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Noninvasive Guidance Scheme of Magnetic Nanoparticles for Drug Delivery in Alzheimer’s Disease
Published in Nguyễn T. K. Thanh, Clinical Applications of Magnetic Nanoparticles, 2018
Ali Kafash Hoshiar, Tuan Anh Lea, Faiz Ul Amin, Xingming Zhang, Myeong Ok Kim, Jungwon Yoon
Several methods have been suggested to develop TDD with feedback control, such as by using ultrasound for locating solid microsize particles,82 or using a microscope to track visible particles.83 Magnetic resonance navigation (MRN) is the most effective method for feedback control of TDD. MRN is based primarily on MNPs embedded in microcarriers, which are controlled and tracked using MRI systems.84,85 However, major challenges in a TDD system include generating sufficiently high gradient fields to steer the MNPs and tracking MNPs in real time, to enable precise targeting.86 The dipole field navigation has been suggested to provide at the same time a higher magnetic field strength and magnitude (gradient of 400 mT per meter and 3T field strength at human scale).87
MR neurography of the brachial plexus in adult and pediatric age groups: evolution, recent advances, and future directions
Published in Expert Review of Medical Devices, 2020
Alexander T. Mazal, Ali Faramarzalian, Jonathan D. Samet, Kevin Gill, Jonathan Cheng, Avneesh Chhabra
MRN is a specialized form of MR imaging dedicated to longitudinal visualization and enhanced depiction of peripheral neuromuscular structures. In a normal subject, plexus nerves will appear intermediate to iso-intense in relation to skeletal muscle on non-fat-suppressed T1 and T2-weighted sequences, with intermediate to slightly hyperintense signal on T2 fat-suppressed (T2FS) or short tau inversion recovery (STIR) sequences. The nerves show symmetric appearance bilaterally in terms of signal and caliber, which generally decrease from the scalene triangle to the axilla. The nerves do not enhance on post-contrast sequences unless there is a disruption of the blood nerve barrier, as can be observed in the setting of post-radiation injury, tumor, acute inflammation, or infection [11]. In the setting of such pathologies, affected nerve will also manifest with hyperintense T2 signal changes. With chronic nerve injury or fibrosis, the signal decreases relative to normal nerves.