title: Cardiovascular parameters to assess the severity of acute pulmonary embolism with computed tomography.
abstract: BACKGROUND
  Computed tomographic pulmonary angiography (CTPA) has been established as a first-line test in the acute pulmonary embolism (APE) diagnostic algorithm, but the assessment of the severity of APE by this method remains to be explored.
  
  
  OBJECTIVE
  To retrospectively evaluate right ventricular (RV) dysfunction and severity in patients with APE without underlying cardiopulmonary disease using helical computed tomography (CT).
  
  
  METHODS
  Seventy-three patients (35 men and 38 women) were divided into two groups according to the clinical findings: severe APE (n=22) and non-severe APE (n=51). Pulmonary artery CT obstruction index was calculated according to the location and degree of clots in the pulmonary arteries. Cardiovascular parameters including RV short axis and left ventricular (LV) short axis, RV short axis to LV short axis (RV/LV) ratio, main pulmonary artery, azygos vein, and superior vena cava diameters were measured. Leftward bowing of the interventricular septum, reflux of contrast medium into the inferior vena cava and azygos vein, and bronchial artery dilatation were also recorded. The results were analyzed by Mann-Whitney U test, chi(2) test, Spearman's rank correlation coefficient, and the area under the receiver operating characteristic curve (A(z)).
  
  
  RESULTS
  CT obstruction index in patients with severe APE (median 43%) was higher than that of patients with non-severe APE (median 20%). Comparison of cardiovascular parameters between patients with severe and non-severe pulmonary embolism showed significant differences in RV short axis, LV short axis, RV/LV ratio, RV wall thickness, main pulmonary artery diameter, azygos vein diameter, leftward bowing of the interventricular septum, and bronchial artery dilatation. The correlation between CT obstruction indexes and cardiovascular parameters was significant. Spearman's rank correlation coefficient was highest between RV/LV ratio and CT obstruction index. A(z) values were significantly higher than 0.5 for CT obstruction index, LV short axis, RV/LV ratio, main pulmonary artery diameter, and azygos vein diameter.
  
  
  CONCLUSIONS
  These results suggest that CTPA is a practical and accurate means for evaluating RV dysfunction of pulmonary embolism in patients without any underlying cardiopulmonary disease and can discriminate between severe and non-severe APE.
authors.affiliation: Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
authors.forename: Dian-Jiang
authors.initials: DJ
authors.lastname: Zhao
authors.forename: Da-Qing
authors.initials: DQ
authors.lastname: Ma
authors.forename: Wen
authors.initials: W
authors.lastname: He
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.forename: Chun-Shuang
authors.initials: CS
authors.lastname: Guan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D012372:ROC Curve; D012189:Retrospective Studies; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D036542:Tomography, Spiral Computed / Q000379:methods*; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media; D007472:Iohexol