In recent years trans-cranial Magnetic Resonance-guided Focused Ultrasound Surgery (tcMRgFUS) treatments have been performed only using 3T units. Since following some internal analysis, planning images obtained using a 1.5T MRI’s body RF coil (as usually done with 3T systems) showed generally reasonable quality in terms of anatomy visualization and SNR but thermal images noise was above acceptable standard for treatments, a dedicated 2-channels coil was developed to ensure an adequate signal-to-noise ratio (SNR). The SNR is one of the most commonly used parameters to obtain...

The focused ultrasound equipment (ExAblate 4000, InSightec Ltd. - Haifa, Israel) installed in our Department integrates with an MRI unit operating at 1.5T (Signa HDxt, GE Medical System - Milwaukee, Wisconsin, USA) and consists of a hemispheric 1024-element phased-array transducer operating at 650 kHz as those used with 3T MRI units. The use of 3T MRI scanners allows the use of the MR systems body RF coil for treatment planning and real-time thermal monitoring with reasonable compromises in terms of signal to noise ratio (SNR)...

Compared to that achieved using MRI’s body RF coil, the dedicated flexible coil resulted in larger values of the SNR. In particular we measured for the axial plane a SNR equal to 25.8 using dedicated coil whereas it was equal to 4.1 with RF coil: therefore an increase of more than 6 time was achieved with this preliminary analysis.

Even though the SNR linearly increases with magnetic field strength, it should be underlined that on a 1.5T scanner the use of a dedicated coil enabled us to obtain images with a SNR roughly 2.5 times larger than those acquired on 3T scanners using MRI’s body RF coil. This resulted in a safe and precise imaging guidance during tcMRgFUS treatments performed for the first time using a 1.5T unit.

Cesare Gagliardo1, Alessandro Napoli2, Laura Geraci1, Giorgio Collura3, Maurizio Marrale3, Tommaso Vincenzo Bartolotta1, Carlo Catalano2, Massimo Midiri1, Roberto Lagalla1. 1. Section of Radiological Sciences, Department of Biopathology and Medical Biotechnologies, University of Palermo, Palermo, Italy. 2. Radiology Section, Department of Radiological, Oncological and Anatomopathological Sciences, "Sapienza" University of Rome, Rome, Italy. 3. Department of Physics and Chemistry, University of Palermo, Palermo, Italy Corresponding author: Dr Cesare Gagliardo Address: Sezione di Scienze Radiologiche Dipartimento di Biopatologia e Biotecnologie Mediche Università degli Studi di Palermo Via del...

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