FIGURE 1.

Radiological diagnosis. Computed tomography pulmonary angiography in a 71-year-old woman with progressive shortness of breath, a positive ventilation/perfusion study (not shown) and a mean pulmonary arterial pressure of 38 mmHg. a) Lung windows demonstrate striking mosaic lung attenuation with alternating areas of normal density perihilar lung and hypodense peripheral lung (asterisks). b) Despite this, there is no chronic pulmonary embolism evident in the proximal vasculature. c) Thin sections are critical to identify subtle pulmonary artery filling defects as seen here in the inferior lingula (arrow) and d) sagittal multiplanar reformats are key in revealing subtle eccentric wall thickening in the right lower lobe (arrowhead).