Dual-energy CT based scoring to estimate perfusion changes after balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension

BackgroundBalloon pulmonary angioplasty (BPA) is a treatment option for chronic thromboembolic pulmonary hypertension (CTEPH) patients ineligible for surgery.Evaluation of disease severity and treatment response rely on right heart catheterization (RHC) and clinical evaluation.Lung perfusion is often not considered as evaluation requires techniques beyond the capabilities of computed tomography pulmonary angiography (CTPA).Dual-energy (DECT-PA) provides traditional diagnostic images, and lung perfusion blood volume (PBV) images to obtain perfusion defect (PD) scores.We assessed whether PD score could detect changes in pulmonary perfusion before, during, and after BPA treatment in CTEPH patients. Methods J o u r n a l P r e -p r o o fThis prospective study included patients (n=17) diagnosed with CTEPH and allocated to BPA intervention.Patients underwent DECT-PA during their diagnostic workup, 2-3 weeks after the second treatment, and 3-6 months after the last treatment.Two observers graded the severity of perfusion defects on PBV images, obtaining the PD score.RHC, quantitative perfusion, and clinical parameters were recorded. ResultsPD score improved from baseline (114.7) to second scan (8.13.4,p<0.001), and to followup (7.43.6,p<0.0001).Pulmonary vascular resistance decreased from baseline (8.483.41WU) to follow-up (5.091.73WU, p<0.001).Intra-observer agreement was substantial, but inter-observer agreement was inferior, though the latter improved when observing the changes in PD score.Quantitative perfusion variables trended towards a decrease in perfusion. ConclusionsPerfusion defect score from DECT-PA can estimate changes in pulmonary perfusion before, during, and after BPA interventions.Though intra-observer agreement is substantial, interobserver agreement is variable.