Ayse Sila Dokumaci^1,2, Katy Vecchiato^2,3,4, Raphael Tomi-Tricot^1,2,5, Pip Bridgen^1,2, Michael Eyre^1,2, Tobias C. Wood⁶, Chiara Casella^2,4, Jan Sedlacik^2,7, Tom Wilkinson^1,2, Sharon Giles^1,2, Joseph V. Hajnal^1,2, Shaihan Malik^1,2, Jonathan O’Muircheartaigh^2,3,4,8, and David W. Carmichael^1,2
1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, ²London Collaborative Ultra high field System (LoCUS), London, United Kingdom, ³Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom, ⁴Centre for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom, ⁵MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, ⁶Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom, ⁷Radiology Department, Great Ormond Street Hospital for Children, London, United Kingdom, ⁸MRC Centre for Neurodevelopmental Disorders, King’s College London, London, United Kingdom

The Magnetization Prepared 2 Rapid Acquisition Gradient Echoes (MP2RAGE) sequence is commonly used for 3D structural T₁-weighted imaging of the brain at 7T and can be optimised to obtain UNI and clinically relevant FLuid and White Matter Suppression (FLAWS) images within one acquisition. In this study, such a protocol was used together with newly derived analytical equations accounting for partial Fourier acquisitions, and B₁⁺ maps, in a dedicated fitting algorithm to produce quantitative T₁ and arbitrarily scaled PD-maps. These maps were evaluated in children and adults at 7T demonstrating a significant T₁ reduction with age.

Esra Sümer¹, Kübra Tan², Ayça Ersen Danyeli³, Ozge Can⁴, M. Necmettin Pamir⁵, Alp Dinçer⁶, Koray Özduman⁵, and Esin Ozturk-Isik^1
1Institute of Biomedical Engineering, Bogazici University, İstabul, Turkey, ²Health Institutes of Turkey, İstanbul, Turkey, ³Department of Medical Pathology, Acibadem Mehmet Ali Aydinlar University, İstanbul, Turkey, ⁴Department of Medical Engineering, Acibadem Mehmet Ali Aydinlar University, İstanbul, Turkey, ⁵Department of Neurosurgery, Acibadem Mehmet Ali Aydinlar University, İstanbul, Turkey, ⁶Department of Radiology, Acibadem Mehmet Ali Aydinlar University, İstanbul, Turkey

Meningioma is the most common primary intracranial tumor in adults, and loss of NF2 function in meningiomas has been associated with a more aggressive biology, shorter time to recurrence and shorter overall survival. In this work, radiomics based biomarkers of NF2 copy number loss (NF2-L) have been assessed. Lower grey-level co-occurrence matrix cluster shade with wavelet high-high-low pass filter, lower original image first order minimum, and higher first order skewness with wavelet low-low-high pass filter were observed in tumors with NF2-L compared to tumors with no copy number loss. The classification accuracy of NF2 molecular subsets was 0.80±0.03 (precision=0.85±0.04, recall=0.73±0.05).

Kaiming Li¹ and Xiaoping Hu^1
1Department of Bioengineering, UC Riverside, Riverside, CA, United States

Framewise co-activity patterns of functional MRI data may reflect the transient synchronization and coordination across brain regions. High-intensity frames of resting state fMRI have revealed granulated co-activation patterns that resembled the resting state brain networks. However, whether the low-intensity frames carry such information remains unclear. The present study trained variational autoencoder models with both positive values and negative values of normalized fMRI time series respectively and evaluated the two models on a separate dataset. We found the two models were very similar, suggesting that the negative-value frames can reflect transient brain co-activity patterns as the positive ones do.

NING LI^1,2, Cyril Tous^1,2, Phillip Fei^1,2, Ivan P Dimov^1,2, Simon Lessard^1,2, Urs O. Häfeli³, Sylvain Martel⁴, An Tang^1,2, and Gilles Soulez^1,2
1Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montreal, QC, Canada, ²Université de Montréal, Montreal, QC, Canada, ³University of British Columbia, Vancouver, BC, Canada, ⁴Polytechnique Montréal, Montreal, QC, Canada

Magnetic steering of superparamagnetic drug-eluting particles (SMDEPs) loaded with anti-tumor drugs across hepatic arteries is a promising technique to perform segmental liver embolization for patients with hepatocellular carcinomas (HCCs). These aggregates (20 ± 6 SMDEPs) are sequentially released with a specially designed injector through a catheter in the proper hepatic artery of a swine placed in an MRI. Manual segmentation was previously done to localize and count the particles (volume of the artifact) in each lobe. We propose to train a U-net over this pre-existing database. Dice similarity coefficient, accuracy, and precision were respectively 99.1%, 98.3%, and 84.6%.

