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. 2022 Jun 8:9:100428.
doi: 10.1016/j.ejro.2022.100428. eCollection 2022.

Lobar pulmonary perfusion quantification with dual-energy CT angiography: Interlobar variability and relationship with regional clot burden in pulmonary embolism

Hye Ju Lee  1 , Mark Wanderley  1 , Vivian Cardinal da Silva Rubin  1 , Ana Clara Tude Rodrigues  2 , Amanda Rocha Diniz  2 , Jose Rodrigues Parga  1 , Marcelo Britto Passos Amato  3
Affiliations

Lobar pulmonary perfusion quantification with dual-energy CT angiography: Interlobar variability and relationship with regional clot burden in pulmonary embolism

Hye Ju Lee et al. Eur J Radiol Open. .

Abstract

Purpose: Semi-automated lobar segmentation tools enable an anatomical assessment of regional pulmonary perfusion with Dual-Energy CTA (DE-CTA). We aimed to quantify lobar pulmonary perfusion with DE-CTA, analyze the perfusion distribution among the pulmonary lobes in subjects without cardiopulmonary diseases and assess the correlation between lobar perfusion and regional endoluminal clots in patients with acute pulmonary embolism (PE).

Methods: We evaluated 151 consecutive subjects with suspected PE and without cardiopulmonary comorbidities. DE-CTA derived perfused blood volume (PBV) of each pulmonary lobe was measured applying a semi-automated lobar segmentation technique. In patients with PE, blood clot location was assessed, and CT-based vascular obstruction index of each lobe (CTOIlobe) was calculated and classified into three groups: CTOIlobe= 0, low CTOIlobe (1-50%) and high CTOIlobe (>50%).

Results: Among patients without PE (103/151, 68.2%), median lobar PBV was 13.7% (IQR 10.2-18.0%); the right middle lobe presented lower PBV when compared to all the other lobes (p < .001). In patients with PE (48/151, 31.8%), lobar PBV was 12.6% (IQR 9.6-15.7%), 13.7% (IQR 10.1-16.7%) and 6.5% (IQR 5.1-10.2%) in the lobes with CTOIlobe= 0, low CTOIlobe and high CTOIlobe scores, respectively, with a significantly decreased PBV in the lobes with high CTOIlobe score (p < .001). ROC analysis of lobar PBV for prediction of high CTOIlobe score revealed AUC of 0.847 (95%CI 0.785-0.908).

Conclusion: Pulmonary perfusion was heterogeneously distributed along the pulmonary lobes in patients without cardiopulmonary diseases. In patients with PE, the lobes with high vascular obstruction score (CTOIlobe> 50%) presented a decreased lobar perfusion.

Keywords: Blood volume; CTOI, Computed tomography obstruction index; Computed tomography angiography; DE-CTA, Dual-energy computed tomography angiography; Dual-energy computed tomography (DECT); PBV, Perfused blood volume; Pulmonary embolism; Pulmonary perfusion.

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Conflict of interest statement

The authors report no declarations of interest.

Figures

ga1
Graphical abstract
Fig. 1
Fig. 1
52-year-old woman with acute pulmonary embolism. CTA axial image shows a filling defect in the right pulmonary artery (arrow in a). A diffusely reduced iodine density in the right lung (area demarcated by yellow line and represented by blue color) is visualized in the color-coded pulmonary iodine map (b). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 2
Fig. 2
Schematic representation of image postprocessing steps. Following CT acquisition, pulmonary lobes were segmented using Interactive Lobe Segmentation tool from 3D Slicer platform (http://www.slicer.org). A small number of fiducial points (5−10) was manually selected along the right and left oblique fissures and the right horizontal fissure. A label map delimiting each lung lobe was created by the platform, based on the user-specified fiducial points (a). In b, quantitative features of the whole lung and of each lung lobe were obtained (I - lung density histogram, II - lung volume, III – lung mass). Iodine density of each lung lobe (c) was acquired after merging segmented lung label map with iodine map (represented in grayscale). RUL, right upper lobe; RML, right middle lobe; RLL, right lower lobe; LUL, left upper lobe; LLL, left lower lobe.
Fig. 3
Fig. 3
Box and whisker plot with individual data points illustrating the variation of PBV in the lobes of patients with negative PE. Right middle lobe presented a significantly reduced PBV (p < .001). RUL, right upper lobe; RML, right middle lobe; RLL, right lower lobe; LUL, left upper lobe; LLL, left lower lobe.
Fig. 4
Fig. 4
Graph chart illustrating blood clot distribution according to lobar CTOIlobe score. * central and peripheral clots within the same lobe.
Fig. 5
Fig. 5
Box and whisker plot illustrating the PBV in the lobes without vascular obstruction (score = 0), with low CTOIlobe score (1–50%) and high CTOIlobe score (>50%) in the patients with PE.
Fig. 6
Fig. 6
Receiver operating characteristic (ROC) curve of lobar PBV for prediction of high vascular obstruction score (CTOIlobe>50%).
See this image and copyright information in PMC

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