|Thermal Therapy & Focused Ultrasound|
MRI-Guided Midline Laser Glossectomy in Porcine Models: Evaluation of
Safety and Efficacy for Reducing Tongue Base Volume
Sherif G. Nour1, 2, Jamal J. Derakhshan, Simi Paul1, Jens O. Heidenreich1, Nathan Cross2, Fadi W. Abdul-Karim1, Jeong J. Park, Jeffrey L. Sunshine1, Jeffrey L. Duerk1
1University Hospitals Case Medical center / Case Western Reserve University, Cleveland, Ohio, USA; 2School of Medicine / Case Western Reserve University, Cleveland, Ohio, USA
Reducing tongue base volume has been shown to improve clinical outcomes in patients with obstructive sleep apnea (OSA). A technique for percutaneous laser ablation of the tongue base entirely guided and monitored under MRI is described and tested on porcine models. The ability to safely create large, therapeutic-type ablations within the tongue base utilizing this technique and the effect of this single-session treatment on tongue base shrinkage were specifically evaluated. Both safety and efficacy have been demonstrated. These results represent the first use of IMRI technology to achieve laser-induced glossectomy and constitute promising basis for future treatment of OSA patients.
MR Targeting Guidance and MR Thermometry for Radiofrequency Ablation
in Patients with Liver Tumours on an Interventional 1.5T Platform
Alexandru Cernicanu1, Matthieu Lepetit-Coiffe1, Magalie Viallon1, Sylvain Terraz1, Christoph D. Becker1
1Geneva University Hospital, Geneva, Switzerland
With a closed-bore 1.5T MR system, clinical treatment of metastatic liver tumours (under 2.5 cm in diameter) using RF ablation technique was studied regarding targeting and real-time MR temperature monitoring; Based on a fully-balanced SSFP interleaved radial acquisition, targeting of the deep-situated tumour was achieved in about 22±10min; The RF device was made MR compatible in order to perform MR thermometry with a respiratory-triggered rapid gradient echo-echo planar imaging acquisition; MR temperature accuracy of 1.6±0.5 C was obtained in a non-heated region. Long axis diameter of RF lesion was 3.4±0.7cm overlapping the tumour in 14 of 15 nodules (confirmed both by 2-days-later-CT and 1-month-later-MR clinical images).
MR-Guided HIFU Thermotherapy with a Robotic Assistance System
Axel Krafft1, Jürgen Jenne1, Jaane Rauschenberg1, Wolfhard Semmler1, R Jason Stafford2, Michael Bock1
1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany; 2The University of Texas, MD Anderson Cancer Center, Houston, USA
High intensity focused ultrasound (HIFU) is a non-invasive treatment modality which is often monitored by MR temperature measurements to assess and control thermal target tissue ablation. In this work a fixed-focus HIFU transducer was for the first time combined with a fully MR-compatible robotic assistance system originally designed for percutaneous MR-guided needle interventions. This combined system is tested for its suitability for MR-guided focus ultrasound applications in a phantom and an in vivo experiment. The combined system potentially offers greater flexibility than existing HIFU setups and can achieve a high geometric precision in very short positioning times.
Volumetric HIFU Ablation Under 3D Guidance of Rapid MRI Thermometry
Max Köhler1, Charles Mougenot2, 3, Bruno Quesson3, Julia Enholm1, Brigitte Lebail4, Christophe Laurent5, Chrit Moonen3, Gösta Ehnholm1
1Philips Medical Systems, Vantaa, Finland; 2Philips Medical Systems, France; 3Laboratory for Molecular and Functional Imaging, Bordeaux, France; 4Pellegrin Hospital, Bordeaux, France; 5Saint André Hospital, Bordeaux, France
A volumetric sonication method in conjunction with a simultaneous rapid volumetric thermal monitoring is introduced as a safe, fast and accurate alternative to current point-by-point sonication methods. This study on in-vivo pig thighs demonstrates an improved ablation efficiency and homogeneity with increased sonication volumes. Apparent lesion volume dimensions as seen from the thermal dose maps were in good agreement with corresponding non-perfused contrast enhanced dimensions.
3.0-T MRI-Guided Focused Ultrasound Ablation Versus MRI-Guided
Needle-Wire Placement for the Pre-Operative Localization of Non-Palpable
Breast Tumors: An Experimental Study
Annemarie Caroline Schmitz1, 2, Maurice A. A. J. van den Bosch2, Viola Rieke2, Fred M. Dirbas2, Kim Butts Pauly2, Willem P.T.M. Mali1, Bruce L. Daniel2
1University Medical Center Utrecht, Utrecht, Netherlands; 2Stanford University Medical Center, Stanford, USA
The purpose of this experimental study is to compare the accuracy of MRI-guided focused ultrasound ablation(MRI-gFUS) versus MRI-guided needle-wire placement(MRI-gNW) for the localization of non-palpable breast tumors. Sixteen turkey breasts were used. An artificial tumor was created. MRI-gFUS localization(n=8) was performed with the ExAlblate 2000 system(Insightec). No case of positive margins was found in the FUS-group(0%) and 2 cases in the NW-group(25%)(P=0.5). The mean minimum tumor-free margin±SD in the FUS-group was significantly larger(4.7±2.9mm), than the NW-group(0.9±1.4mm)(P=0.004).The results of this experimental study indicate that MRIg-FUS is as accurate as MRIg-NW for pre-operative localization of non-palpable breast tumor.
