View Presentation Video

Eddy Solomon¹, Gregory Lemberskiy², Steven Baete², Kenneth Hu³, Dariya Malyarenko⁴, Scott Swanson⁴, Amita Shukla-Dave⁵, Stephen E Russek⁶, Elcin Zan², and Sungheon Gene Kim^1
1Radiology, Weill Cornell Medicine, New York, NY, United States, ²Radiology, New York University, New York, NY, United States, ³Radiation Oncology, New York University, New York, NY, United States, ⁴Radiology, University of Michigan, Ann Arbor, MI, United States, ⁵Medical Physics and Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States, ⁶National Institute of Standards and Technology, Boulder, CO, United States

Keywords: Diffusion/other diffusion imaging techniques, Cancer

Cellular-interstitial water exchange time has been suggested to be associated with a number of important cellular properties such as membrane permeability, tumor aggressiveness and treatment response. In this study we investigated the reliability of measuring water exchange times based on diffusivity and diffusional kurtosis at long diffusion times. We used two well-established diffusion phantoms and found that diffusion and kurtosis show stable values over a wide range of diffusion times. In head and neck cancer patients, we found that the Kärger model is a valid model for measuring water exchange time in metastatic lymph node voxels.

WEN JUN HU¹, Anliang Chen¹, and AIlian Liu^1
1The First Affiliated Hospital of Dalian Medical University, Dalian, China

Keywords: Diffusion/other diffusion imaging techniques, Cancer

Tumor deposits (TDs) in rectal cancer have been shown to be an important marker of poor prognosis. Although very similar to lymph node metastasis (LNMs), TDs have unique features in terms of biology and outcome, suggesting that distinguishing between these two entities may be of great importance. Results of this study indicate DWI and DCE-MRI can effectively differentiate TDs and LNMs in rectal cancer, Combination of DWI and DCE-MRI imaging may serve as an effective noninvasive method for differentiation of TDs from LNMs in rectal cancer.

View Presentation Video

Laurin Mordhorst¹, Mohammad Ashtarayeh¹, Maria Morozova^2,3, Luke J. J Edwards², Carsten Jäger², Henriette Rusch³, Tobias Streubel¹, Nikolaus Weiskopf^2,4, Markus Morawski^2,3, and Siawoosh Mohammadi^1,2
1Institute of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ²Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ³Paul Flechsig Institute - Center of Neuropathology and Brain Research, Medical Faculty University of Leipzig, Leipzig, Germany, ⁴Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany, Leipzig, Germany

Keywords: Diffusion/other diffusion imaging techniques, Validation, Histology Connectome Axon radius Deep learning

Robust MRI-based axon radius estimation is sensitive to a tail-weighted estimate of the ensemble-average axon radius, i.e., the effective axon radius ($$$r_{eff}$$$). Existing validation studies of $$$r_{eff}$$$  in the human brain are confounded because the histological gold standard cannot representatively sample the tail of the axon radii distribution due to limited sample size. We compare in vivo, MRI-based $$$r_{eff}$$$ of five healthy adults against a representative histological gold standard of three donors in the human corpus callosum and demonstrate that spatial patterns of the $$$r_{eff}$$$ along the anterior-posterior axis agree between in vivo MRI and ex vivo histology.

View Presentation Video

Tomokazu Tsurugizawa^1,2, Cuong Pham³, Anna Deàs Just³, Benjamin Le Gac³, Dongdong Li³, Bruno Cauli³, and Yuji Komaki^4
1National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan, ²Faculty of Engineering, University of Tsukuba, Tsukuba, Japan, ³Sorbonne University, Paris, France, ⁴Central Institute for Experimental Animals, Kawasaki, Japan

Keywords: Diffusion/other diffusion imaging techniques, Diffusion/other diffusion imaging techniques

The glymphatic system seems to be involved to protect the brain pathologies like Alzheimer’s disease, by the clearance of brain waste1. A previous study showed the apparent diffusion coefficients (ADC) in several brain regions were increased by aquaporin 4 (AQP4) inhibitor2. However, the time course of ADC change has not been investigated. In this study, we showed the time course of ADC change in multiple mouse brain regions following injection of the TGN020 and the effect of TGN020 on volume-dependent intrinsic optical signals in brain slices.

