Aliya Anil¹, Ashely M Stokes¹, Renee Chao¹, Leland Hu², Lea Alhilali³, John P Karis³, Laura C Bell⁴, and C Chad Quarles^1
1Division of Neuroimaging Research and Barrow Neuroimaging Innovation Center, Barrow Neurological Institute, Phoenix, AZ, United States, ²Mayo Clinic Arizona, Phoenix, AZ, United States, ³Southwest Neuroimaging at Barrow Neurological Institute, Phoeix, AZ, United States, ⁴Genentech, South Francisco, CA, United States

Reliable differentiation of tumor recurrence and treatment effects in glioblastoma patients is still a prevailing challenge. The purpose of this study is to identify the optimal threshold for generating fractional tumor burden (FTB) maps derived from single-dose, dual-echo based standardized relative cerebral blood volume measurements. To establish the threshold, dual-echo data was compared to the well-validated, double-dose single echo standardized FTB map. In summary, with the optimized threshold, the single-dose, dual-echo approach yielded FTB maps that strongly agreed with the reference standard, providing a compelling option for clinical use.

Nina Fultz^1,2,3, Hongbae Jeong¹, Stephanie D. Williams^1,3, Daniel E.P. Gomez^1,3, Beverly Setzer^1,3, Tracy Warbrick⁴, Manfred Jaschke⁴, Giorgio Bonmassar¹, and Laura D. Lewis^1,3
1Athinoula A. Martinos Center for Biomedical Engineering, Charlestown, MA, United States, ²Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark, ³Department of Engineering, Boston University, Boston, MA, United States, ⁴Brain Products GmbH, Gilching, Germany

EEG provides valuable clinical information, but EEG nets produce artifacts in MRI and CT images, preventing these modalities from being combined in typical clinical practice. We tested whether a new MR-compatible EEG net, called the R-Net-MR-IT, could produce high-quality clinical and research images. We assessed image quality in CT and MR images on a phantom with a conventional net, R-Net-MR-IT, and with no net. We then performed the same comparison in humans, as well as fMRI scans. Our results show that the R-Net-MR-IT enables acquisition of high quality CT and MR images, with minimal artifact from EEG hardware. 

Rebecca Susan Dewey^1,2,3, Robert Dineen^1,4,5, Matthew Clemence⁶, Olivier Dick⁷, Richard Bowtell¹, and Pádraig Kitterick^8
1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, ²Hearing Sciences, Division of Mental Health and Clinical Neurosciences, School of Medicine, University of Nottingham, Nottingham, United Kingdom, ³Hearing Theme, NIHR Nottingham Biomedical Research Centre, Nottingham, United Kingdom, ⁴Imaging Theme, NIHR Nottingham Biomedical Research Centre, Nottingham, United Kingdom, ⁵Radiological Sciences, Division of Mental Health and Clinical Neurosciences, School of Medicine, University of Nottingham, Nottingham, United Kingdom, ⁶Philips Healthcare, Best, Netherlands, ⁷Radiology Department, Queens Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom, ⁸National Acoustic Laboratories, Sydney, Australia

A cochlear implant (CI) contains a magnet implanted under the scalp. MRI of CI users is associated with safety concerns, significant discomfort, and image distortion. A CI placed under a swimming cap is a feasible tool for observing the effect of CI location on image usability within a single subject and potentially informing surgical planning. 35-70% of radiological features in the head were deemed unaffected by the implant. Online survey results highlight the need for consistent publication of clear, succinct, and standardised information for healthcare professionals and CI users. CI user consultation is scarce, meaning their views are often neglected.

Kwok-Shing Chan¹, Maxime Chamberland¹, and José P Marques^1
1Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands

In this study, we evaluate the test-retest repeatability of the recently developed multi-compartment relaxometry method for myelin water imaging (MCR-MWI). Cross-protocol repeatability is also studied using 3 GRE protocols with different echo spacing and TR. Good cross-session and cross-protocol repeatability is observed for MCR-MWI. Additionally, tissue parameters along 8 major white matter bundles are studied, and myelin water fraction is the most robust tissue parameter across various protocol settings.

Amy FD Howard¹, Istvan N Huszar¹, Michiel Cottaar¹, Greg Daubney², Alexandre A Khrapitchev³, Rogier B Mars^1,4, Jeroen Mollink¹, Lea Roumazeilles², Connor Scott⁵, Adele Smart⁵, Jerome Sallet², Saad Jbabdi¹, and Karla L Miller^1
1Wellcome Centre for Integrative Neuroimaging (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, ²Wellcome Centre for Integrative Neuroimaging, Experimental Psychology, Medical Sciences Division, University of Oxford, Oxford, United Kingdom, ³MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom, ⁴Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands, ⁵Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom

Microscopy data can provide detailed descriptions of how cortical microstructure varies across the brain. However, the relationship between cortical microstructure and MRI signals remains relatively unexplored. Here we develop a pipeline to extract cortical profiles from co-registered MRI and microscopy data in the BigMac dataset. We compare cortical profiles of cell density and microstructural dispersion from Nissl-stained histology slides with matched profiles from structural and diffusion MRI. Using CCA we find modes of microstructure variation common to microscopy and structural MRI, but not diffusion, indicating variable sensitivity of the MR metrics to brain-wide variations in Nissl-stained cytoarchitecture.

Pratik Talati^1,2, Benjamin Chun², Patrick Clark², Anthony Ranasinghe², Mohamed E. El-Abtah², Melanie Fu², Julian He³, Otto Rapalino⁴, R. Gilberto Gonzalez⁴, Jorg Dietrich⁵, Elizabeth R. Gerstner⁵, and Eva-Maria Ratai^2
1Neurosurgery, Massachusetts General Hospital, Boston, MA, United States, ²A. A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, ³Radiology, Massachusetts General Hospital, Boston, MA, United States, ⁴Neuroradiology, Massachusetts General Hospital, Boston, MA, United States, ⁵Neuro-oncology, Massachusetts General Hospital, Boston, MA, United States

Patients with recurrent glioblastoma (rGBM) are often started on anti-angiogenic therapy, making it challenging to determine disease progression with standard MR methods. We performed a prospective analysis on 14 patients with rGBM utilizing MR spectroscopy and DSC-perfusion imaging to investigate metabolic changes before and 4 weeks after anti-angiogenic therapy. We found that anti-angiogenic therapy significantly decreases relative tumor hyperperfusion values of CBV and CBF and uncouples a correlation between CBV and CBF with Lac/c-Cr. Baseline hyperperfusion values can stratify longer-term from shorter-term survivors at nine months. Further investigation into the early stages of anti-angiogenic therapy are warranted.