Steven Allen

Rapid imaging techniques can improve patient outcomes and reduce costs during MRI-guided interventions. This talk will cover 5 common strategies for accelerating guidance MR acquisitions and give examples of their implementation from interventional MRI programs groups across the globe. These strategies include using time wisely, reducing fields of view, multiplexing, changing k-space trajectories, skipping data. I conclude with some brief speculation on the potential use of machine learning and AI to further accelerate guidance imaging.

Ali Özen

In this lecture, active device design for cardiovascular interventions will be covered from a technical and a practical perspective. First, various RF coil designs and their working principles will be reviewed. Second, approaches to interface the active devices to the MRI system will be introduced. Afterwards, application of active devices from imaging to tracking will be presented. Finally, challenges and recent advancements in production, and MR safety of the active devices will be discussed.

Allison Payne

MRI guided focused ultrasound combines two innovative technologies to alter tissues non-invasively. The purpose of this talk is to describe the specialized hardware required by the MRI scanner to enable these MR guided focused ultrasound procedures to be performed in the clinical MR environment. While these hardware requirements are typically treatment site specific to some degree, there are key points that can be applied to any MR guided focused ultrasound system. This talk will address three key hardware aspects, specifically the effects of the ultrasound transducer on MR imaging, radiofrequency coils, and acoustically coupling the ultrasound transducer to the patient.

Sherif Nour

Junichi Tokuda

This presentation will overview the technologies and clinical application of MRI-guided robotic prostate biopsy.  Robotic devices have been developed and clinically tested in recent years to address technical challenges in MRI-guided prostate biopsy, such as the limited access to the patient in the bore, and suboptimal needle placement accuracy. I will discuss the technologies for MR-guided robotic biopsy from several key aspects, including system architecture, MRI compatibility, kinematics design, software, imaging sequences, and evaluation of needle placement accuracy. Additionally, I will review some of the published studies that have demonstrated the clinical feasibility of MRI-guided robotic prostate biopsy. 

Daniel Herzka¹, Chris G. Bruce¹, Rajiv Ramasawmy¹, D. Korel A Yildirim¹, Kendall J. O'Brien¹, William H. Schenke¹, Toby Rogers^1,2, Adrienne E. Campbell-Washburn^1,3, Robert J. Lederman ¹, and Aravindan Kolandaivelu^1,4
1NHLBI, Division of Intramural Research, National Institutes of Health, Bethesda, MD, United States, ²Department of Cardiology, Medstar Washington Hospital Center, Washington, DC, United States, ³Biophysics and Biochemistry Branch, Division of Intramural Research, National Institutes of Health, Bethesda, MD, United States, ⁴Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States

This work determined feasibility of visualizing cardiac radiofrequency (RF) ablation lesions at low field (0.55 T) as well as a novel alternative method for targeted tissue destruction: acetic acid chemoablation. Native contrast T1-W imaging and T1 mapping and were carried out in vivo in swine on the day of ablation. Ex vivo high-resolution imaging and histology were used as references. T1 drop was higher for chemoablation (40%) than for RF ablation (19%) relative to myocardium, resulting in significantly higher SNR and CNRs. The visualization of coagulation necrosis from cardiac ablation is feasible using native-contrast low-field MRI.

Matteo Maspero^1,2, Kirsten M. Kerkering^2,3, Tom Bruijnen^1,2, Mark H. F. Savenije^1,2, Joost J. C. Verhoeff¹, Christoph Kolbitsch³, and Cornelis A. T. van den Berg^1,2
1Radiotherapy, Division of Imaging & Oncology, UMC Utrecht, Utrecht, Netherlands, ²Center for Computational imaging group for MR diagnostic & therapy, Center for Image Sciences, UMC Utrecht, Utrecht, Netherlands, ³Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany

The feasibility of generating synthetic CT for lung tumours from 4D MRI was investigated. A combination of multi-view 2D networks proved to be robust against image artefact and generated sCTs that enabled dose calculation on midposition sCTs. The proposed approach facilitates adaptive MR-guided radiotherapy reducing the time from patient positioning to irradiation and enables quality assurance with dose accumulation based on 4D MRI.

