title: Use of dual-energy CT and virtual non-calcium techniques to evaluate post-traumatic bone bruises in knees in the subacute setting.
abstract: OBJECTIVE
  The purpose of this study was to determine the ability of dual-energy computed tomography (DECT) and virtual non-calcium (VNCa) imaging to detect magnetic resonance imaging (MRI)-demonstrated bone bruises several weeks after unilateral knee injury.
  
  
  METHODS
  Patients with unilateral knee injury and MRI-confirmed bone bruises who had undergone a DECT scan of both knees were retrospectively identified. Two radiologists evaluated VNCa images for bruises in four regions per knee without knowing the MRI results. The mean CT numbers were calculated for the lesion-positive and lesion-negative regions of the injured knee, and the contralateral knee.
  
  
  RESULTS
  Fourteen patients with a total of 36 regions positive for bone bruises on MRI were identified. The median delay between injury and DECT was 37 days (range, 11-99 days). The mean CT numbers in VNCa images for lesion-positive and lesion-negative regions were -7.6 ± 24.9 HU and -58.2 ± 19.5 HU, respectively. There were no significant differences in mean CT number between the lesion-negative regions in the injured knee and the contralateral knee. No resolution of bruising was seen before week 5, and bone bruising was still identifiable in one out of the two patients scanned at 10 weeks following injury.
  
  
  CONCLUSIONS
  DECT and VNCa images can identify bone bruising for at least 10 weeks after injury.
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
authors.forename: Songtao
authors.initials: S
authors.lastname: Ai
authors.forename: Mingliang
authors.initials: M
authors.lastname: Qu
authors.forename: Katrina N
authors.initials: KN
authors.lastname: Glazebrook
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Peter C
authors.initials: PC
authors.lastname: Rhee
authors.forename: Shuai
authors.initials: S
authors.lastname: Leng
authors.forename: Cynthia H
authors.initials: CH
authors.lastname: McCollough
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000465:Algorithms; D003288:Contusions / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D050815:Fractures, Compression / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007718:Knee Injuries / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014584:User-Computer Interface; D055815:Young Adult