Preschooler with leukemia who is febrile Pediatric Imaging Chest May 25, 2026March 19, 2026 CXR PA (left) shows a triangular dense opacity in the lateral aspect of the right upper lobe that on the CXR lateral (right) is seen to be posterior in location. The diagnosis was bacterial pneumonia in the posterior segment of the right upper lobe. Related Published May 25, 2026March 19, 2026