title: CT-based ballistic wound path identification and trajectory analysis in anatomic ballistic phantoms.
abstract: OBJECTIVE
  To evaluate the accuracy of computed tomography (CT)-based ballistic wound path identification in phantoms by determining the agreement between actual shooting angles and both trajectory angles measured with a picture archiving and communication system (PACS) angle tool and angles calculated from x, y, z coordinates of the entrance and exit points.
  
  
  METHODS
  In this institutional review board-approved model study, two simulated legs were shot by a trained marksman from 50 yards at six clinometer-measured angles with a 0.30-06 rifle and then scanned at multidetector CT. Radiologists measured the wound path angles on paracoronal reformations by using a PACS angle tool. Observers determined the Cartesian coordinates of the entrance and exit points of the wound paths on axial CT images by using detailed instructions. Angles were calculated from these coordinates by using a computer arctangent function. Agreement between the angles was evaluated with Bland-Altman plots. Means, ranges, and standard deviations of the angles also were determined.
  
  
  RESULTS
  Radiologists identified all six wound paths on the CT images. The PACS tool-based measured and coordinate-based calculated angles were within 5° of the shooting angles. Results indicated that in larger study populations, one can be 91% confident that future coordinate-based angle calculations will differ from the actual shooting angle by no more than 5° and 95% confident that PACS tool-based angle measurements will differ from the actual shooting angles by no more than 4.5°. One can be 95% confident that future coordinate-based angle calculations will differ from PACS angle measurements by no more than 4.02°.
  
  
  CONCLUSIONS
  Study results demonstrated the feasibility of consistent wound path identification and the accuracy of trajectory angle determination in models with use of multidetector CT.
authors.affiliation: Department of Radiology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA. les.folio@nih.gov
authors.forename: Les R
authors.initials: LR
authors.lastname: Folio
authors.forename: Tatjana V
authors.initials: TV
authors.lastname: Fischer
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Shogan
authors.forename: Michael I
authors.initials: MI
authors.lastname: Frew
authors.forename: Pil S
authors.initials: PS
authors.lastname: Kang
authors.forename: Rolf
authors.initials: R
authors.lastname: Bunger
authors.forename: James M
authors.initials: JM
authors.lastname: Provenzale
mesh_terms: D005240:Feasibility Studies; D006801:Humans; D066298:In Vitro Techniques; D007869:Leg Injuries / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014948:Wounds, Gunshot / Q000000981:diagnostic imaging*