Rachel W. Chan¹, Liam S.P. Lawrence², Ryan T. Oglesby², Hanbo Chen³, Brian Keller³, James Stewart³, Mark Ruschin³, Brige Chugh^3,4, Scott MacKenzie³, Mikki Campbell³, Aimee Theriault³, Sten Myrehaug³, Jay Detsky³, Pejman J. Maralani⁵, Chia-Lin Tseng³, Gregory J. Czarnota^1,2,3, Greg J. Stanisz^1,2,6, Arjun Sahgal³, and Angus Z. Lau^1,2
1Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, ²Medical Biophysics, Sunnybrook Research Institute, Toronto, ON, Canada, ³Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, ⁴Department of Physics, Ryerson University, Toronto, ON, Canada, ⁵University of Toronto, Sunnybrook Health Sciences Centre, Medical Imaging, Toronto, ON, Canada, ⁶Department of Neurosurgery and Pediatric Neurosurgery, Medical University, Lublin, Poland

A multi-parametric imaging protocol, for monitoring patients with brain tumors treated using the 1.5T MR-Linac radiotherapy system, is presented with a focus on CEST. Phantom experiments were performed on the MR-Linac using varying concentrations of ammonium chloride mixtures. 24 subjects were included in the analysis. Mixed modelling was used to determine any differences between the gross tumor volume (GTV) and contralateral normal appearing white matter (cNAWM) regions, where three CEST parameters were investigated (MTR_Amide, MTR_NOE and Asymmetry). Results from phantom experiments confirmed detectable CEST asymmetry. Significant differences were found in all three CEST parameters between the GTV and cNAWM.

Mohammed Z Goryawala¹, Eric A Mellon², Saumya Gurbani³, Karthik Ramesh³, Brent D Weinberg⁴, Lawrence Kleinberg⁵, Eduard Schreibmann³, Sulaiman Sheriff¹, Peter B. Barker⁶, Shu Hui-Kuo⁷, Hyunsuk Shim³, and Andrew Maudsley^8
1Radiology, University of Miami School of Medicine, Miami, FL, United States, ²Radiation Oncology, University of Miami School of Medicine, Miami, FL, United States, ³Emory University, Atlanta, GA, United States, ⁴Radiology, Emory University, Atlanta, GA, United States, ⁵Radiation Oncology, Johns Hopkins University, Baltimore, MD, United States, ⁶Radiology, Johns Hopkins University, Baltimore, MD, United States, ⁷Radiation Oncology, Emory University, Atlanta, GA, United States, ⁸Radiology, University of Miami, School of Medicine, Miami, FL, United States

To improve localization of tumor tissue for radiation treatment planning a volumetric MR spectroscopic imaging acquisition was used to identify regions of metabolic abnormality. These regions were then integrated into the clinical treatment plan to target increased radiation dose for the identified volume. In a 3-site clinical trial of 30 patients with newly-diagnosed glioblastoma, the escalated dose resulted in a median overall survival of 23 months, which compares favorably with standard of care, without severe adverse events. This study demonstrates considerable potential for incorporating volumetric spectroscopic imaging into radiation treatment planning protocols.

Dinank Gupta¹, Ning Lu¹, Adam Fox¹, Dave Choi¹, Jonathan Sukovich¹, Badih Junior Daou², Aditya Pandey², Timothy Hall¹, Zhen Xu¹, and Douglas Noll^1
1Biomedical Engineering, The University of Michigan, Ann Arbor, MI, United States, ²Department of Neurosurgery, The University of Michigan, Ann Arbor, MI, United States

Feasibility of transcranial MR-guided histotripsy for an in-vivo large animal model is established. Eight juvenile pigs were treated using an in-house, 128 channel histotripsy array at a wide range of sites around the brain. Target localization was done using fiducials placed on the array using pre-treatment MR images. Lesions were generated in all the pigs and were visualized in post treatment MRI scans and histology. In acute treatment phase, treatment effects were visible on T2*,T2, T1/T2 FLAIR weighted images. This is the first study to exhibit feasibility of in-vivo transcranial MR-guided histotripsy treatment.

Hui Zhou^1,2, Yang Liu³, Xiaojing Long³, Yangzi Qiao¹, Jo Lee¹, Chao Zou^1,4, Xin Liu^1,4, and Hairong Zheng^1
1Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ²The Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, shenzhen, China, ³Research center for medical AI，Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ⁴Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China

The BBB has been opened with millisecond ultrasound in kinds of animals for researching of neurological diseases therapy. Rapid short-pulse (RaSP) ultrasound with a microsecond sequence has been proposed as a minimally disruptive and efficient method for BBB opening in mice and rats. This work quantitatively evaluate the feasibility and safety of BBB opening in non-human primate with RaSP by contrast enhanced MRI. The relative signal enhancement in RaSP with 6% energy deposition reached more than 60% of that with 10 ms long pulse (LP), which shows that RaSP is a practical method for BBB opening in a large-animal model.