title: Pulmonary vascular morphology as an imaging biomarker in chronic thromboembolic pulmonary hypertension.
abstract: Patients with chronic thromboembolic pulmonary hypertension (CTEPH) have morphologic changes to the pulmonary vasculature. These include pruning of the distal vessels, dilation of the proximal vessels, and increased vascular tortuosity. Advances in image processing and computer vision enable objective detection and quantification of these processes in clinically acquired computed tomographic (CT) scans. Three-dimensional reconstructions of the pulmonary vasculature were created from the CT angiograms of 18 patients with CTEPH diagnosed using imaging and hemodynamics as well as 15 control patients referred to our Dyspnea Clinic and found to have no evidence of pulmonary vascular disease. Compared to controls, CTEPH patients exhibited greater pruning of the distal vasculature (median density of small-vessel volume: 2.7 [interquartile range (IQR): 2.5-3.0] vs. 3.2 [3.0-3.8]; P = 0.008), greater dilation of proximal arteries (median fraction of blood in large arteries: 0.35 [IQR: 0.30-0.41] vs. 0.23 [0.21-0.31]; P = 0.0005), and increased tortuosity in the pulmonary arterial tree (median: 4.92% [IQR: 4.85%-5.21%] vs. 4.63% [4.39%-4.92%]; P = 0.004). CTEPH was not associated with dilation of proximal veins or increased tortuosity in the venous system. Distal pruning of the vasculature was correlated with the cardiac index (R = 0.51, P = 0.04). Quantitative models derived from CT scans can be used to measure changes in vascular morphology previously described subjectively in CTEPH. These measurements are also correlated with invasive metrics of pulmonary hemodynamics, suggesting that they may be used to assess disease severity. Further work in a larger cohort may enable the use of such measures as a biomarker for diagnostic, phenotyping, and prognostic purposes.
authors.affiliation: Pulmonary and Critical Care Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: F N
authors.initials: FN
authors.lastname: Rahaghi
authors.affiliation: Department of Radiology, Harvard School of Medicine, Boston, Massachusetts, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Ross
authors.affiliation: Pulmonary and Critical Care Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: M
authors.initials: M
authors.lastname: Agarwal
authors.affiliation: Department of Radiology, Harvard School of Medicine, Boston, Massachusetts, USA.
authors.forename: G
authors.initials: G
authors.lastname: González
authors.affiliation: Pulmonary and Critical Care Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Come
authors.affiliation: Pulmonary and Critical Care Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Diaz
authors.affiliation: Department of Radiology, Harvard School of Medicine, Boston, Massachusetts, USA.
authors.forename: G
authors.initials: G
authors.lastname: Vegas-Sánchez-Ferrero
authors.affiliation: Department of Radiology, Harvard School of Medicine, Boston, Massachusetts, USA.
authors.forename: A
authors.initials: A
authors.lastname: Hunsaker
authors.affiliation: Department of Radiology, Harvard School of Medicine, Boston, Massachusetts, USA.
authors.forename: R
authors.initials: R
authors.lastname: San José Estépar
authors.affiliation: Pulmonary and Critical Care Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: A B
authors.initials: AB
authors.lastname: Waxman
authors.affiliation: Pulmonary and Critical Care Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: G R
authors.initials: GR
authors.lastname: Washko
keywords: arterial; chronic thromboembolic pulmonary hypertension; computed tomography; tortuosity