MRI-guided radiofrequency thermal ablation of implanted VX2 liver tumors in a rabbit model: demonstration of feasibility at 0.2 T.
Successful radiofrequency (RF) thermal ablation was performed on VX2 tumors implanted in 23 rabbit livers under magnetic resonance (MR) guidance using a C-arm-shaped low-field 0.2 T system. RF application and immediate postprocedure MRI of all animals was performed [T2-weighted, turbo short tau inversion recovery (STIR), T1-weighted before and after gadopentetate dimeglumine administration). Follow-up MRI with a superparamagnetic iron oxide (SPIO) contrast medium was performed in nine rabbits at 2 weeks and in four rabbits at 1 month post RF ablation. All livers were harvested for pathologic examination. T2-weighted and turbo-STIR images demonstrated the highest tumor-to-RF-thermal lesion contrast-to-noise ratios (CNRs; means 4.5 and 3.8, respectively) on postprocedure images; this was redemonstrated at 2- and 4-week follow-up imaging. T2-weighted imaging never overestimated pathologic lesion size by more than 2 mm, and the radiologic-pathologic correlation coefficient was not less than 0.90. In conclusion, MRI-guided RF thermal ablation in implanted liver tumor is feasible using a C-arm-shaped low-field 0.2 T system. The thermal lesion size can be most accurately monitored with T2-weighted and turbo-STIR images.
Department of Radiology/MRI, University Hospitals of Cleveland/Case Western Reserve University, OH 44106, USA.
E M
EM
Merkle
D T
DT
Boll
T
T
Boaz
J L
JL
Duerk
Y C
YC
Chung
G H
GH
Jacobs
M E
ME
Varnes
J S
JS
Lewin
D000818:Animals; D003287:Contrast Media; D004867:Equipment Design; D019786:Gadolinium DTPA; D006979:Hyperthermia, Induced / Q000295:instrumentation*; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008099:Liver / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000473:pathology / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D009368:Neoplasm Transplantation; D011817:Rabbits
D003287:Contrast Media; D019786:Gadolinium DTPA