Diagnosing Pulmonary Embolism With Computed Tomography Pulmonary Angiography

Figures

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  FIGURE 1. Scan range boundaries: Original (a) and reduced (b) z-axis coverage on an exemplary topogram. The cranial boundary slice is set at the upper edge of the aortic knob and the caudal boundary slice at the top of the lower hemidiaphragm.

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  FIGURE 2. Flowchart of included and excluded patients. aOne scan with both reduced range and chronic PE only. bReported findings likely explained by artifacts.

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  FIGURE 3. Example of a case with both emboli within and outside the reduced range. Boundary slices of the reduced range are indicated with dashed lines in C. A, Segmental embolus in the medial segment of the middle lobe (arrow), located within the reduced range (reference line in C). B, Subsegmental embolus in the posterobasal segment of the right lower lobe (arrow), located outside the reduced range (reference line in C).

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  FIGURE 4. Example of a case with an isolated embolus outside the reduced range. Boundary slices of the reduced range are indicated with dashed lines in B. A, Subsegmental embolus in the apical segment of the right upper lobe (arrow), located outside the reduced range (reference line in B).

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  FIGURE 5. Estimated sensitivities of different boundary slice positions. Estimated sensitivity is based on the location of the most proximal thrombus end. A, Sensitivities of the cranial boundary slice to detect emboli at or above the pulmonary artery bifurcation. B, Sensitivities of the caudal boundary slice to detect emboli at or below the pulmonary artery bifurcation.

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  FIGURE 6. Missed incidental findings. Euler diagrams illustrating the frequency of incidental findings outside the reduced range (colored ellipses) in subgroups stratified by age and history of malignancy. Total n=495. A, Findings suspicious of malignancy. B, Equivocal findings. C, Potentially relevant benign findings.

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  FIGURE 7. Example of a pulsation artifact that was initially reported as PE. A, Apparently reduced contrast in a subsegmental artery of the anterior segment of the left upper lobe. B, Using a lung window a doubled contour of the vessel becomes visible. This is a typical pulsation artifact that can explain the finding.