title: Quantitative lung perfused blood volume imaging on dual-energy CT: capability for quantitative assessment of disease severity in patients with acute pulmonary thromboembolism.
abstract: BACKGROUND
  Regional iodine distribution assessment on dual-energy computed tomography (DECT) has been suggested as useful for management of acute pulmonary thromboembolism (APTE) patients. However, no reported studies have made a direct comparison between quantitatively assessed DECT and right-to-left ventricular (RV/LV) ratio on CT for differentiation of right heart dysfunction (RHD) from non-right heart dysfunction (NRHD) in APTE patients.
  
  
  OBJECTIVE
  To determine the capability of DECT for differentiation of RHD from NRHD in APTE patients.
  
  
  METHODS
  Thirteen APTE patients underwent DECT and echocardiography at onset of APTE. Patients were divided into RHD (n = 7) and NRHD (n = 6) groups based on echocardiography. A normalized lung perfused blood volume map was generated, and two kinds of overall perfusion (OP) index were determined, one placed over each lung field (OP index A) and as the average from six regions of interest (ROIs) placed over each lung field (OP index B). The heterogeneity index was also determined as the standard deviation for the six ROIs. RV/LV ratio evaluations were also performed. To assess differences between the two groups, each index was statistically compared with the Mann-Whitney U test. The receiver-operating curve-based positive test was then performed to determine the feasible threshold value for dividing patients into the two groups. Finally, differentiation capabilities of the indexes were compared using McNemar's test.
  
  
  RESULTS
  Significant differences between the two groups were found for both OP indexes and RV/LV ratio (P < 0.05). For each of the feasible threshold values, accuracy of each OP index with and without RV/LV ratio was better than that of the RV/LV ratio.
  
  
  CONCLUSIONS
  Quantitative DECT has good potential for differentiation of APTE patients with and without right heart dysfunction.
authors.affiliation: Department of Radiology, Nara Medical University, Kashihara, Nara, Japan sachimiu@naramed-u.ac.jp.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Miura
authors.affiliation: Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.affiliation: Second Department of Internal Medicine, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kimura
authors.affiliation: Department of Radiology, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Kichikawa
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001810:Blood Volume; D003287:Contrast Media; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D007479:Iopamidol; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D012372:ROC Curve; D011856:Radiographic Image Enhancement / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*; D018497:Ventricular Dysfunction, Right / Q000150:complications / Q000000981:diagnostic imaging
chemical_list: D003287:Contrast Media; D007479:Iopamidol
keywords: CT; Lung; dual-energy CT; perfusion; pulmonary thromboembolism