Masaaki Hori^1,2, Kouhei Kamiya^1,2,3, Akifumi Hagiwara², Kazumasa Yokoyama⁴, Issei Fukunaga⁵, Sano Katsuhiro², Koji Kamagata², Murata Katsutoshi⁶, Shohei Fujita², Christina Andica², Akihiko Wada², Julien Cohen-Adad⁷, and Shigeki Aoki^2
1Radiology, Toho University Omori Medical Center, Tokyo, Japan, ²Radiology, Faculty of Medicine, Juntendo University, Tokyo, Japan, ³Radiology, Tokyo University, Tokyo, Japan, ⁴Neurology, Faculty of Medicine, Juntendo University, Tokyo, Japan, ⁵Radiological Technology,, Faculty of Health Science, Juntendo University, Tokyo, Japan, ⁶Siemens Japan K.K., Tokyo, Japan, ⁷NeuroPoly Lab, Polytechnique Montreal, Montreal, QC, Canada

We investigated the microstructural changes in the spinal cords of patients with multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) using micro fractional anisotropy (μFA) derived from both double diffusion encoding (DDE) and 2-shell single diffusion encoding data with spherical mean techniques (SMT). There was no significant difference in μFA between MS and NMO. SMTs were not correlated with μFA derived from DDE. Therefore, SMT may be better treated as a separate diffusion MRI metric from μFA to investigate the microstructural alterations of spinal cord in patients with MS and NMOSD in vivo.

Cindy xue^1,2, Jing Yuan¹, Yihang Zhou¹, Oilei Wong¹, Kin Yin Cheung³, and Siu Ki Yu^3
1Research Department, Hong Kong Sanatorium and Hospital, Hong Kong, Hong Kong, ²Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong, Hong Kong, ³Medical Physics Department, Hong Kong Sanatorium and Hospital, Hong Kong, Hong Kong

Radiomics has been increasingly used as potential quantitative imaging biomarkers for head and neck cancer diagnosis and treatment. However, the test-retest repeatability of radiomics features in the head and neck (HN) region is rarely investigated. This study aims to investigate the test-retest repeatability of MRI radiomics features in HN. Radiomics features were extracted from 15 volunteers receiving 4 re-positioned MRI scans with thermoplastic mask immobilization and flexible coils using 3D-T1w-TSE and 3D-T2w-TSE. The results found that test-retest repeatability of MRI radiomics features varied dependent on tissues and pulse sequences. Only a small percentage of radiomics features showed excellent test-retest repeatability.

Chunxiang Jiang^1,2,3, Marco Bigica³, Ilenia D’Onofrio³, Zhishan Liu³, Lijuan Zhang¹, and Chen Song^3,4
1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ²University of Chinese Academy of Sciences, Beijing, China, ³Cardiff University Brain Research Imaging Centre, Cardiff, United Kingdom, ⁴University of Wisconsin-Madison, Madison, WI, United States

We examined the effect of sleep deprivation (SD) on human brain white matter（WM） using advanced fixel-based analysis. MRI data collected at four morning time points (7-8am, before and after SD, one night recovery and 3 days recovery). Compared to the session before SD, several WM tracts involving in sleep and wakefulness regulation, memory consolidation and emotion response showed varied fiber density (FD), fiber cross-section (FC) and the combined measure of FD and FC (termed FDC) at different time points. These findings demonstrated the heterogeneous sensitivity of WM tracts in response to SD and the microstructural homeostasis.

Congcong Liu¹, Miaomiao Wang¹, Xianjun Li¹, Yao Ge¹, and Jian Yang^1
1the Department of Radiology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China

Characterizing development trajectories of white matter (WM) is vital for identifying causes of neurodevelopmental disorders. Besides DKI, MRE depicted mechanical properties of brain as a sensitive technique. But WM development trajectories of children were lack of researches on MRE. Therefore, we aimed to investigate age-related development of WM based on virtual elastography, comparing with DKI. We found virtual shear stiffness of WM was positively correlated with age, particularly presenting rapid-growth period of WM before 4-years old, consistent with changes of MK, FA. Virtual elastography may be potentially a valuable technique for depicting WM development trajectories, complementary to diffusion metrics.

