Gretel Sanabria-Diaz¹, Manina Maja Etter ^2,3, Lester Melie-Garcia^1,4, Johanna Maria Lieb⁵, Marios-Nikos Psychogios⁵, Gregor Hutter^2,3, and Cristina Granziera^1,4
1Department of Medicine and Biomedical Engineering, Translational Imaging in Neurology (ThINK), University Hospital Basel and University of Basel, Basel, Switzerland, ²Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland, ³Division of Neurosurgery, University Hospital Basel, Basel, Switzerland, ⁴Neurologic Clinic and Policlinic, MS Center and Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland, ⁵Department of Neuroradiology, Clinic of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland

A quantitative imaging study is critical to detect cortical brain macrostructural alterations associated with an inflammatory response in hospitalized SARS-CoV-2 patients.  Using automated processing of the 3D high-resolution T1-weighted anatomical images, we found a decrease of cortical gray matter volume and thickness, but not in the surface area related to increased levels in CSF protein, CSF blood/albumin ratio, and CSF EN-RAGE. The anatomical localization of these regions may be the in vivo hallmarks of the virus effect on the brain cortex due to a hyperinflammatory response and associated with neurological deficits presented in acute and post-Covid phases.

Li Jiang^1,2, Jiachen Zhuo^1,2, Steven Roys^1,2, Rosy Linda Njonkou Tchoquessi^1,2, and Rao Gullapalli^1,2
1Center for Advanced Imaging Research, University of Maryland Baltimore, Baltimore, MD, United States, ²Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland Baltimore, Baltimore, MD, United States

Mild traumatic brain injury (mTBI) accounts for the majority of head injuries and is often associated with physical, cognitive, and effective deficits. We used fixel-based analysis (FBA) to investigate the white matter (WM) structural alterations in acute mTBI patients. Three fixel-based metrics were used: fibre density (FD), fibre-bundle cross-section area (FC) and a combination of FD and FC (FDC). We found out that mTBI patients demonstrated reduced FC and FDC in multiple WM tracts and it may suggest that FBA can be used to detect subtle WM changes following mild injuries. 

Reza Rahmanzadeh^1,2, Stefan Herms³, Bettina Burger³, Po-Jui Lu^1,2, Muhamed Barakovic^1,2, Matthias Weigel^1,2, Thanh D. Nguyen⁴, Yi Wang⁴, Francesco La Rosa ^5,6, Meritxell Bach Cuadra ^5,6, Ernst-Wilhelm Radue¹, Jens Kuhle², Ludwig Kappos², Sven Cichon^3,7, and Cristina Granziera^1,2
1Translational Imaging in Neurology Basel, Department of Medicine and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland, ²Neurologic Clinic and Policlinic, Switzerland, Departments of Medicine, Clinical Research and Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland, ³Human Genomics Research Group, Department of Biomedicine, University Hospital and University of Basel, Basel, Switzerland, ⁴Department of Radiology, Weill Cornell Medical College, New York, NY, United States, ⁵Signal Processing Laboratory (LTS5), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, ⁶Radiology Department, Center for Biomedical Imaging (CIBM), Lausanne University and University Hospital, Lausanne, Switzerland, ⁷Institute of Medical Genetics and Pathology, University Hospital Basel, Basel, Switzerland

Despite several large-scale genome-wide association studies (GWAS) have been performed in MS, to date no study explored the relationship between genetic risk factors for MS and the extent of myelin and axon damage in the brain of MS patients, as measured by advanced MRI techniques. Our results identify novel genetic loci that might be associated with myelin and axonal pathology in MS Patients.

Ka-Loh Li¹, Daniel Lewis², Xiaoping Zhu¹, Alan Jackson¹, and Timothy Cootes^1
1Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, United Kingdom, ²Department of Neurosurgery, Salford Royal NHS Foundation Trust,, Manchester, United Kingdom

A limitation of the extended Tofts model (ETM) is that estimates of K^trans, transfer constant, reflect both capillary plasma flow (Fp) and the capillary permeability-surface area product (PS). Other DCE-MRI models can separate out these physiological effects, but such models mandate high-temporal resolution data, compromising spatial resolution and volume coverage. In this in vivo brain tumor study, we demonstrate that incorporating the ETM and an early-timepoints absolute CBF (ET-CBF) method with a dual-temporal resolution, DCE-MRI approach, termed LEGATOS, permits generation of high-spatial resolution maps of K^trans, Fp and PS, allowing high-spatial resolution interrogation of flow and permeability effects. 

