title: The influence of body temperature on image contrast in post mortem MRI.
abstract: OBJECTIVE
  To assess the temperature dependency of tissue contrast on post mortem magnetic resonance (PMMR) images both objectively and subjectively; and to visually demonstrate the changes of image contrast at various temperatures.
  
  
  METHODS
  The study was approved by the responsible justice department and the ethics committee. The contrast of water, fat, and muscle was measured using regions of interest (ROI) in the orbit of 41 human corpses to assess how body temperature (range 2.1-39.8 °C) relates to image contrast of T1-weighted (T1W) and T2-weighted (T2W) sequences on PMMR. Regressions were calculated using the method of least squares. Three readers judged visible changes of image contrast subjectively by consensus.
  
  
  RESULTS
  There was a positive relationship between temperature and contrast on T1-weighted (T1W) images and between temperature and the contrast of fat/muscle on T2-weighted (T2W) images. There was a negative relationship between temperature and the contrast of water/fat and water/muscle on T2W images. Subjectively, the influence of temperature became visible below 20 °C on T2W images, and below 10 °C on T1W images.
  
  
  CONCLUSIONS
  Image contrast on PMMR depends on the temperature of a corpse. Radiologists involved in post mortem imaging must be aware of temperature-related changes in MR image contrast. To preserve technical quality, scanning corpses below 10 °C should be avoided.
authors: Center for Forensic Imaging and Virtopsy, Institute of Forensic Medicine, University of Bern, Buehlstrasse 20, CH-3012 Bern, Switzerland. thomas.ruder@irm.unibe.ch
authors: Thomas D
authors: TD
authors: Ruder
authors: Gary M
authors: GM
authors: Hatch
authors: Lea
authors: L
authors: Siegenthaler
authors: Garyfalia
authors: G
authors: Ampanozi
authors: Sandra
authors: S
authors: Mathier
authors: Michael J
authors: MJ
authors: Thali
authors: Oliver M
authors: OM
authors: Weber
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001831:Body Temperature; D002102:Cadaver; D002648:Child; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011180:Postmortem Changes; D051598:Whole Body Imaging