Hyungseok Jang¹, Zhao Wei¹, Mei Wu¹, Yajun Ma¹, Eric Chang^1,2, Jody Corey-Bloom¹, and Jiang Du^1
1University of California, San Diego, San Diego, CA, United States, ²VA San Diego Healthcare System, San Diego, CA, United States

Myelin accelerates neural signaling in the central and peripheral nervous systems. Ultrashort echo time (UTE)-based imaging techniques have been proposed for direct capture of magnetic resonance (MR) signal from myelin lipid protons with extremely short T2* (~0.3 ms). To suppress signal from long T2 water components and thereby improve myelin imaging, inversion recovery (IR)-based UTE techniques have been proposed. In this study, we explored the efficacy and feasibility of qualitative myelin imaging in vivo combining dual-echo IR-UTE with complex echo subtraction.

Choong Heon Lee¹, Jing Li², Yulin Ge¹, Timothy M Shepherd¹, Youssef Zaim Wadghiri¹, Jiangyang Zhang¹, and David W Nauen^3
1Radiology, New York University School of Medicine, New York, NY, United States, ²Peking Union Medical College Hospital, Beijing, China, ³Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States

High-resolution diffusion MRI data of post-mortem adult human hippocampus specimens were acquired and compared to histology to identify major axonal pathways in the hippocampus. The complex microstructural organization in the hippocampus made it difficult to resolve axonal pathways based on conventional diffusion tensor data. In comparison, neurite density map using the NODDI toolbox revealed the locations of the perforant path, mossy fibers, and Schaffer collaterals confirmed by histology. We were able to reconstruct the fimbria/alveus and perforant pathways using tractography, and the results resembled in vivo results from the HCP dataset. Other pathways in the hippocampus remained difficult to delineate.

Xiaoxiao Qi¹, Yingjuan Wu¹, Abdur Raquib Ridwan¹, Shengwei Zhang¹, Mohammad Rakeen Niaz¹, and Konstantinos Arfanakis^1,2
1Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States, ²Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, United States

Group-wise spatial normalization of fiber orientation distribution functions (fODF) is an important step in fixel-based analysis. This work compared the accuracy in matching fODFs using fODF-based and tensor-based registration. It demonstrated superior fODF matching with fODF-based registration, as expected, even in conditions that are optimal for tensor but not fODF reconstruction. Nevertheless, it was shown that tensor-based registration has the ability to spatially match fODF features rather well, though less accurately than fODF-based registration. Finally, this work demonstrated that fODF-based transformations resulted in worse matching of structural information than tensor-based transformations.

Yumeng Cheng^1,2,3, Hongbin Han^1,2,3, Yajuan Gao^2,3, Rui Wang^2,3, Yu Song³, Xianjie Cai^1,2,3, and Zeqing Tang^1,2,3
1Institute of Medical Technology(IMT), Peking University Health Science Center(PKUHSC), Beijing, China, ²Department of Radiology, Peking University Third Hospital, Beijing, China, ³Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China

We proposed a simple quantitative method based on the linear relationship between MR signal enhancement and Gd-DTPA concentration (C) by using T1 3D MP-RAGE for the real-time in vivo measurement of Gd-DTPA concentration in neuroimaging at 3.0 T. A good linear relationship between ΔSI and Gd-DTPA concentration existed over the concentration range of 0–1 mM (R2=0.985). Further, six human subjects with different brain tumors were enrolled for in vivo application of the novel method. All the results revealed that the quantitative method presented by our study is accurate, real-time and applicable.

Yuki Matsumoto¹, Masafumi Harada¹, Yuki Kanazawa¹, Takashi Abe¹, Maki Otomo¹, Yo Taniguchi², Masaharu Ono³, and Yoshitaka Bito^3
1Tokushima University, Tokushima, Japan, ²Research & Development Group, Hitachi, Ltd., Tokyo, Japan, ³Healthcare Business Unit, Hitachi, Ltd., Tokyo, Japan

Concentration of contrast agent (CM), relaxivity (r1), extracellular pH (pHe), and oxygen extraction fraction (OEF), maps were calculated for detecting changes in tissue environment of brain diseases. As a result, the pHe value on glioblastoma or brain metastasis region was significantly lower than that on radiation necrosis (see Fig.3; P < 0.001). The OEF value on glioblastoma region recorded significantly lower values than radiation necrosis and lung metastasis (P < 0.001) while there was no significant difference amongst glioblastoma, breast metastasis, and lung metastasis (P > 0.05).

