Figure 5b. Septic pulmonary embolism in a 28-year-old intravenous drug abuser with human immunodeficiency viral infection. Repeated blood cultures disclosed a positive culture for Nocardia. (a) Radiograph shows multiple cavitary nodules throughout both lungs. (b) CT scan (10-mm collimation) obtained at the level of the azygos arch demonstrates the feeding vessel sign (vessel leading directly to the nodule) in several nodules (arrows).