RLL differed significantly (p<.05) from baseline immediately post lavage. At 24hrs, all lobes except the LLL (small 1% mean difference at 24hrs.) returned to baseline. Conclusions These findings suggest fluid movement, effecting Q-MDCT metrics, between lobes and between lungs before eventual resolution, and preclude protocols involving the lavage of one lung and imaging of the other to avoid interactions. We demonstrate that Q-MDCT is sensitive to lavage fluid retention and re-distribution, and endobronchial procedures should not precede Q-MDCT imaging by less than 24hrs.

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