13:45 | 1277.
| Dynamic 3D Thermometry in Moving Tissue using Accelerated Stack-of-Radial MRI and an Image-Navigated Multi-Baseline PRF Method Qing Dai1, Shu-Fu Shih1, Omar Z. Curiel2, Jason Chiang1, David S. K. Lu1, Tsu-Chin Tsao2, and Holden H. Wu1 1Radiology, University of California, Los Aneles, Los Angeles, CA, United States, 2Mechanical And Aerospace Engineering, University of California, Los Aneles, Los Angeles, CA, United States Keywords: Thermometry/Thermotherapy, MR-Guided Interventions, Liver, Motion Correction, Radial MRI, Focused Ultrasound Motivation: MRI thermometry faces challenges in moving tissues: intra- and inter-scan motion, limited spatio-temporal resolution, and constrained spatial coverage. These obstacles result in temperature mis-calculations, compromising treatment safety and efficacy. Goal(s): To develop an image-navigated 3D thermometry method to simultaneously track respiratory motion and temperature in moving tissue. Approach: A stack-of-radial sequence was combined with compressed sensing reconstruction to obtain dynamic 3D images. An image-navigated multi-baseline proton resonance frequency shift (PRF) method was developed to generate motion-resolved temperature maps with tissue tracking. Results: The proposed method achieved 24-30 slice coverage with a temporal resolution <1 second/volume and mean absolute error <2 degrees during motion. Impact: The proposed method could improve the safety and efficacy of MRI-guided thermal therapies through reliable temperature monitoring in moving tissues. The capability to simultaneously track motion and temperature evolution enables feedback control, including focused ultrasound beam steering in moving organs. |
13:57 | 1278.
| MR Thermometry with High Precision and Temporal Resolution by Quadratic Phase MR Fingerprinting Sarah Garrow1, Rasim Boyacioglu1, Kathryn E Keenan2, Mark Griswold1, and William Grissom1 1Case Western Reserve University, Cleveland, OH, United States, 2National Institute of Standards and Technology, Boulder, CO, United States Keywords: Thermometry/Thermotherapy, Thermometry Motivation: Proton resonance frequency (PRF)-shift thermometry is the current standard for MR-temperature monitoring in interventional procedures. However, the long TE required for phase contrast induces signal dropout and increases sensitivity to metal and motion artifacts. Goal(s): Use quadratic RF phase (qRF) MR fingerprinting to image off-resonance frequency for thermometry at a real time frame rate. Approach: Because PRF change is much more sensitive to temperature change in aqueous tissue than T1/T2, we propose a “lightweight” constant low-flip-angle MRF sequence optimized for 3s or less frame rate to measure temperature from the PRF shift. Results: We implemented qRF-MRF thermometry with high spatiotemporal resolution. Impact: A
thermometry method with high temporal resolution that does not suffer from
signal dropout at high temperatures can enable more accurate temperature
monitoring for MR-guided interventional procedures. Additionally, it has
potential to be more robust to motion artifacts. |
14:09 | 1279.
| An MRF approach for Simultaneous T1- and PRFS-based 3D MR-Thermometry Moritz Gutt1, Dominik Horstmann1, Frank Wacker1, Bennet Hensen1, and Marcel Gutberlet1 1Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany Keywords: Thermometry/Thermotherapy, Thermometry Motivation: The classical PRFS-based approach to MR-thermometry cannot be used in adipose tissue and is vulnerable to susceptibility artifacts. Nonetheless, the PRFS-based method is quite accurate in aqueous tissue when no severe susceptibility artifacts occur. Goal(s): A simultaneous measurement of T1 could be used to account for susceptibility artifacts and perform thermometry in adipose tissue. Approach: An MRF sequence was designed to measure T1 and the PRF at the same time. It was tested during a microwave ablation on a liver phantom. Results: The PRFS-based temperature maps had a higher temperature accuracy while the T1-based temperature maps performed better in predicting the ablation zone. Impact: It was shown that simultaneous T1- and PRFS-based 3D-Thermometry is possible using MRF. While the T1 proved to be more robust to susceptibility-induced errors, the PRF had a better temperature accuracy. A combined approach could provide a more accurate MR-thermometry. |
14:21 | 1280.
