Study of laser ablation in the in vivo rabbit brain with MR thermometry.
OBJECTIVE
To investigate the peak temperature and thermal dose (T(43)) as tissue damage indicators for thermal therapy.


METHODS
The proton resonant frequency (PRF) shift thermal coefficient was calibrated on six in vivo rabbit brains during interstitial laser ablation. The peak temperature and T(43) were correlated with the lesion boundary observed on T2-weighted spin-echo (SE) MRI at 4 hours post-heating in seven thermal lesions using direct MR measurement and analysis based on a binary discriminate model.


RESULTS
The peak temperature and T(43) were 48.3 +/- 1.7 degrees C and 191 +/- 219 minutes, respectively, from the direct MR measurement. The values derived by the binary discriminate analysis were 47.8 +/- 2.2 degrees C and 28 +/- 41 minutes, respectively.


CONCLUSIONS
Our results suggest that tissue damage in rabbit brain 4 hours after thermal ablation can be predicted reliably from a threshold temperature of approximately 48 degrees C.
Department of Radiology, Stanford University, Stanford, California 94305-5488, USA.
Lili
L
Chen
Janaka P
JP
Wansapura
Gary
G
Heit
Kim
K
Butts
D000818:Animals; D001831:Body Temperature / Q000502:physiology*; D001921:Brain / Q000473:pathology; D006979:Hyperthermia, Induced / Q000379:methods*; D017075:Laser Coagulation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011817:Rabbits