title: Hyperacute thermal lesions: MR imaging evaluation of development in the brain.
abstract: OBJECTIVE
  To determine the natural time course of development of hyperacute thermal lesions in the brain.
  
  
  METHODS
  Ten interstitial lesions were created in five rabbit brains with a radio-frequency probe; an electrode-tip temperature of 80 degrees C was maintained for 60 seconds. Continuous fast spin-echo magnetic resonance (MR) imaging was used to follow lesion development for a minimum of 30 minutes. Temporal variations in lesion size and signal intensity were examined. Findings in final images were correlated with histologic findings.
  
  
  RESULTS
  Images demonstrated a focal hyperintense zone, which developed into an expanding ring of edema surrounding a necrotic center in about 10 minutes. Quantitative analysis revealed a 23% +/- 6 (standard deviation) increase in average signal intensity of the edema layer and a 152% +/- 41 increase in overall lesion size.
  
  
  CONCLUSIONS
  Full development of a thermal lesion is delayed for a period of minutes. Clinical implications of this effect should be considered when MR imaging-guided thermal ablation is performed.
authors.affiliation: Department of Radiological Sciences, University of California Los Angeles School of Medicine 90024-1721, USA.
authors.forename: K
authors.initials: K
authors.lastname: Farahani
authors.forename: P S
authors.initials: PS
authors.lastname: Mischel
authors.forename: K L
authors.initials: KL
authors.lastname: Black
authors.forename: A A
authors.initials: AA
authors.lastname: De Salles
authors.forename: Y
authors.initials: Y
authors.lastname: Anzai
authors.forename: R B
authors.initials: RB
authors.lastname: Lufkin
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology*; D001929:Brain Edema / Q000473:pathology*; D004564:Electrocoagulation; D006358:Hot Temperature; D006979:Hyperthermia, Induced; D008279:Magnetic Resonance Imaging; D011817:Rabbits; D013997:Time Factors