Endoluminal Ultrasound Applicator with an Integrated RF Coil for
High-Resolution MRI-Guided HICU Thermotherapy
Mihaela Rata1, 2, Rares Salomir1, Reiner Umathum3, Jurgen Jenne3, François Cotton, 24, Cyril Lafon1, Michael Bock3
1INSERM, U 556, Lyon, France; 2UCBL 1, Lyon, France; 3DKFZ, Heidelberg, Germany; 4CHU Lyon Sud, Lyon, France
High intensity contact ultrasound (HICU) under MRI guidance may provide minimally invasive treatment of endocavitary digestive tumors in the esophagus, colon or rectum. In this study, miniature receive-only coils were integrated into an endoscopic ultrasound applicator to offer high resolution MRI guidance of thermotherapy. The integrated coils provided significantly higher sensitivity than a 4-element extracorporeal phased array coil and the standard deviation of the MR thermometry (SDT) improved by to a factor of 7 at 10 mm depth in tissue. Half millimeter resolution became feasible for fast MR thermometry while providing an excellent SDT (0.3 C). The endoscopic device was actively operated under automatic temperature control, demonstrating very accurate performance.
In Vivo MRI-Monitoring of Gadodiamide Release from
Phosphatidylglyceroglycerol Containing Thermosensitive Liposomes in
Heated and Non-Heated Tumors
Michael Peller1, Alenka Schwerdt2, Martin Hossann3, Herbert M. Reinl4, Tungte Wang3, 5, Lars H. Lindner3, 6, Maximilian Reiser
1University Hospital of Munich, Munich, Germany; 2Ludwig-Maximilians University, Munich, Germany; 3University Hospital of Munich, Germany; 4Department of Clinical Radiology, Germany; 5GSF-National Research Center for Environment, Neuherberg, Germany; 6 GSF-National Research Center for Environment, Neuherberg, Germany
Purpose of this study was to investigate the dynamics of mild temperature induced contrast agent release from phosphatidylglyceroglycerol containing thermosensitive liposomes with encapsulated Gd-DTPA-BMA (Gd-TSL) in the presence of tumor perfusion, using a clinical experimental setting. Tumor bearing mice were investigated at 1.5T after intravenous injection. The temperature induced release of contrast agent at 42 C causes a fast and strong increase of T1-weigthed signal. Intraindividual comparison of heated and non-heated tumors showed a significant higher contrast agent release in heated tumors. This demonstrates the potential of Gd-TSL for monitoring moderate regional hyperthermia in tumor treatment concepts in a clinical MRI-setting.
In Vivo Visualization of an Optical Reporter Gene Expression
Transported by a Cellular Vector and Locally Activated by MRI Guided
HIFU in Rat Kidney
Omer Eker1, Bruno Quesson1, Nora Frulio1, Colette Deminiere2, Chrit Moonen1, Franck Couillaud1, Nicolas Grenier1
1Laboratory IMF, Bordeaux, France; 2CHU Pellegrin, Bordeaux, France
Gene therapy using a cellular vector requires efficient targeting and control of the activation of the transgene of interest. Genetically modified C6 cells expressing Luciferase under a heat sensitive promoter have been injected in the renal artery and their intrarenal distribution visualized by Bioluminescence imaging. Two days after injection, kidneys were focally heated non invasively with HIFU under MRI thermometry automatic control, with different heating conditions. Presence of these cells in the kidney were successfully detected by Bioluminescence imaging and the zones emitting light corresponded to the heated region, indicative of successful in vivo targeting and control of transgene activation.
MRI-Guided Focused Ultrasound-Enhanced Chemotherapy of 9L Rat
Gliosarcoma: Survival Study
Lisa Hsu Treat1, 2, Yongzhi Zhang1, Nathan McDannold1, Kullervo Hynynen1, 3
1Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, USA; 2Harvard-MIT Health Sciences and Technology, Cambridge, Massachusetts, USA; 3Sunnybrook Health Sciences Centre, Toronto, Canada
We investigated the impact of MRI-guided focused ultrasound-enhanced delivery of doxorubicin to brain on survival in rats with 9L gliosarcoma. In this study, we have shown that targeted drug delivery by MRI-guided focused ultrasound significantly improves survival time in rats with aggressive glioma, compared to chemotherapy alone (0.02< p<0.05). Such demonstrated efficacy in an in vivo tumor model represents a large step forward in the development of this technique toward treating patients with disorders of the central nervous system.
MRI Monitoring of Ultrasound-Targeted Microbubbles
April M. Chow1, 2, Chi-tat Chiu1, Ke Xia Cai1, Ed X. Wu1
1The University of Hong Kong, Pokfulam, Hong Kong
Ultrasound-targeted Microbubble Destruction (UTMD) has been used to deliver genes or drugs to specific tissues utilizing microbubbles cavitation and sonoporation effect through guidance of ultrasound imaging. However, ultrasound imaging cannot visualize soft tissues adequately and non-site-specific therapeutic effect may result from the imaging ultrasound irradiation. MRI would be the most effective imaging modality to guide UTMD for genes or drugs delivery due to its better soft tissue delineation without interaction with microbubbles. In this study, we demonstrate that MRI can detect microbubble cavitation and MRI monitoring of UTMD is feasible.