Quantification of lung perfusion blood volume (lung PBV) by dual-energy CT in patients with and without pulmonary embolism: preliminary results.

Abstract

Recently, software has been used for quantification of lung PBV, which can be evaluated objectively; however, this technique is yet to be validated. The purpose was to investigate the clinical feasibility of the quantification of lung perfusion blood volume (lung PBV) by dual-energy CT in patients with pulmonary embolism (PE).
One hundred thirteen patients with clinical suspicion of PE underwent dual-energy CT angiography with a standard injection protocol. Patients were divided into each two groups with and without PE based on the presence of endoluminal clots on transverse diagnostic scans. We evaluated the quantification of lung PBV using a workstation. Associations between lung PVB and the numbers of pulmonary segments with PE were also evaluated.
Thirty three of 113 (29%) patients were found to have endoluminal clots in the right and/or left lungs. The remaining 80 patients did not have endoluminal clots. In 33 patients, the mean number of segments with endoluminal clots was 5.2±3.3. For patient (whole lung)-based analysis, in patients with and without PE, mean lung PBVs were 20.8±2.3 and 28.7±6.8 Hounsfield Unit (HU), respectively, with a significant difference between the two groups (p<0.0001). In patients with PE, there was a significant correlation between lung PBV and the numbers of pulmonary segments with PE (R=0.57, p=0.0005).
The findings of this preliminary study suggest that quantification of lung PBV may reflect the pulmonary artery perfusion, which is useful to evaluate pulmonary blood flow in patients with PE.