title: Material differentiation in forensic radiology with single-source dual-energy computed tomography.
abstract: The goal of this study was to investigate the use of dual-energy computed tomography (CT) in differentiating frequently encountered foreign material on CT images using a standard single-source CT scanner. We scanned 20 different, forensically relevant materials at two X-Ray energy levels (80 and 130 kVp) on CT. CT values were measured in each object at both energy levels. Intraclass correlation coefficient (ICC) was used to determine intra-reader reliability. Analysis of variance (ANOVA) was performed to assess significance levels between X-Ray attenuation at 80 and 130 kVp. T test was used to investigate significance levels between mean HU values of individual object pairings at single energy levels of 80 and 130 kVp, respectively. ANOVA revealed that the difference in attenuation between beam energies of 80 kVp compared to 130 kVp was statistically significant (p < 0.005) for all materials except brass and lead. ICC was excellent at 80 kVp (0.999, p < 0.001) and at 130 kVp (0.998, p < 0.001). T test showed that using single energy levels of 80 and 130 kVp respectively 181/190 objects pairs could be differentiated from one another based on HU measurements. Using the combined information from both energy levels, 189/190 object pairs could be differentiated. Scanning with different energy levels is a simple way to apply dual-energy technique on a regular single-energy CT and improves the ability to differentiate foreign bodies with CT, based on their attenuation values.
authors.affiliation: Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, 8057, Zurich, Switzerland. thomas.ruder@irm.uzh.ch
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Ruder
authors.forename: Yannick
authors.initials: Y
authors.lastname: Thali
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Bolliger
authors.forename: Sandra
authors.initials: S
authors.lastname: Somaini-Mathier
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Thali
authors.forename: Gary M
authors.initials: GM
authors.lastname: Hatch
authors.forename: Sebastian T
authors.initials: ST
authors.lastname: Schindera
mesh_terms: D005547:Foreign Bodies / Q000000981:diagnostic imaging*; D005554:Forensic Medicine / Q000295:instrumentation / Q000379:methods*; D015588:Observer Variation; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000295:instrumentation