title: Comparison of contrast in brightness mode and strain ultrasonography of glial brain tumours.
abstract: BACKGROUND
  Image contrast between normal tissue and brain tumours may sometimes appear to be low in intraoperative ultrasound. Ultrasound imaging of strain is an image modality that has been recently explored for intraoperative imaging of the brain. This study aims to investigate differences in image contrast between ultrasound brightness mode (B-mode) images and ultrasound strain magnitude images of brain tumours.
  
  
  METHODS
  Ultrasound radiofrequency (RF) data was acquired during surgery in 15 patients with glial tumours. The data were subsequently processed to provide strain magnitude images. The contrast in the B-mode images and the strain images was determined in assumed normal brain tissue and tumour tissue at selected regions of interest (ROI). Three measurements of contrast were done in the ultrasound data for each patient. The B-mode and strain contrasts measurements were compared using the paired samples t- test.
  
  
  RESULTS
  The statistical analysis of a total of 45 measurements shows that the contrasts in the strain magnitude images are significantly higher than in the conventional ultrasound B-mode images (P < 0.0001).
  
  
  CONCLUSIONS
  The results indicate that ultrasound strain imaging provides better discrimination between normal brain tissue and glial tumour tissue than conventional ultrasound B-mode imaging. Ultrasound imaging of tissue strain therefore holds the potential of becoming a valuable adjunct to conventional intraoperative ultrasound imaging in brain tumour surgery.
authors.affiliation: Department of Medical Technology, SINTEF, Trondheim, Norway. tormod.selbekk@sintef.no
authors.forename: Tormod
authors.initials: T
authors.lastname: Selbekk
authors.forename: Reidar
authors.initials: R
authors.lastname: Brekken
authors.forename: Marit
authors.initials: M
authors.lastname: Indergaard
authors.forename: Ole
authors.initials: O
authors.lastname: Solheim
authors.forename: Geirmund
authors.initials: G
authors.lastname: Unsgård
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity