title: Differentiation of heroin and cocaine using dual-energy CT-an experimental study.
abstract: OBJECTIVE
  To evaluate if heroin and cocaine can be distinguished using dual-energy CT.
  
  
  METHODS
  Twenty samples of heroin and cocaine at different concentrations and standardized compression (SC) were scanned in dual-energy mode on a newest generation Dual Energy 64-row MDCT scanner. CT number, spectral graphs, and dual-energy index (DEI) were evaluated. Results were prospectively tested on six original samples from a body packer. Wilcoxon's test was used for statistical evaluation.
  
  
  RESULTS
  Values are given as median and range. Under SC, the CT number of cocaine samples (-29.87 Hounsfield unit (HU) [-125.85; 16.16 HU]) was higher than the CT number of heroin samples (-184.37 HU [-199.81; -159.25 HU]; p < 0.01). Slope of spectral curves for cocaine was -2.36 HU/keV [-7.15; -0.67 HU/keV], and for heroin, 1.75 HU/keV [1.28; 2.5 HU/keV] (p < 0.01). DEI was 0.0352 [0.0081; 0.0528] for cocaine and significantly higher than for heroin samples (-0.0127 [-0.0097; -0.0159]; p < 0.001). While CT number was inconclusive, all six original packs were correctly classified after evaluation of the spectral curve and DEI. In contrast to the CT number, slope of the spectral curve and DEI were independent of concentration and compression.
  
  
  CONCLUSIONS
  The slope of the spectral curve and the DEI from dual-energy CT data can be used to distinguish heroin and cocaine in vitro; these results are independent of compression and concentration in the measured range.
authors.affiliation: Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336, Munich, Germany, jochen.grimm@chuv.ch.
authors.forename: Jochen
authors.initials: J
authors.lastname: Grimm
authors.forename: Ramona
authors.initials: R
authors.lastname: Wudy
authors.forename: Edvard
authors.initials: E
authors.lastname: Ziegeler
authors.forename: Stefan
authors.initials: S
authors.lastname: Wirth
authors.forename: Michael
authors.initials: M
authors.lastname: Uhl
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Michael
authors.initials: M
authors.lastname: Scherr
mesh_terms: D003042:Cocaine / Q000737:chemistry*; D003415:Crime; D004340:Drug Contamination; D005547:Foreign Bodies; D003932:Heroin / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007978:Levamisole / Q000737:chemistry; D061330:Multidetector Computed Tomography / Q000379:methods*; D009294:Narcotics / Q000737:chemistry*; D011446:Prospective Studies
chemical_list: D009294:Narcotics; D007978:Levamisole; D003932:Heroin; D003042:Cocaine