Yiming Wang¹, Marco C. Pinho^1,2, Limin Zhou¹, Michael N. Youssef^3,4, Joseph A. Maldjian^1,2, and Ananth J. Madhuranthakam^1,2
1Department of Radiology, UT Southwestern Medical Center, Dallas, TX, United States, ²Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States, ³Department of Neurology, UT Southwestern Medical Center, Dallas, TX, United States, ⁴Harold C. Simmons Cancer Center, UT Southwestern Medical Center, Dallas, TX, United States

In Glioblastoma (GBM) patients undergoing chemoradiation, decreased tumor perfusion can be observed in treatment-responding patients and earlier than changes in tumor volume measured by conventional MRI. Such perfusion changes can be measured by non-contrast Arterial Spin Labeled (ASL) MRI, which is particularly suitable for longitudinal assessment of tumor perfusion. In this study, we performed longitudinal perfusion measurements using ASL MRI in patients with glioblastoma undergoing chemoradiation. Progressive perfusion reduction was observed in a representative patient's enhancing tumor ROIs along with increased ADC values, indicating reduced tumor cellularity, which likely results from treatment responses.

L. Klaassen^1,2,3, M.G. Jaarsma-Coes^1,2, T.A. Ferreira², T.H.K. Vu¹, M. Marinkovic¹, G.P.M. Luyten¹, C.R.N. Rasch³, and J.W.M. Beenakker^1,2,3
1Ophthalmology, Leiden University Medical Center, Leiden, Netherlands, ²Radiology, Leiden University Medical Center, Leiden, Netherlands, ³Radiation Oncology, Leiden University Medical Center, Leiden, Netherlands

The aim of this study was to compare ultrasound and MRI dimension measurements for eye tumours and to determine the most suitable measurement modality. MRI and ultrasound yield similar prominence measurements (median absolute difference 0.3 mm) when tumour extent is visible on both modalities. However, in anteriorly located tumours, MRI measurements are more accurate, and using US for these tumours might lead to an underestimation of tumour diameter. MRI provided insight in 3D tumour geometry, even when tumour extent was difficult to visualize on US, enabling more accurate therapy planning and selection for uveal melanoma patients.

L. Klaassen^1,2,3, M.G. Jaarsma-Coes^1,2, B.M. Verbist², T.H.K. Vu¹, Y.L.B. Klaver^3,4, M.F. Rodrigues^3,4, T.A. Ferreira², C. Nabarro², G.P.M. Luyten¹, C.R.N. Rasch^3,4, M. van Herk⁵, and J.W.M. Beenakker^1,2,3
1Ophthalmology, Leiden University Medical Center, Leiden, Netherlands, ²Radiology, Leiden University Medical Center, Leiden, Netherlands, ³Radiation Oncology, Leiden University Medical Center, Leiden, Netherlands, ⁴Radiation Oncology, HollandPTC, Delft, Netherlands, ⁵Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom

The aim of this study was to assess the inter-observer variation in gross target volume (GTV) delineation of uveal melanoma on MRI. Six observers delineated the GTV in ten different patients on T2-weighted and contrast-enhanced T1-weighted scans. The average interobserver variation appeared slightly higher on T1gd (0.41 mm) compared to T2 (0.35 mm), although the difference was not significant (p=0.12). We recommend to delineate based on the T1gd-weighted scans, as parts of the tumour might be missed on T2.

Serafeim Loukas^1,2, Joana Sa de Almeida¹, Djalel Eddine Meskaldji^1,3, Dimitri Van De Ville^2,4, and Petra Susan Hüppi^1
1Division of Development and Growth, Department of Pediatrics, University of Geneva, Geneva, Switzerland, ²Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, ³Institute of Mathematics, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, ⁴Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland

Resting-state functional connectivity based on simultaneous BOLD oscillations has been described both in preterm infants and fullterm newborns. During this period of rapid cerebral cortex development, different brain activity patterns (networks) have been previously described. Regional changes in spontaneous BOLD signal variability on the other hand reflect local intravoxel BOLD changes related to neural excitability/flexibility. In the present study, we aimed to explore the longitudinal evolution of the BOLD variability between birth and term-equivalent-age (TEA), a period of rapid brain development, in preterm-born infants. Our findings suggest increased variability at TEA as compared to birth in important primary cortices.

