Roya Afshari^1,2, Francesco Santini^1,2, Rahel Heule^3,4, Craig Meyer⁵, Josef Pfeuffer⁶, and Oliver Bieri^1,2
1Department of Radiology, Division of Radiological Physics, University Hospital Basel, Basel, Switzerland, ²Department of Biomedical Engineering, University of Basel, Basel, Switzerland, ³Department of High Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, ⁴Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany, ⁵Department of Biomedical Engineering, University of Virginia, Virginia, VA, United States, ⁶Department of Application Development, Siemens Healthcare, Erlangen, Germany

To develop a rapid quantitative magnetization transfer (qMT) imaging methodology that offers whole brain coverage and takes into account B₁-field inhomogeneities for improved parameter estimation accuracy in the clinical setting.

Jing Cui¹, Yu Zhao¹, Feng Wang¹, Junzhong Xu¹, Daniel Gochberg¹, John Gore¹, and Zhongliang Zu^1
1Vanderbilt University Medical Center, Nashville, TN, United States

We evaluated the contribution of blood to the NOE(-1.6) from rat brains by using two blood suppression approaches: (1) signal acquisition with a diffusion-weighting of b=400s/mm²; (2) intravascular injection of 5mg/kg MION, and by measurements on an ex vivo blood sample. Results show that the NOE(-1.6) does not change significantly with diffusion weighting and is relatively weaker in ex vivo blood than that in brain, but decreases significantly in vivo after injection of MION. This study suggests that NOE(-1.6) is not mainly from blood, and that MION particles alter the NOE(-1.6) but have much weaker effects on other CEST effects.

Maryam Mozaffari^1,2, Nivin Nystrom^1,2, Alex Li¹, Miranda Bellyou¹, Timothy Scholl^1,2, and Robert Bartha^1,2
1Robarts Research Institute, London, ON, Canada, ²Department of Medical Biophysics, Western University, London, ON, Canada

The results of this study suggest the non-invasive assessment of tissue pH may provide value for monitoring the progression of diseases such as brain cancer that involve pH modification. This study also demonstrates that tissue acidification in a rat C6 glioma model and in contralateral tissue can be measured following drug injection by endogenous pH-weighted contrast produced by CEST-MRI. It is noteworthy that drugs like cariporide can acidify tumours and normal tissue. However, such drugs could enhance the efficacy of existing standard treatments in different human malignancies.

Xingwang Yong¹, Shanshan Lu², Yi-Cheng Hsu³, Yi Sun³, Dan Wu¹, and Yi Zhang^1
1Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China, ²The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China, ³MR Collaboration, Siemens Healthcare Ltd., Shanghai, China

Amide proton transfer (APT) imaging can detect pH-related changes in ischemic stroke lesions. However, the widely-used magnetization transfer ratio asymmetry (MTR_asym) analysis method is susceptible to various contamination sources. Here we improved the previous extrapolated semisolid magnetization transfer reference (EMR) method by numerical fitting of the EMR signal (NEMR) in the modified Bloch-McConnel equation.  The proposed NEMR method was compared with the previous EMR method in Monte Carlo simulations, demonstrating superior accuracy. Furthermore, the NEMR maps were compared with EMR and MTR_asym maps in nine ischemic stroke patients, yielding a better depiction of the ischemic lesions.

Alison R Roth¹, Jun Li², and Richard Dortch^1
1Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, United States, ²Neurology, Wayne State University, Detroit, MI, United States

Five magnetization transfer (MT) imaging metrics extracted from the sciatic nerve (magnetization transfer ratio (MTR), cross-sectional area (CSA), circularity, eccentricity, and nerve fascicle density) were assessed for their ability to act as imaging biomarkers in patients with inherited neuropathies.

Abigail T.J. Cember¹, Benjamin Deck², Jared Zimmerman³, Brian Erickson², Apoorva Kelkar², Olufunsho Faseyitan³, Mark Elliott¹, Ravinder Reddy¹, and John D. Medaglia^2
1Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Department of Psychology, Drexel University, Philadelphia, PA, United States, ³Laboratory for Cognition and Neural Stimulation, Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States

GluCEST was used to measure the effects of transcranial magnetic stimulation (TMS) to the motor cortex in healthy volunteers. Volunteers were scanned before and after stimulation or a sham, non-stimulating procedure. The data were analyzed by registering gluCEST maps to a cortical gray matter segmentation from Freesurfer and performing regional analysis. We find that this form of TMS, known as continuous theta-burst stimulation, had a consistent but non-local effect of decreasing the gluCEST signal in the brains of volunteers who received the stimulation in comparison to those who received a sham (placebo) procedure.

