title: Added value of lung perfused blood volume images using dual-energy CT for assessment of acute pulmonary embolism.
abstract: OBJECTIVE
  To investigate the added value of lung perfused blood volume (LPBV) using dual-energy CT for the evaluation of intrapulmonary clot (IPC) in patients suspected of having acute pulmonary embolism (PE).
  
  
  METHODS
  Institutional review board approval was obtained for this retrospective study. Eighty-three patients suspected of having PE who underwent CT pulmonary angiography (CTPA) using a dual-energy technique were enrolled in this study. Two radiologists who were blinded retrospectively and independently reviewed CTPA images alone and the combined images with color-coded LPBV over a 4-week interval, and two separate sessions were performed with a one-month interval. Inter- and intraobserver variability and diagnostic accuracy were evaluated for each reviewer with receiver operating characteristic (ROC) curve analysis.
  
  
  RESULTS
  Values for inter- and intraobserver agreement, respectively, were better for CTPA combined with LPBV (ICC=0.847 and 0.937) than CTPA alone (ICC=0.748 and 0.861). For both readers, diagnostic accuracy (area under the ROC curve [Az]) were also superior, when CTPA alone (Az=0.888 [reader 1] and 0.912 [reader 2]) was compared with that after the combination with LPBV images (Az=0.966 [reader 1] and 0.959 [reader 2]) (p<0.001). However, Az values of both images might not have significant difference in statistics, because Az value of CTPA alone was high and 95% confidence intervals overlapped in both images.
  
  
  CONCLUSIONS
  Addition of dual-energy perfusion CT to CTPA improves detection of peripheral IPCs with better interobserver agreement.
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan. Electronic address: radokada@yamaguchi-u.ac.jp.
authors.forename: Munemasa
authors.initials: M
authors.lastname: Okada
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Kunihiro
authors.affiliation: Department of Radiology, Yamaguchi Grand Medical Center, Oosaki 77, Hofu, Yamaguchi 747-8511, Japan.
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Nakashima
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Nomura
authors.affiliation: Department of Radiology, Yamaguchi University Hospital, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Kudomi
authors.affiliation: Department of Radiology, Yamaguchi University Hospital, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
authors.forename: Teppei
authors.initials: T
authors.lastname: Yonezawa
authors.affiliation: Department of Radiology, St. Hills Hospital, Imamurakita 3-7-18, Ube, Yamaguchi 755-0155, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Suga
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Matsunaga
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods; D001810:Blood Volume; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D055420:Perfusion Imaging / Q000379:methods; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Added value; CT pulmonary angiography; Dual-energy CT; Lung perfused blood volume; Pulmonary embolism