Jianping Xu¹, Tao Zu¹, Yi-Cheng Hsu², Yi Sun², 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, ²MR Collaboration, Siemens Healthcare Ltd., Shanghai, China

Chemical exchange saturation transfer (CEST) is an emerging molecular imaging technique that can detect various biomolecules in vivo. However, the routine clinical application of CEST MRI is hammered by its long scan time due to the multiple saturation frames acquired. Here, a novel deep neural network modified from the variational network (VN) by utilizing cross-domain regularization structures, dubbed CEST-VN, is proposed for accelerated CEST imaging. In conjunction with multi-coil sensitivity encoding, the CEST-VN method demonstrated superior performance to the conventional parallel imaging and the original VN methods in healthy volunteers and glioma patients.

Wenxuan Chen¹, Lele Ma², Zhensen Chen³, and Xiaolei Song^1
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China, ²State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu, China, ³Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China

We proposed a Rapid Acquisition using Water pre-saturation for quantitative CEST imaging (RAW-qCEST) sequence, which validated by phantom experiments at 3-Tesla. Raw-qCEST allowed rapid acquisition of multiple readouts with varied saturation powers within one TR, by adding a water pre-saturation module that suppress interference among readouts and a seconds-long CEST saturation module before each readout. Simulation and phantom experiments showed that RAW-qCEST could accurately determine pH-related exchange rates, calculated using a modified omega-plot analysis. Owing to its fast speed and quantitative capability, RAW-qCEST could be useful for imaging stroke and cancers, which will be investigated in future.

Yasukage Takami¹, Naruhide Kimura¹, Katsuya Mitamura¹, Takashi Norikane¹, Keisuke Miyake², Tatsuya Yamasaki³, Kazuo Ogawa³, Mitsuharu Miyoshi⁴, Atsushi Nozaki⁴, and Yoshihiro Nishiyama^1
1Department of Radiology, Faculty of Medicine, Kagawa University, Miki-cho, Kita-gun, Japan, ²Department of Neurological Surgery, Faculty of Medicine, Kagawa University, Miki-cho, Kita-gun, Japan, ³Kagawa University Hospital, Miki-cho, Kita-gun, Japan, ⁴GE Healthcare, Hino-shi, Japan

The purpose of this study was to evaluate the correlation among parameters on CEST imaging by multi pool model, IVIM and ¹¹C-methionine (MET) uptake on PET/CT in gliomas. The maximum values of the parameters on CEST imaging, the minimum parameters (ADC, D, D*) and maximum f on IVIM were measured respectively. ¹¹C-MET uptake was semiquantitatively assessed using tumor-to-contralateral normal brain tissue (T/N) ratio. Several strong correlations were observed among some of the parameters. These preliminary results suggest that parameters on CEST imaging by multi pool model and IVIM seems to correlate with ¹¹C-MET uptake on PET/CT in gliomas.

Ying-Hua Chu¹, Patrick Liebig², Yifan Yuan³, He Wang^4,5, and Yi-Cheng Hsu^1
1Siemens Healthineers Ltd., Shanghai, China, ²Siemens Healthcare GmbH, Erlangen, Germany, ³Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China, ⁴Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China, ⁵Human Phenome Institute, Fudan University, Shanghai, China

We proposed a fast 3D CEST imaging method using compressed sensing SPACE and demonstrated its routine clinical application for simultaneous APT, ssMT, and rNOE imaging. The total scan time of CEST images with 58 z-spectra and an off-resonance map was 6 minutes and 49 seconds. We used low refocusing flip angle and high bandwidth to achieve a narrow point spread function, and the images could be reproduced between different scans. This method could be used for tumor grading and treatment response assessment at 3T.

Zhechuan Dai¹, Yi-Cheng Hsu², Yi Sun², 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, Zhejiang, China, ²MR Collaboration, Siemens Healthcare Ltd., Shanghai, China

The inhomogeneity of the main magnetic field (B0) often results in degraded quality of CEST images. Currently, various B0 mapping methods have been used to correct the B0 inhomogeneity of CEST images. Motion inevitably happens between B0 mapping and CEST scans, which, however, is usually ignored in the current CEST processing pipeline. Here, we show that the inclusion of B0 mapping images into the motion correction process improved the quality of the CEST maps, and statistically significantly improved the uniformity indices. Thus, we suggest adding the motion correction of B0 mapping data step into the standard CEST processing pipeline.

