A radiographic classification for sarcoidosis: physiologic correlation.

The chest roentgenogram is frequently used to judge severity and course of sarcoidosis. The only widely used method for staging, suggested by Siltzbach, does not provide for such judgments. Therefore, we devised a scheme for objective description of type and quantity of opacities based on the ILO/UC Classification for the Pneumoconioses. We added a "reticulonodular" category (x y z) to the present "rounded (p q r) and "linear-irregular" (s t u) categories. We retained the 11 point scale for profusion (severity) and added notations to describe ground glass (alveolar) patterns, size of nodes, and hilar retractions. Among 211 patients, x y z (35%) and p q r (33%) opacities predominated while s t u opacities (19%) were unusual. Radiographic severity correlated best with vital capacity (rs = -0.49) and the diffusing capacity (rs = -0.32). With the Siltzbach classification these correlations were not as good (rs = -0.27 and -0.19). Siltzbach Stage III (fibrosis) was a distinct group with poor function and frequent airway obstruction. There was no correlation between radiographic appearance and pathologic severity because the latter grading, on a scale from 0 to 10, never exceeded 3. Sequential studies in 64 patients showed that, when individuals are used as their own controls, overall profusion correlated highly with physiologic changes over time.