Patrick M. Lehmann¹, Mads Andersen², Anina Seidemo¹, Xiang Xu^3,4, Xu Li^4,5, Nirbhay Yadav^4,5, Ronnie Wirestam¹, Frederik Testud⁶, Patrick A. Liebig⁷, Pia C. Sundgren^8,9, Peter C. M. van Zijl^4,5, and Linda Knutsson^1,4
1Department of Medical Radiation Physics, Lund University, Lund, Sweden, ²Philips Healthcare, Copenhagen, Denmark, ³BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ⁴Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, ⁵F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, ⁶Siemens Healthcare AB, Malmö, Sweden, ⁷Siemens Healthcare GmbH, Erlangen, Germany, ⁸Department of Radiology, Lund University, Lund, Sweden, ⁹Lund University Bioimaging Centre, Lund University, Lund, Sweden

D-glucose was recently suggested as a CEST-based biodegradable alternative to gadolinium-based contrast agents. Dynamic glucose-enhanced (DGE) MRI can retrieve information about glucose uptake, determined by tissue perfusion, transport, and metabolism. Motion artefacts in DGE-MRI can be mistaken for CEST effects, while motion correction may erroneously alter true DGE signal. A digital human head phantom based on a realistic glucose infusion protocol was developed to analyse motion artefacts and validate rigid-head retrospective motion correction. This phantom can be used for testing different correction approaches using various motion patterns and contrast responses to better understand these effects in vivo.

Abigail T.J. Cember¹, Ravi Prakash Reddy Nanga¹, Hari Hariharan¹, Neil E. Wilson², Puneet Bagga³, and Ravinder Reddy^1
1Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Siemens Medical Solutions, USA, Malvern, PA, United States, ³Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, United States

We performed volumetric (3D) gluCEST with novel post-processing to image a slab containing the medial temporal lobe (MTL) in healthy human subjects. This data was segmented using a 7T atlas for hippocampal subfields. Upon further regional analysis, it was found that statistically significant differences exist between the mean gluCEST of MTL subfields; most prominently, that the dentate gyrus has greater gluCEST contrast than neighboring regions. We believe after some preliminary validation that this trend is independent of the B1 distribution or other variables. Moreover, it corroborates existing models of brain physiology identifying the DG as the locus of neurogenesis. 

Qingqing Wen¹, Kang Wang², Wenqi Wang¹, Yi Sun³, Dan Wu^1,2, and Yi Zhang^1,2
1Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China, ²Department of Neurology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China, ³MR Collaboration, Siemens Healthcare Ltd., Shanghai, China

  Chemical Exchange Saturation Transfer (CEST) imaging at 3T was applied to patients with temporal lobe epilepsy (TLE). Hippocampus and amygdala were automatically segmented, and then the magnetization transfer ratio asymmetry (MTR_asym), T₁, and T₂ values in these regions of interest were determined. It was found that MTR_asym in the hippocampus and amygdala was much more accurate than the quantitative T₁ and T₂ maps in predicting the seizure laterality, with an AUC value of 0.80 and a success rate of 17/20. The study indicated that CEST at 3T could potentially aid the clinical assessment of the epileptic foci in TLE patients.

Choong Heon Lee¹, Piotr Walczak², and Jiangyang Zhang^1
1Radiology, NYU Medical Center, New York, NY, United States, ²University of Maryland School of Medicine, Baltimore, MD, United States

Although multiple MRI techniques have been developed to detect and monitor myelin loss and repair, their sensitivity to myelin is often impaired by the underlying pathology. In this study, we demonstrate that inhomogeneous magnetization transfer (ihMT) can detect residual non-compact myelin in the context of hypercellular white matter in the dysmyelinating shiverer mouse model with optimized imaging parameters, whereas conventional MT show no apparent contrast. This result suggests that ihMT has higher sensitivity to myelin than conventional MT in the presence of cell infiltrations.

Xinying Ren¹, Yujing Li¹, Rui Wang¹, Tao Wen¹, Diaohan Xiong¹, Pengfei Wang¹, Guangyao Liu¹, Jing Zhang¹, and Kai Ai^2
1Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, China, ²Philips Healthcare, Xi'an, China

The study was to quantitatively analyze the peritumoral infiltration assisted gliomas grading by using amide proton transfer (APT) and dynamic contrast-enhanced imaging (DCE). Although many scholars use APT and DCE to help grading gliomas, but few of them pay attention to the peritumoral area. This research investigated the relationship between APT and DCE based K^trans value in peritumoral. The results show that these two parameters are significantly correlated. Therefore, the APT and K^trans value of peritumor edema in gliomas may be used to differentiate glioma grades, and APT value performs better in distinguishing grade Ⅱ and Ⅲ.

