Hyperacute thermal lesions: MR imaging evaluation of development in the brain

Radiology. 1995 Aug;196(2):517-20. doi: 10.1148/radiology.196.2.7617870.


Purpose: To determine the natural time course of development of hyperacute thermal lesions in the brain.

Materials and 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.

Conclusion: 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.

MeSH terms

  • Animals
  • Brain / pathology*
  • Brain Edema / pathology*
  • Electrocoagulation
  • Hot Temperature
  • Hyperthermia, Induced
  • Magnetic Resonance Imaging
  • Rabbits
  • Time Factors