| Real-time automatic multipoint temperature regulation during MRI-guided Laser-induced Thermotherapy (MR-LITT) Manon Desclides1,2, Valéry Ozenne1, Pierre Bour2, Guillaume Machinet3, Christophe Pierre3, Stéphane Chemouny2, and Bruno Quesson1 1University of Bordeaux, CNRS, CRMSB, UMR 5536, IHU Liryc, Bordeaux, France, 2Certis Therapeutics, Pessac, France, 3ALPhANOV, Talence, France Keywords: MR-Guided Interventions, MR-Guided Interventions, LITT, laser, ablation, thermometry Motivation: Current Laser devices used during MR-guided LITT can use single or multiple fibers to create coagulation necrosis, but do not provide opportunities for precise temperature control in tissue. Goal(s): We present an automatic control algorithm combined with a multi-source laser that allows the temperature to be forced to follow predefined temperature profiles. Approach: Fast, multi-slice thermometric data are processed on the fly to achieved efficient volumetric temperature regulation of multiple laser sources simultaneously. Results: We offer a precise and rapid volumetric temperature control solution combined with multi-source LITT to create conformal ablation volumes larger than those achieved with a single fiber. Impact: Automatic volumetric temperature regulation of multisource LITT combined
with real-time multislice MRI thermometry allows better control of local thermotherapies
in soft tissues. |
14:33 | 1281.
| Evaluation of Magnetic Resonance Mediated Radiofrequency Ablation in Bovine Liver Tissue Using Textile Antenna-Enhanced MR Thermometry. Sana Ullah1, Sukhoon Oh2, and Hyoungsuk Yoo3 1Seoul Institute of Technology, School of Electrical and Biomedical Engineering, Hanyang University, Seoul, Korea, Republic of, 2Bio-chemical Analysis Team, Korea Basic Science Institute, Cheongju, 28119, South Korea, Cheongju, Korea, Republic of, 3Department of Biomedical Engineering and Department of Electronic Engineering, Hanyang University, Seoul, Korea, Republic of Keywords: Non-Array RF Coils, Antennas & Waveguides, Thermometry, Magnetic resonance-mediated radiofrequency ablation, antenna Motivation: Magnetic resonance-mediated radiofrequency ablation (MR-RFA) combines diagnostic and therapeutic functions within MRI scanners, and its significance has grown rapidly, particularly in tumor treatment diagnosis. Goal(s): In this study, a 3T Philips MRI scanner is channeled toward the ablation site in the bovine liver by means of an antenna and a needle, with the objective of generating RF heating at the tumor location. Approach: MR thermometry was used to evaluate the MR-RFA procedure and predict local specific absorption rate (SAR) escalation and temperature increase. Results: Our research demonstrated that temperature maps with a 73 oC peak value were observed at the needle tip. Impact: In contrast to existing ablation designs, this design provides enhanced patient comfort, localized heating, minimal skin burns, and avoids the use of external RF power sources, all while ensuring there is no distortion in MR images. |
14:45 | 1282.
| Patient-specific targeting of VIM using THOMAS segmentation predicts post-MRgFUS side effects: a retrospective evaluation Sonoko Oshima1,2, Asher Kim1,3, Xiaonan Richard Sun4, Ziad Rifi4, Katy A. Cross5, Katherine A. Fu5, Benjamin M. Ellingson1,2,3,4,6, Noriko Salamon2, Ausaf A. Bari4, and Jingwen Yao1,2,3 1UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, University of California, Los Angeles, Los Angeles, CA, United States, 2Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States, 3Department of Bioengineering, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, Los Angeles, CA, United States, 4Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States, 5Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States, 6Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States Keywords: MR-Guided Focused Ultrasound, MR-Guided Interventions Motivation: Precise and personalized targeting for MR-guided focused ultrasound (MRgFUS) is desired to ensure treatment efficacy and avoid side effect. Goal(s): To assess THalamus Optimized Multi Atlas Segmentation (THOMAS) on white-matter nulled MRI for targeting of the ventral intermediate (VIM) thalamic nucleus in MRgFUS for tremor patients. Approach: We retrospectively assessed the relationships of standard indirectly targeted coordinates, post-FUS lesions, and THOMAS segmentation with post-FUS side effects and tremor scores in patients who underwent VIM-MRgFUS. Results: In patients who exhibited side effects, FUS lesions had a smaller overlap with THOMAS-based VIM segmentation and were located more inferiorly. Impact: THOMAS is a novel automated thalamic segmentation tool which may aide in
the targeting of the VIM nucleus,
potentially reducing side effects and improving treatment outcomes in MRgFUS
for patients with tremor. |
14:57 | 1283.