DiaoHan Xiong¹, Rui Wang¹, Tao Wen¹, Yujing Li¹, Xinying Ren¹, Pengfei Wang¹, Guangyao Liu¹, Jing Zhang¹, and Kai Ai^2
1Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, China, ²Philips Healthcare, Xi'an, China

We investigated the association of amide proton transfer weighted imaging (APTw) and 3D arterial spin label (3D-pCASL) with IDH1 Genotype and 1p/19q Status in gliomas，then compared the two methods. All patients underwent MR examination, including APT and 3D-pCASL scan to get their values of the solid part. The results showed both APTw and 3D-pCASL had predictive values on IDH1 Genotype and 1p/19q Status in gliomas, and the performance of 3D-pCASL was better. We conclude that both APTw and 3D-pCASL can be used to predict the gene type of IDHin high-grade and 1p/19q co-deletion of gliomas before surgery, meanwhile 3D-pCASL is the better choice.

Yasukage Takami¹, Naruhide Kimura¹, Katsuya Mitamura¹, Takashi Norikane¹, Keisuke Miyake², Tatsuya Yamasaki³, Kazuo Ogawa³, Mitsuharu Miyoshi⁴, and Yoshihiro Nishiyama^1
1Department of Radiology, Faculty of Medicine, Kagawa University, Miki-cho, Japan, ²Department of Neurological Surgery, Faculty of Medicine, Kagawa University, Miki-cho, Japan, ³Department of Clinical Radiology, Kagawa University Hospital, Miki-cho, Japan, ⁴Global MR Applications & Workflow, GE Healthcare Japan, Hino-shi, Japan

The purpose of this study was to evaluate the correlation between parameters on CEST imaging by multi pool model and ¹¹C-methionine (MET) uptake on PET/CT in gliomas. The maximum and mean values of the parameters on CEST imaging were measured. ¹¹C-MET uptake was semiquantitatively assessed using tumor-to-contralateral normal brain tissue (T/N) ratio. Several correlation coefficients between MTRasym and T/N ratio, and APT_T1 and MET T/N ratio were relatively high, but not statistically significant. These preliminary results suggest that parameters on CEST imaging by multi pool model seems to correlate with ¹¹C-MET uptake on PET/CT in patients with gliomas.

Do-Wan Lee¹, Hwon Heo², Chul‐Woong Woo³, Jae-Im Kwon³, Joongkee Min³, Monica Young Choi², Yeon Ji Chae², Dong‐Cheol Woo^2,3, Kyung Won Kim¹, Jeong Kon Kim¹, Hyo Jeong Chin⁴, and Dong‐Hoon Lee^4
1Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of, ²Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of, ³Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, Korea, Republic of, ⁴Department of Radiological Science, College of Health Sciences, Yonsei University, Wonju, Korea, Republic of

Investigations of amide proton signal changes in the white matter of demyelinating diseases may provide important biophysical information for diagnostic and prognostic assessments. We attempted to evaluate in vivo APT_w signal changes within the CC in a reversible cuprizone-induced demyelination rat model using amide proton transfer-weighted (APT_w) MRI at 7-T. We also used immunohistochemical staining to characterize demyelinating and remyelinating activity in the CC following myelin and axon changes. Significant APT_w metric changes coupled with the histological characteristics of the demyelination and remyelination processes indicate the potential usefulness of APT_w 7T MRI to monitor earlier myelination processes.

Jianpan Huang¹, Joseph H. C. Lai¹, Kai-Hei Tse², Gerald W.Y. Cheng², Xiongqi Han¹, Yang Liu¹, Zilin Chen¹, Lin Chen^3,4, Jiadi Xu^3,4, and Kannie W. Y. Chan^1,4,5
1Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China, ²Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China, ³F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States, ⁴Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, ⁵City University of Hong Kong Shenzhen Research Institute, Shenzhen, China

Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is a promising molecular imaging technology. Apparent exchange-dependent relaxation (AREX) provides CEST contrast with less influence of T₁. Here, deep neural network based CEST/AREX analysis methods (CESTNet/AREXNet) were applied to analyze the CEST data of normal and AD mouse brains at 3T. Significant lower amide proton transfer/magnetization transfer (APT/MT) signals related to amyloid β-peptide (Aβ) plaque depositions, which were validated by immunohistochemistry results, were detected in Alzheimer’s disease (AD) mouse brains compared to age-matched wild type (WT) mouse brains. The well-established CESTNet/AREXNet have great potential to facilitate AD identification at 3T.

