Nonmassive acute pulmonary embolism: evaluation of the impact of pulmonary arterial wall distensibility on the assessment of the CT obstruction score.

Purpose: To evaluate the impact of pulmonary arterial wall distensibility on the assessment of a computed tomography (CT) score in patients with nonmassive pulmonary embolism (PE) (ie, Mastora score).

Materials And Methods: The arterial wall distensibility of five central pulmonary arteries (pulmonary artery trunk, right and left main pulmonary arteries, right and left interlobar pulmonary arteries) was studied on ECG-gated CT angiographic studies of the chest in 15 patients with no pulmonary arterial hypertension (group 1; mean pulmonary artery pressure: 17.2 mm Hg) and 9 patients with nonmassive PE (group 2), using 2D reconstructions at every 10% of the R-R interval.

Results: The systolic and diastolic reconstruction time windows of the examined arteries were identical in the 2 groups, obtained at 20% and 80% of the R-R interval, respectively. No statistically significant difference was observed between the mean values of the pulmonary arterial wall distensibility between the 2 groups, varying between 20.5% and 24% in group 1 and between 23.3% and 25.9% in group 2. The coefficients of variation of the average arterial surfaces were found to vary between 4.30% and 6.50% in group 1 and 4.2% and 8.4% in group 2. Except the pulmonary artery trunk in group 2, all the intraclass correlation coefficients were around 0.8 or greater than 0.8, that is the cutoff for good homogeneity of measurements.

Conclusion: The pulmonary arterial wall systolic-diastolic distensibility does not interfere with the assessment of a CT obstruction score in the setting of nonmassive PE.