Figure 5a. Acute pulmonary embolism in a 45-year-old woman who presented with chest pain. (a) CT scan shows a pulmonary embolus that affects the segmental artery of the laterobasal segment of the right lower lobe. This partial filling defect surrounded by contrast material produces the polo mint sign (arrow). (b) CT scan shows acute emboli that affect subsegmental arteries of the laterobasal segment (arrows).