| First Evidence of sustained reduction of Essential Tremor with MR-Guided Low-Energy Ultrasound Neuromodulation Nadya Pyatigorskaya1,2, Thomas Bancel3, Benoit Beranger4, Melanie Didier4, Maxime Daniel3, Eric Bardinet4, Mathieu Santin4, Sara Fernandez Vidal4, Cécile Galléa1, Itay Rachmilevitch5, Yeruham Shapira5, Alexandre Dizeux3, David Attali3, Mickael Tanter3, David Grabli6, Marie Vidailhet1, Stephane Lehericy1, Carine Karachi6, Elodie Hainque1, and Jean-Francois Aubry3 1MOVIT team, Sorbonne Université, Inserm U1127, CNRS 7225, Hôpital Pitié-Salpêtriere, ICM, Paris, France, 2Neuroradiology, APHP, Sorbonne universite, Paris, France, 3Inserm U1273, ESPCI Paris, CNRS UMR8361, PSL University, Physics for Medicine Paris, Paris, France, 4Centre de NeuroImagerie de Recherche – CENIR, Sorbonne Université, Inserm U1127, CNRS 7225, Hôpital Pitié-Salpêtriere, ICM, Paris, France, 5Insightec, Tirat Carmel, Israel, 6Sorbonne Université, Inserm U1127, CNRS 7225, Hôpital Pitié-Salpêtriere, ICM, Paris, France Keywords: MR-Guided Focused Ultrasound, Focused Ultrasound, MRgFUS, neuromodulation, essential tremor, thermometry Motivation: Transcranial Ultrasound Stimulation (TUS) is a non-invasive technology for brain stimulation, particularly suited for the neuromodulation of deep brain structures. Goal(s): We investigated the behavioral effects of low-energy TUS in the thalamus in Essential Tremor patients scheduled for MR-guided ultrasound treatment. Approach: Two targets were tested: the ventral intermediate nucleus of the thalamus (VIM) and the dentato-rubro-thalamic tract (DRT). MRI was used for procedure guidance and monitoring. The effect was recorded using MR-compatible accelerometers. Results: VIM low-energy neuromodulation induced transient change in tremor power (p-value< 0.001). DRT neuromodulation reduced tremor power (p-value<0.001) with a sustained post-effect, without MR-thermometry exhibiting any significant thermal rise. Impact: High precision focusing enhanced by state of the art transcranial aberration correction allowed unprecedent transient tremor reduction in Essential Tremor patients following low-energy thalamic ultrasound stimulation under MRI guidance. |
15:09 | 1284.
| Low-intensity focused ultrasound with continuous theta burst stimulation induces human primary motor cortex functional connectivity changes Wei-Chih Yang1, Kai-Hsiang Stanley Chen2, Yih-Chih Jacinta Kuo2, Yan-Siou Dong2, Gin-Shin Chen3, and Yao-Chia Shih1 1Graduate Institute of Medicine, Yuan Ze University, Taoyuan City, Taiwan, 2Department of Neurology, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan, 3Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan Keywords: Other Interventional, fMRI (resting state) Motivation: Combining low-intensity transcranial focused ultrasound stimulation (TUS) akin to continuous theta burst stimulation (cTBS) setting (ctbTUS) with cTBS over M1 can be a potential strengthening non-invasive neuromodulatory method. Goal(s): To understand the neuroplasticity in response to ctbTUS or simultaneous ctbTUS+cTBS. Approach: Resting-state fMRI with seed-based analysis with seeds of M1 and its first dorsal interosseous (FDI) muscle representation (M1FDI) was used to assess functional connectivity (FC) changes due to cTBS, ctbTUS, or ctbTUS+cTBS. Results: We replicated M1-FC degradations in ipsilateral sensorimotor regions due to cTBS, and verified the potential synergic effect of ctbTUS+cTBS on M1-FC decreases in supplementary motor area. Impact: Our study is the first to use resting-state fMRI to investigate FC changes within motor network due to either cTBS, ctbTUS, or ctbTUS+cTBS stimulations on left M1. The results help understand the potential of ctbTUS+cTBS to be a novel therapy. |
15:21 | 1285.