View Presentation Video

Dinank Gupta¹, Tarana P Kaovasia¹, Dave Choi¹, Steven P Allen², Timothy L Hall¹, Zhen Xu¹, and Douglas C Noll^1
1Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States, ²Brigham Young University, Provo, UT, United States

Keywords: Diffusion/other diffusion imaging techniques, Focused Ultrasound, Histotripsy

Histotripsy is a non-invasive, non-thermal focused ultrasound ablation method that mechanically breaks down the target tissue into acellular debris and has shown promising results for brain surgery. Quantifying histotripsy treatment dosage is required to avoid over/under-treatment of the target region. In this work, we assess whether T1, T2 and ADC maps can be utilized to quantify the ablation effect generated by varying histotripsy dosage post-treatment using an ex-vivo bovine brain. We show that only the ADC map is able to visualize the histotripsy ablation. Increasing histotripsy dosage results in increasing ADC.

View Presentation Video

Ricardo Coronado-Leija¹, Hong-Hsi Lee², Els Fieremans¹, and Dmitry S Novikov^1
1Radiology, NYU Grossman School of Medicine, New York, NY, United States, ²Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States

Keywords: Microstructure, Simulations

In this work, we relate a specific feature of brain microstructure, the axon packing correlation length $$$l_c$$$, with parameters of time-dependent diffusion $$$D(t)$$$ obtained from Monte Carlo simulations. We observe that diffusion correlation length estimated from $$$D(t)$$$ shows good correspondence with $$$l_c$$$ estimated from geometries of packed disks with several densities, simple models for axon loss and demyelination, as well as for realistic substrates obtained from segmented electron microscopy.

View Presentation Video

Teresa Scheidt¹, Markus Nilsson¹, Danielle van Westen^1,2, Erik Stomrud^3,4, Oskar Hansson^3,4, and Nicola Spotorno^3
1Diagnostic Radiology, Department of Clinical Sciences, Lund University, Lund, Sweden, ²Image and Function, Skåne University Hospital, Lund, Sweden, ³Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Lund, Sweden, ⁴Memory Clinic, Skåne University Hospital, Malmö, Sweden

Keywords: Diffusion/other diffusion imaging techniques, Alzheimer's Disease

Gray matter microstructural changes appear prior to macrostructural changes in Alzheimer’s disease, these changes can be probed by diffusion MRI. However, different methods can be used to extract metrics in the thin cortical ribbon. The influence of the choice of method on the results has not been investigated yet. In this work, two different methods of extracting diffusion metrics in the cortex are compared, a surface-based approach and gray matter based spatial statistics (GBSS). We improve upon GBSS and show it now yields comparable results to a surface-based method.

View Presentation Video

Eddy Solomon¹, Steven H. Baete², Joseph K. Kim³, Moses Tam³, Zujun Li⁴, Kenneth Hu³, Elcin Zan², and Sungheon Gene Kim^1
1Radiology, Weill Cornell Medical College, New York, NY, United States, ²Radiology, New York University Grossman School of Medicine, New York, NY, United States, ³Radiation Oncology, New York University Grossman School of Medicine, New York, NY, United States, ⁴Medical Oncology, New York University Grossman School of Medicine, New York, NY, United States

Keywords: Diffusion/other diffusion imaging techniques, Treatment

In this study, we evaluated the time-dependence of diffusivity and kurtosis in HPV-positive oropharyngeal squamous cell carcinoma patients before and during chemo-radiation treatment, as part of a study for adaptive de-escalation of the therapy. The non-deescalated patients with less than 40% nodal shrinkage had significantly higher diffusivity and lower kurtosis at pre-treatment than the de-escalated patients with more than 40% nodal volume shrinkage. The water exchange times were longer in the de-escalated patients than in the non-deescalated patients, although not significant. The prognostic accuracy of the pre-treatment imaging parameters was between 0.7 and 0.85.

View Presentation Video

Filip Szczepankiewicz¹, Marcella Safi², Crister Ceberg¹, Michael Gottschalk³, Evangelia Sereti⁴, Anders Bjartell⁴, Oskar Vilhelmsson Timmermand⁵, Linda Knutsson^1,6, Sven-Erik Strand^1,7, and Joanna Strand^2,7
1Medical Radiation Physics, Lund University, Lund, Sweden, ²Hematology, Oncology, Radiation Physics, Lund University, Lund, Sweden, ³Lund University Bioimaging Centre, Lund University, Lund, Sweden, ⁴Translational Medicine, Lund University, Lund, Sweden, ⁵King's College London, London, United Kingdom, ⁶F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, ⁷Dept of Oncology, Lund University, Lund, Sweden

Keywords: Diffusion/other diffusion imaging techniques, Microstructure, Prostate Cancer, Multidimensional MRI, Radiotherapy

We use multidimensional diffusion MRI to monitor longitudinal effect of external radiotherapy in human prostate cancers in mice. The measured dimensions are “diffusion time” and “shape of the b-tensor,” enabling a probe of tissue heterogeneity, microscopic anisotropy and restriction sizes. We show that the diffusivity is highly time dependent in all tumors, and that it is significantly altered by radiotherapy, already within 1-15 days of treatment. The largest effect is seen for the diffusivity and its time dependence, but the isotropic diffusional variance is also impacted. Throughout, histology is used qualitatively to provide plausible interpretations to the observations.

