1. Department of Gastroenterology, Zhongshan Hospital affiliated with Fudan University, 180 Fenglin Road, Shanghai 200032, China
2. Key Laboratory of Smart Drug Delivery, Ministry of Education & PLA, School of Pharmacy, Fudan University, Shanghai 201203, China
3. Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
4. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics & Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China
5. JHU ICMIC Program, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States