by Bennet Hensen, Susanne Hellms, Christopher Werlein, Danny Jonigk, Phillip Alexander Gronski, Inga Bruesch, Regina Rumpel, Eva-Maria Wittauer, Florian W R Vondran, Dennis L Parker, Frank Wacker, Marcel Gutberlet
Abstract:
Purpose To develop and evaluate susceptibility corrected 2D proton resonance frequency (PRF)-based magnetic resonance (MR)-thermometry for the accurate assessment of the ablation zone of hepatic microwave ablation (MWA). Methods and materials Twelve hepatic MWA were performed in five LEWE minipigs with human-like fissure-free liver. Temperature maps during ablation of PRF-based MR-thermometry were corrected by modeling heat induced susceptibility changes. Ablation zones were determined using cumulative equivalent minutes at 43 °C (CEM43) as tissue damage model. T1 weighted (w) post-ablation contrast-enhanced (CE) MR-imaging and manually segmented postmortem histology were used for validation. The agreement of uncorrected (raw) and susceptibility corrected (corr) MR-thermometry with T1w post-ablation CE MR-imaging and histology was evaluated. The Wilcoxon-signed rank test and Bland-Altman analysis were applied. Results With the susceptibility corrected MR-thermometry a significantly increased dice coefficient (raw: 77\% vs. corr: 83\%, p \textless 0.01) and sensitivity (raw: 72\% vs. corr: 82\%, p \textless 0.01) was found for the comparison to T1w-CE imaging as well as histopathology (dice coefficients: raw: 76\% vs. corr: 79\%, p \textless 0.001; sensitivity: raw: 72\% vs. corr: 74\%, p \textless 0.001). While major axis length was significantly increased (7.1 mm, p \textless 0.001) and minor axis length significantly decreased (2.2 mm, p \textless 0.001) in uncorrected MR-thermometry compared to T1w-CE MR-imaging, no significant bias was found after susceptibility correction. Conclusion Using susceptibility corrected 2D PRF-based MR-thermometry to predict the ablation zones of hepatic MWA provided a good agreement in comparison to T1w post-ablation CE MR-imaging and histopathology.
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Reference:
Correction of heat-induced susceptibility changes in respiratory-triggered 2D-PRF-based thermometry for monitoring of magnetic resonance-guided hepatic microwave ablation in a human-like \textitin vivo porcine model (Bennet Hensen, Susanne Hellms, Christopher Werlein, Danny Jonigk, Phillip Alexander Gronski, Inga Bruesch, Regina Rumpel, Eva-Maria Wittauer, Florian W R Vondran, Dennis L Parker, Frank Wacker, Marcel Gutberlet), In International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group, volume 39, 2022.
Bibtex Entry:
@article{hensen_correction_2022,
	title = {Correction of heat-induced susceptibility changes in respiratory-triggered 2D-{PRF}-based thermometry for monitoring of magnetic resonance-guided hepatic microwave ablation in a human-like \textit{in vivo} porcine model},
	volume = {39},
	issn = {0265-6736},
	url = {http://europepmc.org/abstract/MED/36336401},
	doi = {10.1080/02656736.2022.2138987},
	abstract = {Purpose
To develop and evaluate susceptibility corrected 2D proton resonance frequency (PRF)-based magnetic resonance (MR)-thermometry for the accurate assessment of the ablation zone of hepatic microwave ablation (MWA).
Methods and materials
Twelve hepatic MWA were performed in five LEWE minipigs with human-like fissure-free liver. Temperature maps during ablation of PRF-based MR-thermometry were corrected by modeling heat induced susceptibility changes. Ablation zones were determined using cumulative equivalent minutes at 43 °C (CEM43) as tissue damage model. T1 weighted (w) post-ablation contrast-enhanced (CE) MR-imaging and manually segmented postmortem histology were used for validation. The agreement of uncorrected (raw) and susceptibility corrected (corr) MR-thermometry with T1w post-ablation CE MR-imaging and histology was evaluated. The Wilcoxon-signed rank test and Bland-Altman analysis were applied.
Results
With the susceptibility corrected MR-thermometry a significantly increased dice coefficient (raw: 77\% vs. corr: 83\%, p {\textless} 0.01) and sensitivity (raw: 72\% vs. corr: 82\%, p {\textless} 0.01) was found for the comparison to T1w-CE imaging as well as histopathology (dice coefficients: raw: 76\% vs. corr: 79\%, p {\textless} 0.001; sensitivity: raw: 72\% vs. corr: 74\%, p {\textless} 0.001). While major axis length was significantly increased (7.1 mm, p {\textless} 0.001) and minor axis length significantly decreased (2.2 mm, p {\textless} 0.001) in uncorrected MR-thermometry compared to T1w-CE MR-imaging, no significant bias was found after susceptibility correction.
Conclusion
Using susceptibility corrected 2D PRF-based MR-thermometry to predict the ablation zones of hepatic MWA provided a good agreement in comparison to T1w post-ablation CE MR-imaging and histopathology.},
	language = {eng},
	number = {1},
	journal = {International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group},
	author = {Hensen, Bennet and Hellms, Susanne and Werlein, Christopher and Jonigk, Danny and Gronski, Phillip Alexander and Bruesch, Inga and Rumpel, Regina and Wittauer, Eva-Maria and Vondran, Florian W R and Parker, Dennis L and Wacker, Frank and Gutberlet, Marcel},
	year = {2022},
	pages = {1387--1396}
}