Figure 5.

Perfusion defects provide additional information and can focus the search for small subsegmental pulmonary embolism (PE) that may be easily overlooked. (a) Coronal three-dimensional three-dimenisonal spoiled gradient recalled echo shows a small perfusion defect (asterisk) within the superior segment of the right lower lobe. (b, c) Sagittal and axial reconstructed 5-mm maximum intensity projections show abrupt vascular cut-off of the subsegmental pulmonary artery supplying this area suggesting PE (arrow).