Yue Qin¹, Dayong Jin¹, Xin Li¹, Liyao Liu¹, Yinhu Zhu¹, Juan Tian¹, Yifan Qian¹, Shaoyu Wang², and Boyuan Jiang^1
1Xi'an Daxing Hospital, Xi'an, China, ²Siemens Healthineers, Ltd., Xi'an, China

This study investigated ZOOMit and RESOLVE DWI sequences to compare of the image quality of anal canal and the visibility of the fistula. The results showed that both ZOOMit DWI and RESOLVE DWI obtained high quality images， ZOOMit DWI sequence had higher fistula visibility and SNR of the fistula than those of RESOLVE DWI sequence. Our findings also suggest that ZOOMit DWI can be used as the preferred sequence for anal MR diffusion imaging.

Riona Fumi¹, Hanna Maksimuk^2,3, James H Cole^4,5, and Sjoerd B Vos^2,4,6
1Queen Square Institute of Neurology, University College London, London, United Kingdom, ²Neuroradiological Academic Unit, Queen Square Institute of Neurology, University College London, London, United Kingdom, ³Department of Radiology, Brest Regional Clinical Hospital, Brest, Belarus, ⁴Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom, ⁵Dementia Research Centre, Queen Square Institute of Neurology, University College London, London, United Kingdom, ⁶Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, Perth, Australia

Cortical T1/T2 ratios (T1/T2r) have been used to assess myelination along the lifespan and investigate demyelination in neurological diseases. Creating a comprehensive normative population from open-access datasets could facilitate widespread adoption of this technique. Here we investigate comparability between two such publicly available datasets, OASIS3 and CamCAN. We find that they vary in terms of offset, lifespan trajectory, and presence (OASIS3) or absence (CamCAN) of hemispheric asymmetry. This variability exists despite both studies use the same scanner model, and is likely increased across different scanner models and vendors. These findings indicate that combining data from different studies requires advanced normalisation.

Seema S Bhat¹, Pavan Poojar^2,3, Chennagiri Rajarao Padma², and Hanumantharaju MC^4
1Department of Information Science and Engineering, Dayananda Sagar College of Engineering, Bengaluru, India, ²Department of Medical Electronics, Dayananda Sagar College of Engineering, Bengaluru, India, ³Columbia University in the City of New York, Newyork, NY, NY, United States, ⁴Department of Electronics and Communications, BMS Institute of Technology and Management, Bangalore, India

Denoising is an alternative for enhancing signal-to-noise ratio in high b-value diffusion imaging instead of prolonged acquisition time. We experimented   a deep learning based denoising method on prospective high b-value DWI and visualized the impact of denoising using fractional anisotropy(FA) maps. Experiment was repeated for three different signal averages:1,2 4-NEX  and two different slice thickness 1mm and 5mm with gold standard reference of 10-NEX images. The current work obtained average peak signal-to-noise ratio >34dB and  SSIM >0.94 after denoising for FA maps. The PSNR and SSIM values in FA maps were modestly increased after denoising.

Hendrik Mattern¹ and Oliver Speck^1,2,3,4
1Biomedical Magnetic Resonance, Otto von Guericke University, Magdeburg, Germany, ²German Center for Neurodegenerative Disease, Magdeburg, Germany, ³Center for Behavioral Brain Sciences, Magdeburg, Germany, ⁴Leibniz Institute for Neurobiology, Magdeburg, Germany

The detection of vessel in MRI depends on the imaging resolution used. Hence, subsequent quantification with vessel densities and vessel distance mapping (VDM) is resolution dependent. In this study, the resolution dependency of both metrics was evaluated for arteries and veins in deep gray matter regions by retrospective downsampling of high-resolution vessel images. Quantitative comparison shows that with decreasing resolution the estimated vessel distances increase, while vessel densities decline. The resolution dependency of vessel densities and distances can be modeled linearly. The here found scaling factors may improve inter-study comparability of vessel densities and VDM.

Xin Li¹, Yue Qin¹, Dayong Jin¹, Yinhu Zhu¹, Liyao Liu¹, Yifan Qian¹, Juan Tian¹, and Shaoyu Wang^2
1Xi'an Daxing Hospital, Xi'an, China, ²Siemens Healthineers, Ltd., Xi'an, China

This study used magnetic resonance cholangiopancreatography (MRCP) to compare the image quality and acquisition time of conventional respiratory-triggered (RT), modified RT, and breath-hold (BH) sampling perfection with application-optimized contrasts using different flip evolutions (SPACE) sequences in patients with biliary and pancreatic disorders. Our results suggested that modified RT-SPACE-MRCP sequence can significantly reduced acquisition time and had better image quality. The MRCP sequence can be selected flexibly according to the patient's situation to obtain good diagnostic images.

Jeffry R Alger^1,2,3,4, Maylen Perez Diaz⁵, Joseph O'Neill⁵, Dara Ghahremani⁵, Andy C Dean⁵, Sulaiman Sheriff⁶, Andrew A Maudsley⁶, and Edythe London^5
1NeuroSpectroScopics LLC, Sherman Oaks, CA, United States, ²University of California, Los Angeles, Los Angeles, CA, United States, ³Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States, ⁴Hura Imaging Inc, Calabasas, CA, United States, ⁵Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States, ⁶Radiology, University of Miami, Miami, FL, United States

Spectral averaging of thousands of magnetic resonance spectroscopic imaging voxel spectra over large brain volumes provides a means of assessing low-level and/or hard-to-quantify metabolite differences over large brain volumes between groups of individuals.

