Article ID Journal Published Year Pages File Type
748677 Sensors and Actuators A: Physical 2015 11 Pages PDF
Abstract

•Design, fabrication and integration of thin-film disposable micro-coils with ablation catheters for MR-thermometry are described.•Integrated capacitors allow for tuning and matching by means of mechanical trimming.•Improvement in the temperature accuracy and SNR by 1.5–10 times compared to the best locally available array coil was demonstrated in-vitro.•Resolution of 1 mm can be maintained during motion by using short acquisition time sequences.•The temperature noise does not exceed 1 °C during motion.

Thin-film micro-coils are integrated with commercially available ablation catheters, for MR-thermometry during laser interstitial thermal therapies (LITTs). The coils are formed on a flexible polyimide substrate and consist of a two-turn electroplated copper inductor and integrated parallel plate capacitors for tuning and matching. Their performance was assessed during Nd:YAG laser ablations in a static phantom study carried out in a 3 T clinical scanner. Further moving phantom studies were performed to calculate errors due to motion. The temperature accuracy is improved by 1.5–10 times in a radius matching the dimensions of the lesions typically treated. Resolution of 1 mm can be maintained during motion by using short acquisition time sequences while the SNR remains sufficient for accurate MR-thermometry. The temperature error on a moving un-heated phantom under respiratory gating does not exceed 1 °C. This demonstration suggests a possible improvement of the overall control of MR-guided LITTs by local temperature monitoring.

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