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Validation of fast MR thermometry at 1.5 T with gradient-echo echo planar imaging sequences: phantom and clinical feasibility studies

Cernicanu, Alexandru
Lepetit-Coiffe, Matthieu
Roland, Joerg
Published in NMR in Biomedicine. 2008, vol. 21, no. 8, p. 849-58
Abstract The purpose of this work was to validate in phantom studies and demonstrate the clinical feasibility of MR proton resonance frequency thermometry at 1.5 T with segmented gradient-echo echo planar imaging (GRE-EPI) sequences during liver tumour radiofrequency (RF) ablation. Classical GRE acquisitions and segmented GRE-EPI acquisitions were performed at 1.5 T during simultaneous RF heating with an MR-compatible RF electrode placed in an agar gel phantom. Temperature increments were calculated and compared with four optical temperature probe measurements using Bland- Altman analysis. In a preliminary clinical feasibility study, the rapid GRE-EPI sequence (echo train length = 13) was used for MR temperature monitoring of RF ablation of liver tumours in three patient procedures. For phantom experiments, the Bland-Altman mean of differences between MR and optical probe temperature measurements was <0.4 degrees C, and the 95% limits of agreement value was <1.4 degrees C. For the in vivo studies, respiratory-triggered GRE-EPI acquisitions yielded a temperature accuracy of 1.3 +/- 0.4 degrees C (acquisition time = 0.6 s/image, spatial coverage of three slices/respiratory cycle). MR proton resonance frequency thermometry at 1.5 T yields precise and accurate measurements of temperature increment with both classical GRE and rapid GRE-EPI sequences. Rapid GRE-EPI sequences minimize intra-scan motion effects and can be used for MR thermometry during RF ablation in moving organs.
Keywords Body Temperature/physiologyEcho-Planar Imaging/instrumentation/methodsFeasibility StudiesHumansImage Interpretation, Computer-Assisted/methodsPhantoms, ImagingReproducibility of ResultsSensitivity and SpecificityThermography/instrumentation/methods
Stable URL http://archive-ouverte.unige.ch/unige:1168
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PMID: 18574794
Research group Imagerie et radiologie interventionnelle du foie, des voies biliaires et du pancréas (316)
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