Samantha Cote¹, Jean-Francois Lepage², and Kevin Whittingstall^3
1Médecine Nucléaire et Radiobiologie, Université de Sherbrooke, Sherbrooke, QC, Canada, ²Pédiatrie, Université de Sherbrooke, Sherbrooke, QC, Canada, ³Radiologie Diagnostique, Université de Sherbrooke, Sherbrooke, QC, Canada

Standardized artery territorial distributions (ATD) are derived from variable post-mortem ATD yet assume a homogenous distribution.  We developed a downloadable probabilistic territorial distribution of the left-MCA derived from Time-of-Flight Magnetic-Resonance-Angiography that can be used with other MRI modalities. We examined the probability of the arterial territory in Broca’s and Wernicke’s area and found it to be almost 3 times higher in Broca area than Wernicke’s area; however, both are traditionally believed to be supplied by the left-MCA. Combining the variability of arterial territories with functionally defined regions of interest can advance our knowledge of the consequences of cerebrovascular incidents.

N. Jon Shah^1,2,3, Zaheer Abbas¹, Dominik Ridder¹, Markus Zimmermann¹, and Ana-Maria Oros-Peusquens^1
1Medical Imaging Physics, Institute of Neuroscience and Medicine 4, Jülich, Germany, ²Institute of Neuroscience and Medicine 11, INM 11, JARA, Jülich, Germany, ³Department of Neurology, Faculty of Medicine, Aachen, Germany

Measurement of quantitative, tissue-specific MR properties such as water content or relaxation times using quantitative-MRI at clinical field strength is a well-explored topic. However, none of the commonly used standard brain atlases, e.g., MNI or JHU, provide quantitative information. Utilising the framework of quantitative-MRI of the brain, this work reports on the development of the first quantitative in-vivo water content atlas based on twenty healthy volunteers datasets. Additionally, water content maps from patients with pathological changes in the brain were compared voxel-wise. These results suggest that quantitative-MRI in combination with water content atlas allows careful and quantitative interpretation of disease.

Koichi Oshio¹, Masao Yui², Seiko Shimizu², and Shinya Yamada^3,4
1Department of Diagnostic Radiology, Keio University School of Medicine, Tokyo, Japan, ²Canon Medical Systems Corporation, Otawara-shi, Japan, ³Kugayama Hospital, Tokyo, Japan, ⁴Juntendo University, Tokyo, Japan

Although there is no lymphatic system in the CNS, there seems to be a mechanism to remove macro molecules from the brain. CSF and ISF are thought to be parts of this pathway, but the details are not known. In this study, MR signal of the extracellular water, including CSF, was decomposed into components with distinct T2’s, to estimate content of macromolecules in each compartment. Assuming that protein content is relatively high along the clearance pathway, it might be possible to have some insight about this pathway from the obtained T2 map.

E. Brian Welch¹, Samantha By¹, Gang Chen¹, Hadrien Dyvorne¹, Cedric Hugon¹, Christopher McNulty¹, Anne Nelson¹, Rafael O'Halloran¹, Michael Poole¹, Laura Sacolick¹, Nicholas Zwart¹, Sean C.L. Deoni², Joel M. Stein³, Christopher Raio⁴, Kimon Bekelis⁵, Gerardo Chiricolo⁶, Kevin N. Sheth⁷, and Jonathan M. Rothberg^1
1Hyperfine, Guilford, CT, United States, ²Advanced Baby Imaging Lab, Brown University School of Engineering, Providence, RI, United States, ³Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA, United States, ⁴Emergency Department, Good Samaritan Hospital Medical Center, West Islip, NY, United States, ⁵Department of Neurological Surgery, Good Samaritan Hospital Medical Center, West Islip, NY, United States, ⁶Department of Emergency Medicine, New York Presbyterian Brooklyn Methodist Hospital, Brooklyn, NY, United States, ⁷Department of Neurology, Yale University School of Medicine, New Haven, CT, United States

Using the world’s first truly portable point-of-care (POC) MRI scanner, it is possible to acquire the fundamental neuro MR imaging contrasts in settings such as the neuro intensive care unit, emergency department, outpatient clinic, and pediatric clinic. Results are presented of neuro MRI exams of children and adults (some with known pathology) using T1W, T2W, FLAIR, and DWI from a low-field portable MRI scanner that transports directly to the patient’s bedside.