Botao Zhao¹ and Xiao-Yong Zhang^1
1Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China

Quantification of chemical exchange saturation transfer (CEST) imaging is a keystone for many clinical applications. Head motion and motion-caused noise produce non-negligible effects on the quantification in the whole brain 3D imaging. To solve the problem, we propose a new motion-based noise reduction method. Our preliminary results demonstrate that our method can reduce the noise efficiently and improve the amide proton transfer (APT) quantification results in the conditions of either with slight head motion or with huge head motion.  

Jianpan Huang¹, Zilin Chen¹, Peter C. M. van Zijl^2,3, Lok Hin Law¹, Rohith Saai Pemmasani Prabakaran^1,4, Se Weon Park¹, Jiadi Xu^2,3, and Kannie W. Y. Chan^1
1Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China, ²F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States, ³Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, ⁴Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China

Dynamic glucose enhanced (DGE) MRI can detect glucose-related events in the brain, however, the influence of oxygen levels on DGE signal remains unknown. Here, we investigated the DGE signal changes under normoxia and hyperoxia on mouse brain, using on-resonance variable delay multi-pulse (onVDMP) MRI. Significantly higher signal change under normoxia than that under hyperoxia was observed in parenchyma but not in cerebrospinal fluid (CSF). Without glucose infusion, a signal increment of about 3% was found in both parenchyma and CSF from hyperoxia to normoxia, interpreted as related to BOLD effect. These data provide insight into the origin of glucoCEST contrast.

Junjiao Hu¹, Huiting Zhang², Hu Guo³, Shan Jiang¹, Weijun Situ¹, Guang Yang⁴, and Jun Liu^1
1Department of Radiology,The Second Xiangya Hospital, Central South University, Changsha, China, ²MR Scientific Marketing, Siemens Healthineers, Wuhan, China, ³MR Application, Siemens Healthineers, Changsha, China, ⁴Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science,East China Normal University, Shanghai, China

The purposed of study was to compare the diagnostic efficacy of APT imaging and four diffusion models, including DTI, DKI, NODDI, and MAP, in evaluating genotype IDH status, and to find the best imaging indicators for aiding accurate diagnoses and treatment decisions. Compared with IDH-mutant gliomas,  IDH-wildtype gliomas had significantly higher mean and maximum of APTw, maximum axial, mean and radial diffusivity from DKI, maximum mean square diffusivity from MAP and maximum isotropic volume fraction  from NODDI, as well as lower minimum APTw value.

Qing Xu¹, Weiqiang Dou², and Jing Ye^1
1Clinical Medical School of Yangzhou University, Northern Jiangsu People’s Hospital, Yangzhou, China, ²GE Healthcare, MR Research, Beijing, China

This study aimed to explore the feasibility of amide proton transfer weighted (APTw) imaging in discriminating fat-poor angiomyolipoma (AML) from clear cell renal cell carcinoma (ccRCC). 19 ccRCC patients and 9 fat-poor AML patients were recruited for APTw imaging. ccRCC group showed significantly higher MTRasym compared to fat-poor AML group (P < 0.05). High AUC of 0.827 in ROC analysis validated the efficacy of APTw imaging in differentiating fat-poor AML from ccRCC. With these findings, APTw imaging may be considered an effective method providing added clinical value in differentiating fat-poor AML from ccRCC.

Hao Song¹, Ali Caglar Özen¹, Stefan Schumann², and Michael Bock^1
1Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, ²Dept. of Anesthesiology and Critical Care, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany

Direct quantification of cerebral metabolic rate of oxygen consumption (CMRO₂) is possible with dynamic ¹⁷O-MRI after inhalation of isotope-enriched ¹⁷O₂. In this work, we investigated oxygen metabolism in posterior fossa tissue including cerebellum, pons and midbrain. The determined CMRO₂ values in these areas were in good agreement with literature values obtained by ¹⁵O-PET studies. Our results demonstrate that dynamic ¹⁷O-MRI may provide a valuable tool for direct measurement of CMRO₂ in posterior fossa tissue.

