Prediction of treatable occluded branches before balloon pulmonary angioplasty using CT imaging in patients with chronic thromboembolic pulmonary hypertension

Background The accurate assessment of the anatomical information of occluded pulmonary arteries (PA) prior to balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) has not been well established. Purpose This study aimed to investigate whether attenuation-modified PA image derived from contrast-enhanced chest computed tomography (CT) could predict treatable occluded branches before BPA in patients with CTEPH. Materials and methods We analyzed 18 consecutive patients (64 ± 16 years) diagnosed with CTEPH. All patients underwent contrast-enhanced chest-CT and lung perfusion single-photon emission computed tomography (SPECT) before BPA. Attenuation-modified PA image was created from contrast-enhanced chest-CT by adjusting the attenuation values of the PA with dedicated software to visualize the entire PA vessels (red branches in Figure A). Occluded branches were defined as non-overlapping areas between attenuate-modified PA and contrast-enhanced images (green branches in Figure B). The occluded branches identified on CT images (red branches in Figure C-1, 2) were validated for concordance with lung perfusion SPECT and angiography. Results A total of 123 obstructed branches were identified on CT images. Concordance was observed in 110 (89.4%) with lung perfusion SPECT and in 95 (77.2%) with angiography. Of these, 94 (76.4%) were treated with BPA. Conclusion This study demonstrated that contrast-enhanced chest-CT with dedicated software is useful for confirming treatable occluded branches before BPA in CTEPH.