View Presentation Video

Gopal Varma¹, Aaron K Grant¹, Olivier M Girard², Guillaume Duhamel², and David C Alsop^1
1Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, ²CNRS, CRMBM, Aix-Marseille Univ, Marseille, France

Keywords: Microstructure, Quantitative Imaging

Extraction of quantitative parameters of brain tissue microstructure is possible with DTI, inhomogeneous MT (ihMT), and MWF MRI. We examine the ability of the parameters from these techniques to distinguish ex-vivo specimens of the cerebellum from donors with MS relative to non-MS tissue. Significant differences were found for DTI and MT/ihMT metrics in WM, but only for MT/ihMT in GM. Differences between quantitative MT parameters from fits to ihMT data were not significant.

View Presentation Video

Nina Lüthi¹, Francisco J. Fritz¹, Björn Fricke¹, Tobias Streubel¹, Herbert Mushumba², Klaus Püschel², and Siawoosh Mohammadi^1,3
1Department of Systems Neurosciences, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ²Institute of Legal Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany, ³Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

Keywords: Diffusion/other diffusion imaging techniques, Ex-Vivo Applications, fixation, PFA, in-situ MRI, whole human brain

We investigated the longitudinal fixation effect of 4% paraformaldehyde and phosphate-buffered saline on diffusion imaging-derived mean diffusivity (MD) and fractional anisotropy (FA) across deep gray, cortical gray and white matter in human brains using suboptimal and optimal diffusion protocols with varying maximal b-values.
We had two main findings: (1) a suboptimal diffusion protocol led to increased bias in the FA and MD up to 36.26% and 38.11%, the same trend was also observed for the across-brain variation; (2) MD changed by a maximum of 26.42% within the first 14 days in fixative and saturated afterward, whereas FA remained almost constant.

View Presentation Video

Ying Liao¹, Santiago Coelho¹, Filip Szczepankiewicz², Dmitry S. Novikov¹, and Els Fieremans^1
1Radiology, NYU School of Medicine, NEW YORK, NY, United States, ²Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden

Keywords: Diffusion/other diffusion imaging techniques, Diffusion/other diffusion imaging techniques

Combining diffusion and relaxation is promising in probing the tissue microstructure in brain white matter. We designed an optimal diffusion-relaxation protocol with varying b-values, b-tensor shapes and echo times by minimizing the error of parameter estimation. We compared the Standard Model parameters estimated by diffusion-relaxation and diffusion-only data using sensitivity-specificity matrices and test-retest data on volunteers and found excellent agreement. With a comprehensive acquisition protocol, the Standard Model can accurately capture the signal content in white matter with diffusion MRI.

View Presentation Video

Xiao Ma¹, Peter Seres¹, Adam Kinnaird², Christopher Fung³, Thorsten Feiweier⁴, and Christian Beaulieu^1
1Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada, ²Department of Urology, University of Alberta, Edmonton, AB, Canada, ³Department of Radiology, University of Alberta, Edmonton, AB, Canada, ⁴Siemens healthineers, Erlangen, Germany

Keywords: Diffusion/other diffusion imaging techniques, Prostate

Diffusion MRI is used daily in prostate cancer diagnosis. Modification of the diffusion time can probe alterations in prostate microstructure dimensions that may occur with aging or cancer. The mean diffusivity (MD) difference between ‘long’ diffusion time stimulated echo acquisition mode (STEAM) and ‘short’ diffusion time oscillating gradient spin echo (OGSE), and between STEAM and ‘medium’ diffusion time pulsed gradient spin echo (PGSE) showed significant positive linear correlation versus age in peripheral zone of healthy adult prostate (n=15); however, this correlation was not identified in the central gland. Diffusion time sensitivity could reveal age-related prostate tissue microstructural remodeling.

View Presentation Video

Devon Karl Overson^1,2, Yixin Ma³, Trong-Kha Truong^1,2,4, David J. Madden^1,5, Jeffrey R. Petrella^1,2,4, and Allen Song^1,2,4
1Duke-UNC Brain Imaging & Analysis Center, Duke University, Durham, NC, United States, ²Duke Medical Physics Graduate Program, Duke University, Durham, NC, United States, ³Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, ⁴Department of Radiology, Duke University, Durham, NC, United States, ⁵Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States

Keywords: Tractography & Fibre Modelling, Alzheimer's Disease, DTI, Hippocampus, Hippocampal Subfield, Connectome

Changes in intra-hippocampal connectivity caused by early neurodegeneration in specific hippocampal subfields could serve as a biomarker for the early diagnosis of Alzheimer’s disease (AD), years before the onset of symptoms, when the neurodegeneration may still be reversed by treatments. Here, we use high-resolution DTI to compare intra-hippocampal fiber tracks and connectomes across different hippocampal subfields in AD patients and age-matched healthy controls. A significant (p < 0.01) decrease in number of streamlines was found in the AD group compared to the control group for four pairs of subfields, independently of a reduced hippocampal volume affecting nearly all subfields. 

