title: Comparison of C-arm Computed Tomography and Digital Subtraction Angiography in Patients with Chronic Thromboembolic Pulmonary Hypertension.
abstract: OBJECTIVE
  To assess the feasibility and diagnostic performance of contrast-enhanced, C-arm computed tomography (CACT) of the pulmonary arteries compared to digital subtraction angiography (DSA) in patients suffering from chronic thromboembolic pulmonary hypertension (CTEPH).
  
  
  METHODS
  Fifty-two patients with CTEPH underwent ECG-gated DSA and contrast-enhanced CACT. Two readers (R1, R2) independently evaluated pulmonary artery segments and their sub-segmental branching using DSA and CACT for optimal image quality. Afterwards, the diagnostic findings, i.e., intraluminal filling defects, stenosis, and occlusion, were compared. Inter-modality and inter-observer agreement was calculated, and subsequently consensus reading was done and correlated to a reference standard representing the overall consensus of both modalities. Fisher's exact test and Cohen's Kappa were applied.
  
  
  RESULTS
  A total of 1352 pulmonary segments were evaluated, of which 1255 (92.8 %) on DSA and 1256 (92.9 %) on CACT were rated to be fully diagnostic. The main causes of the non-diagnostic image quality were motion artifacts on CACT (R1:37, R2:78) and insufficient contrast enhancement on DSA (R1:59, R2:38). Inter-observer agreement was good for DSA (κ = 0.74) and CACT (κ = 0.75), while inter-modality agreement was moderate (R1: κ = 0.46, R2: κ = 0.47). Compared to the reference standard, the inter-modality agreement for CACT was excellent (κ = 0.96), whereas it was inferior for DSA (κ = 0.61) due to the higher number of abnormal consensus findings read as normal on DSA.
  
  
  CONCLUSIONS
  CACT of the pulmonary arteries is feasible and provides additional information to DSA. CACT has the potential to improve the diagnostic work-up of patients with CTEPH and may be particularly useful prior to surgical or interventional treatment.
authors.affiliation: Department for Diagnostic and Interventional Radiology, German Center for Lung Research (DZL), Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. hinrichs.jan@mh-hannover.de.
authors.forename: Jan B
authors.initials: JB
authors.lastname: Hinrichs
authors.affiliation: Department for Diagnostic and Interventional Radiology, German Center for Lung Research (DZL), Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. marquardt.steffen@mh-hannover.de.
authors.forename: Steffen
authors.initials: S
authors.lastname: Marquardt
authors.affiliation: Department for Diagnostic and Interventional Radiology, German Center for Lung Research (DZL), Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. falck.christian.von@mh-hannover.de.
authors.forename: Christian
authors.initials: C
authors.lastname: von Falck
authors.affiliation: Clinic for Pneumology, German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany. hoeper.marius@mh-hannover.de.
authors.forename: Marius M
authors.initials: MM
authors.lastname: Hoeper
authors.affiliation: Clinic for Pneumology, German Center for Lung Research (DZL), Hannover Medical School, Hannover, Germany. olsson.karen@mh-hannover.de.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Olsson
authors.affiliation: Department for Diagnostic and Interventional Radiology, German Center for Lung Research (DZL), Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. wacker.frank@mh-hannover.de.
authors.forename: Frank K
authors.initials: FK
authors.lastname: Wacker
authors.affiliation: Department for Diagnostic and Interventional Radiology, German Center for Lung Research (DZL), Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. meyer.bernhard@mh-hannover.de.
authors.forename: Bernhard C
authors.initials: BC
authors.lastname: Meyer
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction / Q000379:methods*; D002908:Chronic Disease; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000150:complications / Q000000981:diagnostic imaging*; D011856:Radiographic Image Enhancement; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Balloon pulmonary angioplasty; C-arm computed tomography; Chronic thromboembolic pulmonary hypertension; Cone beam CT