title: Effectiveness of automated quantification of pulmonary perfused blood volume using dual-energy CTPA for the severity assessment of acute pulmonary embolism.
abstract: OBJECTIVE
  The purpose of this study was to determine whether automated quantification of pulmonary perfused blood volume (PBV) in dual-energy computed tomography pulmonary angiography is of diagnostic value in assessing the severity of acute pulmonary embolism (PE).
  
  
  METHODS
  Ethical approval and informed consent were waived by the responsible institutional review board for this retrospective study. Of 224 consecutive patients with dual-energy computed tomography pulmonary angiographic findings positive for acute PE, we excluded 153 patients because of thoracic comorbidities (n = 130), missing data (n = 11), severe artifacts (n = 11), or inadequate enhancement (n = 1). Automated quantification of PBV was performed in the remaining 71 patients (mean [SD] age, 62 [16] years) with acute PE and no cardiopulmonary comorbidities. Perfused blood volume values adjusted for age and sex were correlated with the Qanadli obstruction score, morphological computed tomographic signs of right heart dysfunction, serum levels of troponin, and the necessity for intensive care unit (ICU) admission.
  
  
  RESULTS
  Dual-energy computed tomography pulmonary angiography-derived PBV values inversely correlated with the Qanadli score (r = -0.46; P < 0.001), the right and left ventricle (RV/LV) ratio (r = -0.52; P < 0.001), and troponin I (r = -0.45; P = 0.001). The patients with global PBV values lower than 60% were significantly more likely to require admission to an ICU than did the patients with global pulmonary PBV of 60% or higher (47% vs 11%; P = 0.003; positive predictive value, 47%; negative predictive value, 89%). On the univariate analysis, a significant negative correlation was found between the global PBV values and the Qanadli obstruction score (r = -0.46; P < 0.001), the RV/LV diameter ratio (r = -0.52; P < 0.001), and the necessity for ICU admission (r = -0.39; P = 0.001). On the retrospective multivariate regression analysis, the areas under the receiver operating characteristic curve for the prediction of ICU admission were 0.75 for the pulmonary PBV, 0.83 for the Qanadli obstruction score, 0.68 for the computed tomographic signs of right heart dysfunction (interventricular septal bowing and/or contrast reflux), and 0.76 for the RV/LV diameter ratio.
  
  
  CONCLUSIONS
  Dual-energy computed tomography pulmonary angiography can be used for an immediate, reader-independent estimation of global pulmonary PBV in acute PE, which inversely correlates with thrombus load, laboratory parameters of PE severity, and the necessity for ICU admission.
authors.affiliation: Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 Munich, Germany. felix.meinel@med.uni-muenchen.de
authors.forename: Felix G
authors.initials: FG
authors.lastname: Meinel
authors.forename: Anita
authors.initials: A
authors.lastname: Graef
authors.forename: Fabian
authors.initials: F
authors.lastname: Bamberg
authors.forename: Sven F
authors.initials: SF
authors.lastname: Thieme
authors.forename: Florian
authors.initials: F
authors.lastname: Schwarz
authors.forename: Wieland H
authors.initials: WH
authors.lastname: Sommer
authors.forename: Claus
authors.initials: C
authors.lastname: Neurohr
authors.forename: Christian
authors.initials: C
authors.lastname: Kupatt
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Thorsten R C
authors.initials: TR
authors.lastname: Johnson
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000792:Angiography / Q000706:statistics & numerical data*; D001783:Blood Flow Velocity; D001810:Blood Volume; D001811:Blood Volume Determination / Q000379:methods; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011652:Pulmonary Circulation; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015900:Radiography, Dual-Energy Scanned Projection / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D055815:Young Adult