Sang-Jin Im¹, Ji-Yeon Suh¹, Jae hyuk Shim¹, and Hyeon-Man Baek^1
1Lee Gil Ya Cancer and Diabetes Institute, Incheon, Korea, Republic of

Unlike image analysis studies with human subjects, where various programs have been developed and validated to provide a complete assessment and step-by-step work procedure, methods for analyzing image data using MRI in preclinical research settings have not been agreed upon. Therefore, in this study, for the high-accuracy SIGMA atlas, we present a deterministic tractographic analysis pipeline that can perform detailed structural segmentation of the rat brain and confirm structural connectivity based on the segmented regions.

Yuichi Suzuki¹, Shinya Yuki², Tsuyoshi Ueyama¹, Kentaro Sakata¹, Takahiro Iwasaki¹, Nobuhito Saito², Hideyuki Iwanaga¹, and Osamu Abe^1,3
1Radiology Center, The University oh Tokyo Hospital, Tokyo, Japan, ²Department of Neurosurgery, The University oh Tokyo Hospital, Tokyo, Japan, ³Department of Radiology, The University oh Tokyo Hospital, Tokyo, Japan

There are no reports on the use of TractSeg in patients with brain arteriovenous malformations (BAVMs). This study aimed to investigate the effect of the presence of BAVMs on TractSeg findings of the corticospinal tract (CST) and their clinical usefulness. In case of BAVMs through which the CST runs, the visualization was affected, but in most cases, tractography reconstruction was possible. In case of BAVMs through which the CST does not run, the same results as that of normal volunteers were obtained.

Kaili Liang¹, Ruohan Feng¹, Xuan Bu¹, Suming Zhang¹, Yingxue Gao¹, Weijie Bao¹, Lingxiao Cao¹, Jing Liu¹, Hailong Li¹, Lianqing Zhang¹, and Xiaoqi Huang^1
1Huaxi MR Research Center (HMRRC), Functional and molecular imaging Key Laboratory of Sichuan Province, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China

We aimed to measure diffusion parameters along the uncinate fasciculus and examine the specific and focal alterations of the uncinate fasciculus in first-episode and drug-naïve patients with major depressive disorder in adolescents by using a tract-based quantitative technique. Notably, we found the opposite alterations of the diffusion metrics in the insular and frontal segments of left uncinate fasciculus  in adolescents with depression. It will help us to better understand the neurobiological mechanisms of adolescent depression and optimize adolescent-specific treatments for depression.

Mai Phuong Ho¹, Fernando Calamante^1,2,3, and Jinglei Lv^1,2
1School of Biomedical Engineering, University of Sydney, Sydney, Australia, ²Brain and Mind Centre, University of Sydney, Sydney, Australia, ³Sydney Imaging, University of Sydney, Sydney, Australia

To compare white matter fibre tracks between individuals or within the same individual over time, a diffusion MRI tractography template is essential. Tractography template describes the location and orientation of fibre bundles that build a representative organization of human white matter. Despite numerous recent advances in methods to map human brain connectivity, tractography suffers from several limitations, including the over- and the under-representation of certain fibre populations. By integrating multimodal registration and SIFT2 quantification approach, we explore the most consistent bundles across subjects, which could help us advance our understanding of the common wiring in the human brain.

Tao Gong^1,2, Guoquan Huang³, Liangjie Lin⁴, and Guangbin Wang^1
1Departments of Radiology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, 250021, China, Jinan, China, ²Departments of Radiology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250021, China, Jinan, China, ³Department of Radiology, Wuhu City Second People's Hospital, No. 259 Jiuhua Rd, Wuhu, 241000, Anhui, China., Wuhu, China, ⁴MSC Clinical & Technical Solutions, Philips Healthcare, Beijing, China., Beijing, China

More evidences have been identified that pudendal nerve was involved in the pathogenesis of erectile dysfunction (ED) in young men. This prospective study aimed to detect and quantify pudendal nerve alterations in young men with ED using 3T MR neurography protocol. Results certified that pudendal nerve could be visualized and quantified. T2 signal contrast ratio and nerve diameter of pudendal nerve  were increased significantly in ED patients compared with healthy controls, suggesting the involvement of pudendal nerve in young men with ED and thus offering a new insight into the pathophysiology and treatment of ED.

