Wu et al used CT angiography of pulmonary arteries to develop an index for evaluating a patient with pulmonary embolus (PE). This PE index is a measure of the size, extent and burden of the embolic disease, which correlates with outcome. The authors are from Brown Medical School in Providence, Rhode Island.

CT method: helical CT


Pulmonary segments, right lung:

(1) right superior lobe, apical

(2) right superior lobe, posterior

(3) right superior lobe, anterior

(4) right middle lobe, lateral

(5) right middle lobe, medial

(6) right lower lobe, superior (apical)

(7) right lower lobe, medial basal

(8) right lower lobe, anterior basal

(9) right lower lobe, lateral basal

(10) right lower lobe, posterior basal


Pulmonary segments, left lung:

(1) left superior lobe, apical

(2) left superior lobe, posterior

(3) left superior lobe, anterior

(4) left lingula, superior

(5) left lingula, inferior

(6) left lower lobe, superior (apical)

(7) left lower lobe, medial basal

(8) left lower lobe, anterior basal

(9) left lower lobe, lateral basal

(10) left lower lobe, posterior basal


Occlusion of the Segmental Artery




1 - 99%


100% (complete)



total score for each lung =

= SUM(points for all 10 segmental arteries)


percent occlusion in both lungs (CTPE index) =

= (total score) / 40 * 100%



• minimum score for each lung: 0

• maximum score for each lung: 20

• maximum score for both lungs: 40

• The mortality rate was 83% for patients with an CTPE index > 60%.

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