Hongxi Zhang¹, Hua Li², Zhipeng Shen¹, Yi Zhang³, and Dan Wu^3
1Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China, ²Nemours AI duPont Hospital for Children, Wilmington, DE, United States, ³Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China

Diffusion-time dependent diffusion MRI has shown potential in probing tumor microstructure. This study investigated the feasibility of time-dependent dMRI to map brain tumor microstructure in a pediatric population at 3T. Oscillating and pulsed gradient dMRI was performed to access a series of diffusion times and b-values, and the data were fitted with the IMPULSED model to estimate cell diameter, intracellular fraction, and diffusivity metrics. In a pilot study of 17 pediatric brain tumor patients, all high-grade tumors showed higher intracellular fraction and cellularity than the low-grade ones, while the cell diameter showed differentiation among different types of high-grade tumors. 

Joshua S. Greer^1,2, Daniel A. Castellanos¹, Yousef Arar¹, Surendranath R. Veeram Reddy¹, Yin Xi², Gerald F. Greil^1,2,3, Ananth J. Madhuranthakam^2,3, and Tarique Hussain^1,2
1Pediatrics, UT Southwestern Medical Center, Dallas, TX, United States, ²Radiology, UT Southwestern Medical Center, Dallas, TX, United States, ³Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States

In this study, a recently proposed MRI blood oximetry technique was optimized to improve the accuracy of oxygen saturation measurements. Simulations of the Luz-Meiboom model were performed to optimize the T₂-prep refocusing intervals and to guide the selection of the blood pool used for nuisance parameter estimation. Blood oxygen saturation measurements were validated against MR-guided cardiac catheterization under the same anesthetic conditions in patients with congenital heart disease, with the proposed O₂ mapping technique demonstrating improved agreement with blood gas analysis. The proposed improvements may allow for future examination of blood pool oxygenation without the need for invasive cardiac catheterization.

Jan W Kurzawski^1,2, Matteo Cencini^1,3, Laura Biagi^1,4, Graziella Donatelli^1,5, Rosa Pasquariello⁴, Roberta Battini^3,4, Claudia Dosi^3,4, Chiara Ticci^3,4, Alessandra Retico², Guido Buonincontri^1,4, and Michela Tosetti^1,4
1Imago7, Pisa, Italy, ²INFN, Pisa, Italy, ³University of Pisa, Pisa, Italy, ⁴IRCCS Stella Maris, Pisa, Italy, ⁵Neuroradiology, Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy

New advancements in magnetic resonance fingerprinting (MRF) allow more accurate quantification of tissue characteristics and its components using multi-component dictionaries. Recently, a multi-component method for mapping Myelin-Water fraction (MWF) was suggested and validated in healthy children. Here, we studied a cohort with different disorders including hypo- or de- myelinization, Creatine Deficiency Syndrome and brain malformations. We reconstruct MWF maps using tailored dictionaries and estimate fractional myelin values in the splenium of corpus callosum. We observed that myelinization plateaus at around 30 months from birth, while in patients with white matter disorders the process is distorted.

Marilena M DeMayo¹, Ashley D Harris^2,3,4, Ian B Hickie⁵, and Adam J Guastella^1
1Brain and Mind Centre, Children's Hospital Westmead Clinical School, University of Sydney, Camperdown, Australia, ²Department of Radiology, University of Calgary, Calgary, AB, Canada, ³Hotchkiss Brain Institute, Calgary, AB, Canada, ⁴Alberta Children's Hospital Research Institute, Calgary, AB, Canada, ⁵Brain and Mind Centre, University of Sydney, Sydney, Australia

GABA, the mature brain’s primary inhibitory neurotransmitter, has been proposed to contribute to the development of Autism Spectrum Disorder (ASD) and the maintenance of ASD symptoms. Investigations have found reductions in GABA in children and adolescents with ASD. In the current study, GABA levels were measured using GABA-edited MEGA-PRESS in the left parietal lobe. The study compared 24 children with ASD and 35 typically developing (TD), aged 4-12 years. Increasing GABA concentration with age was found in the ASD participants but not in the TD cohort, suggesting a distinct pattern of GABA development in ASD within the parietal lobe.

Serge Vasylechko¹, Emer Hughes², Joanna Allsop², Matthew Fox², Daniel Rueckert¹, and Jo Hajnal^2
1Biomedical Image Analysis Group, Department of Computing, Imperial College London, London, United Kingdom, ²Centre for the Developing Brain, School of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom

Quantitative T2* mapping in the developing brain is challenging due to inherent motion of fetal and neonatal subjects. This study uses a motion robust framework for acquisition, reconstruction and segmentation of whole brain T2* maps. This is achieved by single-shot multi-echo GRE EPI acquisition, multi-level slice-to-volume registration and gestational-age specific brain atlas segmentation. T2* values are reported for fetal and neonatal subjects at 3T. Findings indicate large variability in T2* within each subject group, non-linear change in T2* between fetal and preterm neonatal period, and significantly higher mean T2* constants than previously reported in adult subjects.

