title: [Application of virtual non-enhanced images in evaluating subarachnoid hemorrhage by dual-energy computed tomography angiography].
abstract: OBJECTIVE
  To investigate the feasibility of virtual non-enhanced images in evaluating the spontaneous subarachnoid hemorrhage (SAH) by dual-energy computed tomography angiography.
  
  
  METHODS
  Dual-energy computed tomography angiography was performed in 43 SAH patients.Virtual non-enhanced images were obtained by using Liver VNC software. paired t-test was performed to compare the signal to noise ratio between the conventional plain scan and virtual non-enhanced images. Diagnostic accuracy for SAH by virtual non-enhanced images was calculated by using the conventional plain scan images as a gold standard. Quality score was calculated to evaluate whether virtual non-enhanced images can meet the imaging requirements of SAH.
  
  
  RESULTS
  The signal to noise ratio was 8.63?0.53 among plain scan images and 3.96?0.52 among virtual non-enhanced images ( t=43.18,P=0.000) . The sensitivity, specificity, and accuracy of virtual non-enhanced imaging in diagnosing the SAH were 97.05%, 100%, and 97.67% in per-patient analysis, and were 94.64%, 100%, and 98.97% in per-lesion analysis. The quality scores were 3 in six patients, 2 in 27 patients, and 1 in two patients.
  
  
  CONCLUSIONS
  Virtual non-enhanced images can meet the clinical requirements of diagnosis, although it has more intensive noise than conventional plain scan images. Furthermore, it has higher accuracy in evaluating SAH.
authors.affiliation: Department of Radiology, Changzhi Medical College, Changzhi, Shanxi 046000, China. gxlyr910@sina.com
authors.forename: Xing
authors.initials: X
authors.lastname: Guo
authors.forename: Wei
authors.initials: W
authors.lastname: Ding
authors.forename: Hui-juan
authors.initials: HJ
authors.lastname: Qin
mesh_terms: D000328:Adult; D000368:Aged; D002533:Cerebral Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*