Figure 2.

Generation of VIE of pulmonary embolism with selection of appropriate CT thresholds. Upper CT threshold was selected to start at 300 HU showing the best visualization of intraluminal thrombus (long black arrows). When upper threshold was reduced to lower levels, pierced artifacts (short black arrows) appeared in the arterial wall resulting in disruption of the arterial lumen. When upper threshold was increased to 400 HU, floating artifacts (white arrows) appeared in the arterial lumen affecting visualization of thrombus. VIE, virtual intravascular endoscopy; CT, computed tomography; HU, Hounsfield unit.