| Acute versus chronic ventral lateral thalamus intrinsic connectivity after MR-guided focused ultrasound thalamotomy for essential tremor Darren Laree Clark1, Conrad Rockel1, Samuel Pichardo1, Tejas Sankar2, Fady Girgis3, Camila Aquino4, Davide Martino4, Zelma H.T Kiss3, and G. Bruce Pike1 1Departments of Radiology and Clinical Neurosciences, University of Calgary, Calgary, AB, Canada, 2Department of Surgery, University of Alberta, Edmonton, AB, Canada, 3Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada, 4Departments of Community Health Sciences and Clinical Neurosciences, University of Calgary, Calgary, AB, Canada Keywords: Functional Connectivity, Focused Ultrasound, Essential Tremor, fMRI, Longitudinal Motivation: To address the gap in understanding the longitudinal impact of MR-guided focused ultrasound (MRgFUS)-thalamotomy on motor network connectivity in essential tremor (ET). Goal(s): To elucidate the changes in functional connectivity within the motor network following MRgFUS thalamotomy, distinguishing between acute and chronic phases. Approach: Connectivity changes in the ventrolateral (VL) thalamus of 19 ET patients were tracked using fMRI at three intervals—pre-operation, one day, and three months post-MRgFUS. Results: Initially, both VLs showed diminished connectivity with sensorimotor regions. By three months, left VL had enhanced connections with associative and visual areas, while right VL demonstrated sustained reduced sensorimotor connectivity, reflecting hemisphere-specific functional reorganization. Impact: Mapping evolving connectivity of ventrolateral thalamus after MR-guided focused ultrasound (MRgFUS) thalamotomy enables tailored essential tremor treatments, potentially yielding better outcomes and informing treatment parameters, while also providing putative biomarkers for treatment efficacy and broader insights into neurological network management. |
15:33 | 1286.
| 3D Whole-heart T1-weighted Imaging in a Two-minute Free-breathing Scan for Radiofrequency Ablation Lesion Assessment Jaykumar H. Patel1,2, Philippa R.P. Krahn1,2, Terenz Escartin1,2, Calder D. Sheagren1,2, Labonny Biswas2, Jen Barry2, Melissa Larsen2, and Graham A. Wright1,2 1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada Keywords: MR-Guided Interventions, Data Acquisition, Lesion Characterization, Radiofrequency ablation, 3D High-resolution Imaging, 3D Cone Trajectory Motivation: MRI-guided arrhythmia interventions require fast, high-resolution 3D images for comprehensive intraprocedural assessment of radio-frequency ablation lesion size and depth. Goal(s): Demonstrate similar volumetric lesion quantification between ground-truth respiratory-navigated Cartesian imaging and a novel free-breathing 3D cone-trajectory sequence.
Approach: 4 healthy Yorkshire swine were ablated inside the MRI scanner, with 12 lesions prescribed in total. Volumetric analysis was performed for both Cartesian and 3D cones imaging.
Results: Non-contrast T1-weighted 3D cones imaging with a highly accelerated scan time less than two minutes demonstrated similar lesion volumes to the slower 3D Cartesian sequence.
Impact: Currently, non-contrast ablation lesion assessment in patients requires 5-10 minutes, depending on breathing patterns. The free-breathing 3D cone trajectory sequence presented here is a time-efficient method for lesion characterization that is feasible for intraprocedural applications. |