title: Contrast Circulation Time to Assess Right Ventricular Dysfunction in Pulmonary Embolism: A Retrospective Pilot Study.
abstract: OBJECTIVE
  To optimize enhancement of pulmonary arteries and facilitate diagnosis of pulmonary embolism (PE), modern computed tomography angiography (CTA) contains a contrast bolus tracking system. We explored the diagnostic accuracy of the time-intensity curves given by this automated system to identify right ventricular dysfunction (RVD) in acute PE.
  
  
  METHODS
  114 CTAs with a diagnosis of PE were reviewed. RVD was defined as right-to-left ventricular diameter ratio of 1 or greater. Four parameters on time-intensity curves were identified. Parameters between CTAs with and those without RVD were compared with the Wilcoxon rank-sum test. The ability of the four parameters to discriminate patients with RVD was explored by compiling the area under the operating curves (AUC).
  
  
  RESULTS
  The time needed by the contrast media to reach the pulmonary artery [8 seconds (IQR: 7-9) versus 7 seconds (IQR: 6-8), p<0.01], the time needed to reach 40 Hounsfield units (HU) [11 seconds (IQR: 8.5-14) versus 9.5 seconds (IQR: 8-10.5), p<0.01], and the contrast intensity reached after 10 seconds [19 HU (IQR: 4-67) versus 53 HU (IQR: 32-80), p<0.05] were all statistically different between CTA with and CTA without RVD. Those three parameters changed gradually across severity categories of RVD (p<0.05 for trend). Their AUC to identify RVD ranged from 0.63 to 0.66. The slope of contrast intensity over time was not informative: [31 HU/s (IQR: 20-57) in CTA with, compared to 36 HU/s (IQR: 22.5-53) in CTA without RVD, p = 0.60].
  
  
  CONCLUSIONS
  Several parameters of the time-intensity curve obtained by the bolus tracking system are associated with RVD assessed on CTA images. Of those, the time needed to reach a predefined threshold seems to be the easiest to obtain in any CTA without additional processing time or contrast injection. However, the performance of those parameters is globally low.
authors.affiliation: Department of Internal medicine, Hôpital neuchâtelois, Chasseral 20, 2300 La Chaux-de-Fonds, Switzerland.|Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals (HUG), Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.
authors.forename: Gregor
authors.identifier: http://orcid.org/0000-0002-1548-7339
authors.initials: G
authors.lastname: John
authors.affiliation: Department of radiology, Emergency-room radiology unit, Geneva University Hospitals (HUG), Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Platon
authors.affiliation: Department of radiology, Emergency-room radiology unit, Geneva University Hospitals (HUG), Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.
authors.forename: Pierre-Alexandre
authors.initials: PA
authors.lastname: Poletti
authors.affiliation: Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals (HUG), Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland.|Geneva Faculty of Medicine, Michel-Servet 1, 1206 Geneva, Switzerland.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Perrier
authors.affiliation: Intensive Care Service, Geneva University Hospitals, and Geneva Faculty of Medicine, Gabrielle Perret-Gentil 4, 1211 Geneva, Switzerland.|Geneva Hemodynamic Research Group, Geneva Faculty of Medicine, Michel-Servet 1, 1206 Geneva, Switzerland.
authors.forename: Karim
authors.initials: K
authors.lastname: Bendjelid
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001776:Blood Circulation Time; D000072226:Computed Tomography Angiography; D003287:Contrast Media / Q000008:administration & dosage*; D004452:Echocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D012189:Retrospective Studies; D018497:Ventricular Dysfunction, Right / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology
chemical_list: D003287:Contrast Media