Zhichao Wang¹, Yu Zhao², Xu Yan³, Zhongshuai Zhang³, Caixia Fu³, Hui Tang⁴, and Jianqi Li^1
1Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai, China, ²Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, ³MR Collaboration NE Asia, Siemens Healthcare, Shanghai, China, ⁴Department of Radiology, Renji Hospital affiliated to Shanghai Jiao Tong University Medical College, Shanghai, China

Chemical exchange saturation transfer (CEST) imaging shows great potential in clinical application. Separating the nuclear Overhauser enhancement (NOE) and amide proton transfer (APT) effects properly is highly valuable for clinical application of CEST. In this study, the background Z-spectra including only the magnetization transfer and direct saturation effects was fitted by using neural network, then CEST and NOE maps were obtained simultaneously. The reproducibility and feasibility of new method were demonstrated in four healthy volunteers and two patients with ischemic stroke.

Rachel W Chan¹, Hatef Mehrabian¹, Hany Soliman², Hanbo Chen², Aimee Theriault², Sten Myrehaug², Chia-Lin Tseng², Jay Detsky², Wilfred W Lam¹, Angus Z Lau^1,3, Gregory J Czarnota^1,2,3, Arjun Sahgal², and Greg J Stanisz^1,3,4
1Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, ²Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, ³Medical Biophysics, Sunnybrook Research Institute, Toronto, ON, Canada, ⁴Department of Neurosurgery and Pediatric Neurosurgery, Medical University, Lublin, Poland

Stereotactic radiosurgery (SRS) is the standard of care treatment for patients with limited brain metastases; however radiation necrosis can develop. Standard clinical approaches have limited ability in differentiating radiation-induced changes from tumor progression. This work examines the performance of CEST metrics (MTR_Amide and MTR_rNOE) at 3T for differentiating radiation necrosis from tumor progression, extending a previous study to include higher saturation power (using B₁=2.0μT) with added multivariable logistic regression. Results in 24 lesions showed that both saturation powers (0.52μT and 2.0μT) could distinguish tumor progression from radiation necrosis, with the MTR_Amide(0.52μT) parameter selected from multivariable modelling with AUC=0.91.

Yu Liu¹, Junchen Li², Ying Wang³, Naying He¹, Zhijia Jin¹, Pei Huang⁴, Shengdi Chen⁴, Fuhua Yan¹, and Ewart Mark Haacke^3
1Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, ²Department of Radiology, Changshu Hospital Affiliated to Nanjing University of Chinese Medicine, Changshu, China, ³Wayne State University, Detroit, MI, United States, ⁴Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China

MSA with a parkinsonian variant (MSA-P) and PD share many common clinical presentations, such as parkinsonism and autonomic failure to mention just a few. The early differential diagnosis of these two disorders has been established more or less empirically despite a lack of a subjective, satisfactory biomarker. Neuroimaging has revolutionized in-vivo visualization of neuromelanin and iron in the substantial nigra (SN), which has been considered as the primary and predominant pathophysiological change in PD patients. We found significant neuromelanin changes in the SN in patients with MSA-P compared with PD and HC.

Kazuhiro Murayama¹, Yoshiharu Ohno², Masao Yui³, Kaori Yamamoto³, Masato Ikedo³, Satomu Hanamatsu², Akiyoshi Iwase⁴, Takashi Fukuba⁴, and Hiroshi Toyama^2
11) Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan, ²Radiology, Fujita Health University School of Medicine, Toyoake, Japan, ³Canon Medical Systems Corporation, Otawara, Japan, ⁴Radiology, Fujita Health University Hospital, Toyoake, Japan

No major reports have been evaluated the capability for the molecular-based assessment by 3D chemical exchange saturation transfer (CEST) imaging and compared with 2D CEST imaging.  We hypothesized that 3D CEST imaging had equal or better potential for the molecular-based assessment in various brain tumor patients, when compared with 2D CEST imaging.  The purpose of this study was to directly compare the capability for molecular-based assessment between 2D and 3D CEST imaging in patients with various brain tumors.

Guixiao Xu¹, Hui Li¹, Yueming Yuan², Liangru Ke¹, Yun He¹, Yanlin Zhu¹, Liyun Zhen², Yingyi Huang¹, Chuanmiao Xie¹, and Yongming Dai^2
1Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in Southern China, Guangzhou, China, ²Central Research Institute, United Imaging Healthcare, Shanghai, China

Nasopharyngeal carcinoma (NPC) prevails in Southeast Asia. Induction chemotherapy (IC) is recommended as the effective treatment for patients with NPC. However, not all patients respond well to IC. Pretreatment identification of the non-responders may help to make treatment more personalized. The amide proton transfer (APT) MRI can give contrast due to exchangeable backbone amide protons of endogenous mobile proteins and peptides, and APT value in tumor has been reported higher. Therefore, the aim of this study is to evaluate whether APT value before treatment correlate to IC response in NPC.