[Interstitial lung changes in high-resolution computed tomography]

Abstract

With high-resolution computed tomography (HR-CT) it is possible to localize interstitial pulmonary disease of different etiology within the secondary pulmonary lobule. This may be most successful in the periphery of these interstitial lesions where lobular architecture is best preserved. In the areas of maximal changes, pathological findings are sometimes so severe that the base structures of the lobule cannot be identified. Since abnormalities in the peripheral zone of a pathologic progress normally represent early changes, analysis of the distribution pattern may allow to describe the mode of extension and to narrow down the differential diagnosis. Detection of the pattern of abnormal densities within in the secondary pulmonary lobule enables only a morphological description. Pathognomic distributions are at present not defined radiologically. Moreover, a wide spectrum of CT findings, occasionally overlapping, may occur in interstitial diseases. Nevertheless, the described additional observations are helpful in diagnosis and allow to avoid invasive methods in selected cases. However, HR-CT is certainly useful in defining the optimal localisation of tissue sampling either by bronchoscopy or open lung biopsy. Evaluation of disease activity seems to be possible, too. Further radiological pathological correlations in larger prospective studies are necessary to define the diagnostic value of this new technique.