TY - JOUR
T1 - Radiofrequency ablation lesion detection using MR-based electrical conductivity imaging
T2 - A feasibility study of ex vivo liver experiments
AU - Chauhan, Munish
AU - Jeong, Woo Chul
AU - Kim, Hyung Joong
AU - Kwon, Oh In
AU - Woo, Eung Je
N1 - Funding Information:
This work received financial support from the National Research Foundation of Korea (NRF) grant funded by Korea government (MSIP and MEST), grant no. 2010-0018275, 2013R1A2A2A04016066, 2012R1A1A2008477. The authors alone are responsible for the content and writing of the paper.
PY - 2013
Y1 - 2013
N2 - Purpose: The aim of this study was to show the potential of magnetic resonance electrical impedance tomography (MREIT) conductivity imaging in terms of its capability to detect ablated lesions and differentiate tissue conditions in liver radiofrequency (RF) ablation. Materials and methods: RF ablation procedures were performed in bovine livers using a LeVeen RF needle electrode. Ablation lesions were created using a power-controlled mode at 30, 50, and 70W for 1, 3, and 5 min of exposure time, respectively. After the ablation, the liver was cut into several blocks including the ablated lesion, and positioned inside a phantom filled with agarose gel. Electrodes were attached on the side of the phantom and it was placed inside the MRI bore. For MREIT imaging, multi-spin-echo pulse sequence was used to obtain the magnetic flux density data according to the injection currents. Results: The conductivity of ablation lesions was significantly changed with the increase of exposure time (pKW<0.01, Kruskal-Wallis test). With RF powers of 30 and 50 W, significant differences between the coagulation necrosis and hyperaemic rim were observed for more than 5 min and 3 min, respectively (pMW<0.01, Mann-Whitney test). At 70 W, all cases showed significant differences except 3 min (pMW<0.01). The positive correlation between the exposure time and tissue conductivity was observed in both two ablation areas (pSC<0.01, Spearman correlation). Conclusions: This ex vivo feasibility study demonstrates that current MREIT conductivity imaging can detect liver RF ablation lesions without using any contrast media or additional MR scan.
AB - Purpose: The aim of this study was to show the potential of magnetic resonance electrical impedance tomography (MREIT) conductivity imaging in terms of its capability to detect ablated lesions and differentiate tissue conditions in liver radiofrequency (RF) ablation. Materials and methods: RF ablation procedures were performed in bovine livers using a LeVeen RF needle electrode. Ablation lesions were created using a power-controlled mode at 30, 50, and 70W for 1, 3, and 5 min of exposure time, respectively. After the ablation, the liver was cut into several blocks including the ablated lesion, and positioned inside a phantom filled with agarose gel. Electrodes were attached on the side of the phantom and it was placed inside the MRI bore. For MREIT imaging, multi-spin-echo pulse sequence was used to obtain the magnetic flux density data according to the injection currents. Results: The conductivity of ablation lesions was significantly changed with the increase of exposure time (pKW<0.01, Kruskal-Wallis test). With RF powers of 30 and 50 W, significant differences between the coagulation necrosis and hyperaemic rim were observed for more than 5 min and 3 min, respectively (pMW<0.01, Mann-Whitney test). At 70 W, all cases showed significant differences except 3 min (pMW<0.01). The positive correlation between the exposure time and tissue conductivity was observed in both two ablation areas (pSC<0.01, Spearman correlation). Conclusions: This ex vivo feasibility study demonstrates that current MREIT conductivity imaging can detect liver RF ablation lesions without using any contrast media or additional MR scan.
KW - Coagulation necrosis
KW - MREIT
KW - conductivity image
KW - hyperaemic rim
KW - radiofrequency ablation
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U2 - 10.3109/02656736.2013.842265
DO - 10.3109/02656736.2013.842265
M3 - Article
C2 - 24102394
AN - SCOPUS:84885450144
SN - 0265-6736
VL - 29
SP - 643
EP - 652
JO - International Journal of Hyperthermia
JF - International Journal of Hyperthermia
IS - 7
ER -