Yueyao Chen¹, Zhongxian Pan¹, Fanqi Meng¹, Zhujing Li¹, Jinyun Gao¹, Yuanming Hu¹, Yihao Guo², Qian Xu¹, Leyu Huang¹, and Hanqing Lv*^1
1Department of Radiology, Shenzhen Traditional Chinese Medicine Hospital (The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine), Shenzhen, China, ²MR Collaboration, Siemens Healthineers Ltd., Guangzhou, China

This study compared single-shot echo-planar imaging (SS-EPI) with readout-segmented echo-planar imaging (RS-EPI) diffusion tensor imaging (DTI) in vivo anesthetized rat sciatic nerve at 3T. The result showed that the image quality scores of SS-EPI were higher than those of RS-EPI in terms of the nerve morphology and homogeneity of the neuromuscular region. The coefficients of FA and RD obtained with SS-EPI were higher than those obtained with RS-EPI SS-EPI. This suggests that in rat sciatic nerve DTI, SS-EPI showed higher image quality and offered more sensitive and stable parameters to detect the histopathological change in the rat sciatic nerve.

Caijuan Zhang¹, Dong Dong¹, Shiyu Guo¹, Lishan Wu¹, Yi Zhu², and Ke Jiang^2
1Radiology, First Hospital of Jilin University, changchun, China, ²Philips Heathcare, Beijing, China

High resolution three dimensional (3D) sequences of MR Neurography always takes a very long scan time. However, using very high acceleration factors leads to degradation of image quality due to insufficient noise removal. In this study, we used Compressed-SENSE Artificial Intelligence (CS-AI) framework to acquire highly accelerated 3D NerveView imaging of lumbosacral plexus. The result showed that CS-AI reconstruction can significantly decrease scan time with sufficient image quality compared to Compressed SENSE(CS) and might be clinically useful in assessment of lumbosacral plexus.

Caijuan Zhang¹, Dong Dong¹, Shiyu Guo¹, Lishan Wu¹, Yi Zhu², Ke Jiang², and Wenxin Wang^2
1Radiology, First Hospital of Jilin University, changchun, China, ²Philips Heathcare, Beijing, China

Three-dimensional (3D) T2 Fast Field Echo (FFE) sequence of MR Neurography always takes a very long scan time. However, using very high acceleration factors (AF) will result in degradation of image quality due to insufficient noise removal. In this study, we used Compressed-SENSE Artificial Intelligence (CS-AI) framework to acquire highly accelerated T2 FFE imaging in lumbosacral plexus. The results showed that CS-AI reconstruction might significantly decrease scan time with sufficient image quality compared with conventional SENSE, and might be clinically useful for assessment of lumbosacral plexus.

Dan Bao¹, Yanfeng Zhao¹, and Dehong Luo^2
1Department of Radiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer, Beijing, China, ²National Cancer Center/National Clinical Research Center for Cancer/Cancer, Beijing, China

In order to early identify and predict RTLI after IMRT in patients with NPC, we developed and validated a radiomics model based on pretreatment MRI of temporal lobe. The radiomics model demonstrated excellent predictive performance in the validation set (AUC, 0.93; sensitivity, 87%; specificity, 97%). The clinical-radiomics nomogram outperformed clinical nomogram, and showed excellent predictive performance of RTLI in patients within different clinical-pathologic subgroups. These findings suggest that the identified radiomics signature has the potential as a biomarker for risk stratification in RTLI, which may potentially improve the quality of life and prognosis in NPC patients.

Qiaoling Wu¹ and Geli Hu^2
1Department of Radiology, Peking Union Medical College Hospital,Chinese Academy of Medical Sciences, Beijing, China, ²Philips Healthcare, Beijing, China

High resolution inner ear MR imaging plays an important role for preoperative plan of hearing system, such as cochlear implant surgery etc. Nowadays, 3D balanced fast-field echo sequence (3D b-FFE) is an effective technique to deliver high-resolution images up to a spatial resolution 0.5 0.5 0.5mm. However, black banding artifacts are frequently observed in the images of inner ear anatomic structures at 3.0T due to magnetic field inhomogeneity. In this study, the 3D b-FFE-XD technique which combines a cycling RF phase with the conventional b-FFE sequence to suppress the banding artifacts and improve the image quality.