 

Konstantin Tamarov¹, Gevin von Witte^2,3, Viivi Hyppönen⁴, Jiri Jäntti¹, Aaron Himmler³, Mohammed Albannay², Matthias Ernst³, Sebastian Kozerke², Vesa-Pekka Lehto¹, Joakim Riikonen¹, and Mikko I Kettunen^4
1Department of Applied Physics, University of Eastern Finland, Kuopio, Finland, ²Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland, ³Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland, ⁴A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland

Porous Si nanoparticles (NPs) with different doping degree were prepared using low-load metal assisted catalytic etching and subjected to dynamic nuclear polarization at 3.4 T and 6.7 T. Thermal oxidation of Si was applied to form paramagnetic centers of dangling bond type in Si/SiO₂ interface, which were used to polarize ²⁹Si nuclei. The doping significantly affected the gained polarization and buildup times: high doping degree generally led to lower and faster polarization compared to the low doping. On the other hand, slight p-type or n-type doping was necessary to achieve the highest polarization of about 11 %.

Maria Sedykh¹, Moritz Fabian¹, Kai Herz^2,3, Or Perlman⁴, Christian Farrar⁴, Angelika Mennecke¹, Manuel Schmidt¹, Arnd Dörfler¹, and Moritz Zaiss^1,2
1Neuroradiology, FAU Erlangen-Nuremberg, University Hospital, Erlangen, Germany, ²Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany, ³Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany, ⁴Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States

We report on only one glioblastoma patient, but who could be measured with several different CEST MRI methods: 3T APTw, 3T CEST fingerprinting, and 7T multi-pool CEST in order to reveal their relative performance and correlations. Coarse features can be observed in all methods, with MRF and 7T CEST being more versatile in non-active tumor parts. Isolation, separation and smarter combination of different CEST contrast is still needed to improve the diagnostic performance of CEST.

Chao Zou¹, Yingheng Ruan², Feng Du¹, Qikai Qin³, Qian Wan¹, Jiawen Yuan^1,4, Garth J. Thompson³, Xiaojun Yang², Ye Li¹, Xin Liu¹, and Hairong Zheng^1
1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ²Shenzhen Dingbang Bioscience Co., Ltd., Shenzhen, China, ³iHuman Institute, ShanghaiTech University, Shanghai, China, ⁴Southern University of Science and Technology, Shenzhen, China

Deuterium MRS(I) has emerged as a novel metabolic imaging method. However, the deuterium labeled substrate such as [6,6’-²H₂]glucose is expensive, which becomes one of the obstacles for the clinical translation of this technique. Recently, we developed a cost-effective synthesis route for a new deuterated compound [2,3,4,6,6’-²H₅]glucose. The cost of [2,3,4,6,6’-²H₅]glucose is significantly lower than the [6,6’-²H₂]glucose. In this study, we demonstrate that this new compound can measure the glycolytic flux through a rat glioma model.

Zhensen Chen^1,2, Chuyu Liu³, Yishi Wang⁴, Weibo Chen⁵, Rui Guo⁶, He Wang^1,7, and Xiaolei Song^3
1Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China, ²MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China, ³Department of Biomedical Engineering, School of Medicine Tsinghua University, Beijing, China, ⁴Philips Healthcare, Beijing, China, ⁵Philips Healthcare, Shanghai, China, ⁶Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, ⁷Human Phenome Institute, Fudan University, Shanghai, China

To date, chemical exchange saturation transfer (CEST) is rarely used in abdominal imaging of human body due to its high sensitivity to motion. In this study, we developed a free-breathing abdominal CEST sequence that uses a precise respiratory synchronization strategy and includes a water presaturation module. Preliminary in-vivo experiments showed that the proposed sequence outperformed non-triggered and breath-holding abdominal CEST in reducing the slice position inconsistency between the frequency offsets and motion-induced noise.