dark bronchus sign: HRCT diagnosis of pneumocystis carinii pneumonia

We report the importance of the 'dark bronchus' sign in the diagnosis of uniform, diffuse ground glass opacification on high resolution computerized tomography [HRCT]. This sign is useful to identify diffuse ground glass opacity on HRCT in cases of Pneumocystis carinii pneumonia who may present with a normal or equivocal chest radiograph in the early course of disease