Mohammed Salman Shazeeb¹, Zeynep Vardar¹, Ahmet Peker¹, Anna Kuhn¹, Jean Johnston², Precilla D'Souza², Maria T. Acosta², and Cynthia J. Tifft^2
1University of Massachusetts Medical School, Worcester, MA, United States, ²National Institutes of Health, Bethesda, MD, United States

GM1-gangliosidosis is a rare heritable lysosomal storage disorder caused by accumulation of GM1-ganglioside due to deficiency of the lysosomal enzyme b-galactosidase required for sphingolipid degradation. Progressive accumulation of GM1-ganglioside in the central nervous system induces hypomyelination that results in progressive neurodegeneration. This study used quantitative diffusion tensor imaging (DTI) in 20 type II GM1 patients to assess white matter tract changes in the internal capsule and corpus callosum of juvenile and late infantile patients. Several DTI parameters showed significant differences between the patient groups and compared to healthy subjects that may be important to track the progression of the disease.

Mingxiao Zhang¹, Aaron Anderson^2,3, Paul Arnold³, Jason Huston³, William C. Olivero², and Bradley P. Sutton^1,2
1Department of Bioengineering, University of Illinois, Urbana, IL, United States, ²Beckman Institute, Urbana, IL, United States, ³Carle Foundation Hospital, Urbana, IL, United States

Pediatric patients with hydrocephalus rely on ventriculo-peritoneal shunts to drain cerebrospinal fluid (CSF) from the brain. Quick, safe detection of shunt failure is crucial to preventing neurologic injury. Previously, a non-invasive MRI-based monitoring technique, Shunt Flow Enhancement of Signal Intensity (Shunt-FENSI), was proposed for accurate and quantitative CSF flow measurement in the slow flowing shunt. We are introducing a more advanced version, Phase-Sweep FENSI (PS-FENSI) to deal with magnetic field inhomogeneity which can cause changes to the tag effectiveness. This new method is accompanied by new fitting methods to more reliably measure FENSI signals. 

Iris Y. Zhou^1,2, Michael C. Magaletta¹, Molly Mascia^2,3, George A. Alba^2,3, Peter Caravan^1,2, and Sydney B. Montesi^2,3
1Athinoula A. Martinos Center for Biomedical Imaging, Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States, ²Harvard Medical School, Boston, MA, United States, ³Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA, United States

Coronavirus disease 2019 (COVID-19) has been shown to cause pathologic aberrancies in the vascular endothelium. We performed dynamic contrast-enhanced (DCE) MRI on participants with prior COVID-19 to assess differences in pulmonary microvascular perfusion compared with healthy volunteers. Significantly reduced peak enhancement, slower rate of contrast arrival, and longer mean transit time were found in COVID-19 survivors compared to healthy controls, indicating reduced microvascular perfusion months after initial SARS-CoV-2 infection. The DCE MRI readouts can potentially be used as quantitative imaging biomarkers of pulmonary vascular change and may provide important insights into COVID-19 microvascular pathobiology and outcome.

Jessie Han¹, Mingming Wu¹, Selina Rupp¹, Daniela Junker¹, Anna Reik², Meike Wiechert², Hans Hauner^2,3, Marcus R. Makowski¹, Christina Holzapfel², Stefan Ruschke¹, and Dimitrios C. Karampinos^1
1Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany, ²Institute for Nutritional Medicine, School of Medicine, Technical University of Munich, Munich, Germany, ³Else Kroener-Fresenius-Center of Nutritional Medicine, School of Life Sciences, Technical University of Munich, Freising, Germany

Subcutaneous adipose tissue (SAT) dysfunction is key in defining high-risk individuals in obesity. A change in adipose tissue water fraction with weight loss may reflect improvement in blood flow or changes in microstructure of adipose tissue. Single-voxel STEAM Magnetic Resonance Spectroscopy (MRS) and chemical shift encoded-based water-fat separation are non-invasive methods to assess the water fraction and proton density fat fraction (PDFF) of adipose tissue. The present work aims to investigate the feasibility of MRS and water-fat separation to quantify PDFF and evaluate the changes in SAT water fraction in persons with obesity undergoing an 8-week weight loss intervention.