Real‐time acoustic dosimetry for focused ultrasound surgery.

2011 ◽  
Vol 129 (4) ◽  
pp. 2405-2405
Author(s):  
Jae Chun Jeon ◽  
Suk Wang Yoon
Keyword(s):  
Real Time ◽  
Focused Ultrasound ◽  
Ultrasound Surgery ◽  
Focused Ultrasound Surgery

scholarly journals Real-time 3D MR Thermometry for Focused Ultrasound Surgery

2018 ◽  
Author(s):  
Craig Meyer ◽  
Kim Butts Pauly ◽  
Max Wintermark
Keyword(s):  
Real Time ◽  
Focused Ultrasound ◽  
Mr Images ◽  
Mr Thermometry ◽  
Ultrasound Surgery ◽  
Temperature Mapping ◽  
Focused Ultrasound Surgery ◽  
Mr Temperature Mapping ◽  
Integral Element ◽  
Temperature Maps

MR temperature mapping is an integral element of MR-guided focused ultrasound surgery (FUS). However, acquisition of the MR images required for calculating a temperature map is time consuming, so that it is not possible using conventional nonaccelerated MR techniques to acquire and reconstruct a 3D temperature map in realtime. In this study, we will use spiral k-space scanning and a new accelerated MR technique that we have developed to acquire, reconstruct, and display 3D temperature maps in real time. A new real-time method for 3D MR thermometry would have a major impact on the safety, efficacy, and procedural efficiency of FUS.

Transcranial magnetic resonance–guided focused ultrasound surgery for trigeminal neuralgia: a cadaveric and laboratory feasibility study

2013 ◽  
Vol 118 (2) ◽  
pp. 319-328 ◽  
Author(s):  
Stephen J. Monteith ◽  
Ricky Medel ◽  
Neal F. Kassell ◽  
Max Wintermark ◽  
Matthew Eames ◽  
...  
Keyword(s):  
Skull Base ◽  
Real Time ◽  
Trigeminal Nerve ◽  
Temperature Increase ◽  
Focused Ultrasound ◽  
Mr Thermometry ◽  
Ultrasound Surgery ◽  
Focused Ultrasound Surgery ◽  
Trigeminal Nerves ◽  
Internal Acoustic Canal

Object Transcranial MR-guided focused ultrasound surgery (MRgFUS) is evolving as a treatment modality in neurosurgery. Until now, the trigeminal nerve was believed to be beyond the treatment envelope of existing high-frequency transcranial MRgFUS systems. In this study, the authors explore the feasibility of targeting the trigeminal nerve in a cadaveric model with temperature assessments using computer simulations and an in vitro skull phantom model fitted with thermocouples. Methods Six trigeminal nerves from 4 unpreserved cadavers were targeted in the first experiment. Preprocedural CT scanning of the head was performed to allow for a skull correction algorithm. Three-Tesla, volumetric, FIESTA MRI sequences were performed to delineate the trigeminal nerve and any vascular structures of the cisternal segment. The cadaver was positioned in a focused ultrasound transducer (650-kHz system, ExAblate Neuro, InSightec) so that the focus of the transducer was centered at the proximal trigeminal nerve, allowing for targeting of the root entry zone (REZ) and the cisternal segment. Real-time, 2D thermometry was performed during the 10- to 30-second sonication procedures. Post hoc MR thermometry was performed on a computer workstation at the conclusion of the procedure to analyze temperature effects at neuroanatomical areas of interest. Finally, the region of the trigeminal nerve was targeted in a gel phantom encased within a human cranium, and temperature changes in regions of interest in the skull base were measured using thermocouples. Results The trigeminal nerves were clearly identified in all cadavers for accurate targeting. Sequential sonications of 25–1500 W for 10–30 seconds were successfully performed along the length of the trigeminal nerve starting at the REZ. Real-time MR thermometry confirmed the temperature increase as a narrow focus of heating by a mean of 10°C. Postprocedural thermometry calculations and thermocouple experiments in a phantom skull were performed and confirmed minimal heating of adjacent structures including the skull base, cranial nerves, and cerebral vessels. For targeting, inclusion of no-pass regions through the petrous bone decreased collateral heating in the internal acoustic canal from 16.7°C without blocking to 5.7°C with blocking. Temperature at the REZ target decreased by 3.7°C with blocking. Similarly, for midcisternal targeting, collateral heating at the internal acoustic canal was improved from a 16.3°C increase to a 4.9°C increase. Blocking decreased the target temperature increase by 4.4°C for the same power settings. Conclusions This study demonstrates focal heating of up to 18°C in a cadaveric trigeminal nerve at the REZ and along the cisternal segment with transcranial MRgFUS. Significant heating of the skull base and surrounding neural structures did not occur with implementation of no-pass regions. However, in vivo studies are necessary to confirm the safety and efficacy of this potentially new, noninvasive treatment.

Focused Ultrasound Surgery in Gynecology

2021 ◽  
Author(s):  
Felix Wong ◽  
Lian Zhang ◽  
Zhibiao Wang
Keyword(s):  
Focused Ultrasound ◽  
Ultrasound Surgery ◽  
Focused Ultrasound Surgery
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