Renzo Torrecuso¹, Karsten Mueller¹, Stefan Holiga^1,2, Dusan Urgosik³, Josef Vymazal⁴, Tomas Sieger⁵, Filip Růžička⁶, Evzen Růžička⁷, Matthias Schroeter⁸, Robert Jech³, and Harald E. Möller^1
1NMR, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ²Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland, ³Department of Neurology, Charles University in Prague | CUNI, Prague, Czech Republic, ⁴| CULS · Faculty of Environmental Science, Czech University of Life Sciences Prague, Prague, Czech Republic, ⁵Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, Prague, Czech Republic, ⁶Department of Environmental Engineering, Faculty of Technology Tomas Bata University in Zlín, Zlin, Czech Republic, ⁷Neurology, General University Hospital in Prague, Prague, Czech Republic, ⁸Clinic for Cognitive Neurology, University Hospital Leipzig, Leipzig, Germany

Foreseeing how specific brain areas respond in time to a stimulus can be a prerequisite for a successfully conceived fMRI experiment. We demonstrate that in medicated Parkinson’s disease patients, putamen's activation peaks around the onset of tapping but does not persist throughout the tapping block, whereas sustained activation is observed in the motor cortex. Consequently, in the widely used tapping paradigm “On vs. Off L-DOPA”, the drug effect remains undetected if statistical analysis apply a block design  instead of an event-related one. Ignoring this information can lead to  fallacious conclusions which suggests using different models to investigate different brain regions.

Rick J. van Tuijl¹, Stanley D.T. Pham¹, Birgitta K Velthuis¹, Ynte M. Ruigrok², Geert Jan Biessels², and Jaco J.M. Zwanenburg^1
1Radiology, UMC Utrecht, Utrecht, Netherlands, ²Neurology, UMC Utrecht, Utrecht, Netherlands

We studied the test-retest reliability of assessing perforating arteries of the BG with 2D-PC velocity measurements at 3T-MRI, with and without repositioning of the patient. We showed reproducible assessment of N_detected, V_mean and vPI in the perforating arteries, independent of slice planning. The relative imprecision was smallest for V_mean (12%) and highest for vPI (32%). The interrater-reliability assessment showed high consistency between two raters (mean variability <5% for all parameters). We found very similar Limits of Agreement with and without repositioning, which indicated that uncertainty in measuring these parameters was dominated by scanner and physiological noise, rather than by planning.
 

Yogesh Rathi¹, Lipeng Ning¹, Congyu Liao², Yang Ji³, Carl-Fredrik Westin¹, Fan Zhang¹, Nikolaos Makris¹, Lauren J O'Donnell¹, and Kawin Setsompop^2
1Harvard Medical School, Boston, MA, United States, ²Stanford University, Stanford, CA, United States, ³Oxford University, Oxford, United Kingdom

Tractography is typically obtained from diffusion MRI data acquired at a particular echo time (TE). Recent works have shown differential T2-relaxation times of tissue microstructure and fiber tracts. However, estimation of T2 in fiber bundles have typically been done at the last stage (after tractography). In this work, we show that tractography itself is affected by the T2 (and hence TE) of the fibers. Specifically, we show that the ability to trace accurately depends on the T2 of the fiber bundle. This is specifically true for the superficial white matter (u-fibers) which has higher myelination and iron content.

Stefan Winzeck^1,2, Sophie Richter², Maira Siqueira Pinto³, Evgenios N. Kornaropoulos⁴, Virginia F.J. Newcombe², Ben Glocker¹, David K. Menon², and Marta M. Correia^5
1BioMedIA, Department of Computing, Imperial College London, London, United Kingdom, ²University Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, United Kingdom, ³Universitair Ziekenhuis Antwerpen, Antwerp, Belgium, ⁴Clinical Sciences, Lund, Diagnostic Radiology, Lund University, Lund, Sweden, ⁵MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, United Kingdom

The comparison of voxel-wise regression analysis of a multi-centre diffusion MRI study showed that similar results could be achieved regardless of whether prior data harmonisation was applied or not. However, harmonisation had a positive impact on increasing the effect size found between mild traumatic brain injury patients and controls.

Kaue Tartarotti Nepomuceno Duarte¹, Richard Frayne¹, David Gobbi², Paulo Sergio Martins³, and Marco Antonio Garcia de Carvalho^3
1Radiology, University of Calgary, Calgary, AB, Canada, ²CIPAC, University of Calgary, CALGARY, AB, Canada, ³University of Campinas, Limeira, Brazil

Alzheimer's Disease is one of the most prevalent types of dementia that affects human behaviour and cognitive skills. The progression of this dementia occurs at different rates in distinct parts of the brain, thus also affecting their brain shape. We proposed an approach based on shape feature extraction and image ranking to identify which regions are more predictive for each level of the AD progression. For each stage, we highlighted the sub-cortical regions that suggested a strong correlation in the AD levels. In fact, the results showed a predictive pattern, which aligns to the state-of-the-art.