TRADITIONAL POSTER - ismrm

Poster Sessions
1811. MR-Guided Unfocused Ultrasound Disruption of the Rat Blood-Brain Barrier
Kelly Ann Townsend 1 , Randy L. King 1 , Greg Zaharchuk 2 , Kim Butts Pauly 1,2
1 Bioengineering, Stanford University, Stanford, CA, United States; 2 Radiology, Stanford University, Stanford, CA, United States
The purpose of this study was to investigate the effects of unfocused ultrasound on blood-brain barrier opening across the whole brain using contract
enhanced-MRI. T1-weighted FSE images of the brain were acquired in rats for several minutes after gadolinium administration and unfocused ultrasound
whole brain treatment. Signal increased immediately after sonication, and continued to increase in the brain as time passed, while muscle signal decreased
due to washout. Our findings demonstrate that unfocused ultrasound sonication can disrupt the blood-brain barrier across the whole brain, including cortex
and deep grey matter nuclei. This can be observed using contrast-enhanced MRI.
1812. Simultaneous Monitoring of Temperature and Magnetization Transfer During HIFU Transmission: In
Vivo Rabbit Investigations
Hsu-Hsia Peng 1 , Teng-Yi Huang 2 , Hsiao-Wen Chung 3 , Shiun-Ying Ju 2 , Yao-Hao Yang 2 , Po-Cheng Chen 4 ,
Yu-Hui Ding 4 , Wen-Shiang Chen 4 , Wen-Yih Isaac Tseng 5
1 Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan; 2 Department
of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan; 3 Department of Electrical
Engineering, National Taiwan University, Taipei, Taiwan; 4 Department of Physical Medicine and Rehabilitation, National Taiwan
University Hospital, Taipei, Taiwan; 5 Center for Optoelectronic Biomedicine, Medical College of National Taiwan University, Taipei,
Taiwan
In this study, an imaging sequence, which simultaneously monitors temperature change and magnetization transfer (MT) contrast at 2-sec temporal
resolution, was applied on rabbit thigh muscle during HIFU sonicaiton to verify in vivo feasibility. The characteristics of better immunity to phase variance
(in contrast to temperature mapping derived from phase images) and clear distinction between heated spot (4.29%¡Ó0.41%) and non-heated region (-
0.19%¡Ó0.30%) of MT, even after turning off HIFU pulse, suggest its usefulness in long-term monitoring. In conclusion, MRI with simultaneous
temperature and MT mapping is an effective technique to evaluate tissue damage for HIFU treatment.
1813. A High Precision MR-Compatible Positioning System for Focused Ultrasound Experiments in Small
Animal Models
Adam Christian Waspe 1,2 , Anthony Chau 1 , Rajiv Chopra 1,2 , Kullervo Hynynen 1,2
1 Imaging Research Discipline, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; 2 Department of Medical Biophysics,
University of Toronto, Toronto, Ontario, Canada
An MR-compatible system was developed for performing focused-ultrasound exposures in preclinical models. A focused-ultrasound transducer attaches to
the positioning system and is submerged within a closed water tank. Sonicating a phantom and measuring the thermal focal zone registers ultrasound and
MRI coordinates. For each axis, a 5 cm travel and 0.1 mm positioning resolution was achieved. The system was constructed with non-magnetic components
and operation of the focused-ultrasound system within the bore during imaging did not result in any mutual interference. This system is used to study the
applications of ultrasound energy for novel therapeutic applications in preclinical animal models.
1814. Optimization of a Four-Coil Array Arrangement for Brain Therapy by MR-Guided Transcranial
Focused Ultrasounds
Line Souris 1 , Najat Salameh 1 , Matthias Korn 1 , Laurent Marsac 2 , Jean-François Aubry 3 , Mathieu Pernot 3 ,
Mickael Tanter 3 , Luc Darrasse 1
1 Imagerie par Résonance Magnétique Médicale et MultiModalité (UMR 8081), Université Paris-Sud, CNRS, Orsay, France;
2 SuperSonic Imagine, Aix en Provence, France; 3 Institut Langevin, ESPCI ParisTech, CNRS UMR 7587, INSERM U979, Paris,
France
MRI is a well-suited candidate for temperature monitoring during the heating with transcranial HIFU. For this application, the body coil is usually used
because of the constraints due to the large sized of the HIFU system and the stereotactic frame surrounding the patient head. This study showed the
improvement of image quality, and therefore temperature sensitivity, by using a dual Flex-coil arrangement. Further improvement is possible by designing
dedicated coil arrays with a larger number of coil elements and integrated EMI filters within the coil architecture to reject any interference of the HIFU shots
with the MR signal.
1815. MR Guided High Intensity Focused Ultrasound for Tumor Ablation in Brain: Preliminary Results
Najat Salameh 1 , Line Souris 1 , Laurent Marsac 2 , Jean-François Aubry 3 , Mathieu Pernot 3 , Benjamin
Robert 2 , Mathias Fink 3 , Luc Darrasse 1 , Mickaël Tanter 3
1 Imagerie par Résonance Magnétique Médicale et MultiModalité (UMR 8081), Université Paris-Sud, CNRS, Orsay, Iles-de-France,
France; 2 SuperSonic Imagine, Aix-en-Provence, France; 3 Institut Langevin, ESPCI ParisTech, CNRS UMR 7587 INSERM U979,
Paris, France
A novel prototype for brain therapy with transcranial focused ultrasound is presented here. The first part of this study showed that this new HIFU system was
fully MR-compatible. Secondly, we optimized a sequence for MR thermometry, and followed the increase in temperature in a gel heated with increasing
power (from 125 to 500 Wac). Finally, we showed it is possible to heat veal brains through a human skull at a high frequency and monitor the heating
process with MRI. After validation on cadaver heads, this work will open new horizons to tumor brain therapy in animals and then in humans.