Thomas A Roberts¹, Joshua FP van Amerom^1,2, Lucilio Cordero-Grande¹, Alena Uus¹, Anthony N Price¹, David FA Lloyd^1,3, Laurence H Jackson¹, Milou PM van Poppel¹, Kuberan Pushparajah³, Mary A Rutherford¹, Reza Rezavi^1,3, Maria Deprez¹, and Joseph V Hajnal^1
1School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom, ²Division of Pediatric Cardiology, The Hospital for Sick Children, Toronto, ON, Canada, ³Department of Congenital Heart Disease, Evelina Children's Hospital, London, United Kingdom

Measurement of blood flow in the fetal heart and the great vessels is challenging due to fetal motion and its small size. Previously, we demonstrated use of k-t SENSE real-time 2D imaging combined with slice-to-volume registration to reconstruct 4D velocity cine volumes. This required 50% of the examination to be spent acquiring training data. In this work we combine sliding window reconstruction of the under-sampled target data with some prior knowledge to dispense with training data altogether. We reconstruct 4D blood flow volumes in 5 fetal hearts using both methods and show that they are broadly equivalent.

Cristina Cudalbu¹, Lijing Xin¹, Bénédicte Maréchal^2,3,4, Tobias Kober^2,3,4, Sarah Lachat⁵, Nathalie Valenza⁶, Florence Zangas-Gehri⁶, and Valérie McLin^5
1Centre d'Imagerie Biomedicale, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, ²Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland, ³Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland, ⁴LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, ⁵Swiss Pediatric Liver Center, Department of Pediatrics, Gynecology and Obstetrics, University Hospitals Geneva, and University of Geneva Medical School, Geneva, Switzerland, ⁶Pediatric Neurology Unit, Department of Pediatrics, Gynecology and Obstetrics, University Hospitals Geneva, and University of Geneva Medical School, Geneva, Switzerland

Children with chronic liver disease (CLD) or congenital portosystemic shunts (CPSS) show neurocognitive deficits that are not entirely reversible following liver transplantation or shunt closure. We measured for the first time the neurometabolic profile, brain volumetry and T1 relaxation times of children with CLD and CPSS at 7T. In patients with compensated CLD, there were no significant neurometabolic alterations as assessed by 1H-MRS, while small changes in amygdala and hippocampus volumes were measured. In CPSS, however, neurometabolic changes were pronounced, together with a marked decrease in all measured brain volumes, and likely related to measurably impaired neurocognitive functioning.

Borjan Gagoski^1,2, Junshen Xu³, Paul Wighton⁴, Dylan Tisdall⁵, Robert Frost^2,4, Sayeri Lala⁶, Wei-Ching Lo⁷, Polina Golland^8,9, Andre van der Kouwe^2,4, Elfar Adalsteinsson^8,10, and P. Ellen Grant^1,2
1Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Boston, MA, United States, ²Department of Radiology, Harvard Medical School, Boston, MA, United States, ³(co-first author) Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, ⁴Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, ⁵Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States, ⁶Department of Electrical Engineering, Princeton University, Princeton, NJ, United States, ⁷Siemens Medical Solutions USA, Inc, Charlestown, MA, United States, ⁸Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, ⁹Computer Science and Artificial Intelligence Laboratory (CSAIL), Massachusetts Institute of Technology, Cambridge, MA, United States, ¹⁰Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States

Fetal brain MRI suffers from unpredictable and unconstrained fetal motion that not only causes severe image artifacts even with single-shot FSE readouts, but also results in slice-to-slice variations of the imaging plane and long scanning sessions, as the MR technologist “chases” the fetal head in an attempt to acquire artifact-free orthogonal images. In this work, we have implemented a closed-loop pipeline that automatically detects and reacquires HASTE images that were degraded by fetal motion, without any interaction from the MRI technologist. The presented methods demonstrate the basic infrastructure needed for successful prospective automated fetal brain motion correction.

Maxime Chamberland¹, Sila Genc¹, Erika P Raven¹, Chantal M.W. Tax¹, Greg D Parker¹, Adam Cunningham², Joanne Doherty^1,2, Marianne van den Bree², and Derek K Jones^1
1CUBRIC, Cardiff University, Cardiff, United Kingdom, ²MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, United Kingdom

Most clinical diffusion MRI studies rely on the statistical comparison of a group of patients against a group of healthy controls to make inference about disease. This stymies the potential power of microstructural MRI in the clinic, i.e., to identify microstructural abnormalities in a single patient. We present a framework to address this problem on a case-by-case basis, extending the reach of microstructural imaging to rare cases, where group comparisons are otherwise impossible. Our framework operates on the manifold of white matter pathways and uses autoencoders to learn normative microstructural features, and discriminate patients from controls in a paediatric population.

Maria Yanez Lopez¹, Anthony N Price¹, Emer Hughes¹, Nicolaas AJ Puts^2,3, Richard AE Edden^2,3, Grainne McAlonan⁴, Tomoki Arichi^1,5, and Enrico De Vita^6
1Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, ²Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, MD, United States, ³F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, ⁴Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom, ⁵Department of Bioengineering, South Kensington Campus, Imperial College London, London, United Kingdom, ⁶Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom

We measured GABA, Glx and GSH levels in a population of healthy neonates, using HERMES at 3T. We show that HERMES can be used to measure significant regional differences (in this case between the thalamus and anterior cingulate cortex). Further application of this method to study how these levels and balance are altered by early-life brain injury or genetic risk can provide important new knowledge about the pathophysiology underlying neurodevelopmental disorders.