Chronic diffuse infiltrative lung disease. Newer approaches.

A new scheme for description of diffuse infiltrative lung diseases using the graphic terminology of the International Labour Office Classification is described. Conventions for grading the type (rounded, or "pqr," and irregular, or "stu"), severity (profusion in 12 steps), localization of opacities, and pleural disease were retained. Modifications included (a) a third group of opacities, called "xyz," corresponding to reticulonodular patterns; and (b) "ground glass" (alveolar) patterns, subdivided into seven types by character and location. In a study of 365 cases proven by open biopsy, when this scheme was used without any knowledge of clinical data, the first two radiologic diagnostic choices corresponded with the principal histologic diagnosis in 50 per cent of cases. This classification provides an understandable and quantifiable system of communication and a tool for teaching, clinical research, and epidemiologic studies.