View Presentation Video

Zyad M. Almutlaq^1,2, Sarah E. Bacon³, Daniel J. Wilson³, Nisha Sharma⁴, and David L. Buckley^1
1Biomedical Imaging, University of Leeds, Leeds, United Kingdom, ²Radiological Sciences Department, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia, ³Department of Medical Physics & Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom, ⁴Department of Radiology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom

Keywords: Diffusion/other diffusion imaging techniques, DSC & DCE Perfusion, IVIM

DCE-MRI can provide quantitative estimates of perfusion-related parameters in tumors, such as blood flow and blood volume fraction. It has also been proposed that IVIM MRI can be used to characterize perfusion in addition to microstructure. This proposal remains controversial and requires further investigation. In this study, we investigate the relationship between perfusion-related parameters measured by IVIM and DCE-MRI in a cohort of patients with breast cancer imaged before and after one and two cycles of neoadjuvant chemotherapy.

View Presentation Video

Lars Kasper¹, Zhe Wu¹, Alexander Jaffray^1,2, Sriranga Kashyap¹, and Kamil Uludag^1,3,4
1BRAIN-TO Lab, Techna Institute, University Health Network, Toronto, ON, Canada, ²UBC MRI Research Centre, Vancouver, BC, Canada, ³Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, ⁴Center for Neuroscience Imaging Research, Institute for Basic Science & Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of

Keywords: Diffusion/other diffusion imaging techniques, Diffusion Tensor Imaging, Spiral DWI

Spiral diffusion imaging has been shown to provide substantial SNR advantages (>50%) over state-of-the-art echo-planar imaging, due to the attainable shorter echo times. We investigate the feasibility of this approach on a standard 3T MR system without additional instrumentation. All tools for successful implementation are freely made available, i.e., the characterization measurement for the gradient system using a standard phantom, and an open-source, fast image reconstruction suite in Julia correcting for gradient imperfections, eddy currents, and static B0 off-resonance. We show that this low-cost, accessible solution provides high-resolution diffusion images (1.1mm) in-vivo with reduced geometric distortion and improved quantitative maps.

View Presentation Video

Nicolas Delinte^1,2, Quentin Dessain¹, Manon Dausort¹, Colin Vanden Bulcke^1,2, and Benoit Macq^1
1ICTEAM, UCLouvain, Louvain-la-Neuve, Belgium, ²IoNS, UCLouvain, Louvain-la-Neuve, Belgium

Keywords: Brain Connectivity, Tractography & Fibre Modelling

Short association fibers in the subcortical white matter, also known as U-fibers, represent the connections between neighboring gyri.  Due to the geometry of the cortical folds and the sharp turns along the cortical surface, tractography of U-fibers remains a challenge since increasing the maximum angle between tractography steps also increases the occurence of false positive streamlines. We propose to replace the fixed maximum angle value in tractography algorithms by an angular map, allowing higher angles at the interface between grey and white matter. This enables a more accurate tracking of  U-fibers, while keeping a low number of false positive streamlines. 

View Presentation Video

Marissa Brown¹, Juan Vasquez², Geoffrey Clarke¹, and John Blangero^3
1Radiological Sciences, University of Texas Health Science Center San Antonio, San Antonio, TX, United States, ²School of Medicine, Indiana University, Indianapolis, IN, United States, ³South Texas Diabetes and Obesity Institute, School of Medicine, University of Texas Rio Grande Valley, Brownsville, TX, United States

Keywords: Phantoms, Diffusion/other diffusion imaging techniques, intravoxel incoherent motion, liver, fibrosis

Intravoxel incoherent motion (IVIM) MRI is used to measure quantitative biomarkers of liver fibrosis, but accuracy and reproducibility of various methods requires validation. Six IVIM methods with different acquisition parameters (motion control techniques, b-values, single shot EPI v. SMS) were assessed using the NIST diffusion phantom. The phantom measurements met conformance standards for percent apparent diffusion coefficient (ADC) bias and ADC linearity using a protocol modified for liver MRI. Given that no standard IVIM liver phantom has been developed, the NIST diffusion phantom is shown to work well for validation of liver IVIM acquisitions.