APT‐weighted MRI: Techniques, current neuro applications, and challenging issues

• Published in: Journal of magnetic resonance imaging Vol. 50; no. 2; pp. 347 - 364
• Main Authors: Zhou, Jinyuan, Heo, Hye‐Young, Knutsson, Linda, van Zijl, Peter C.M., Jiang, Shanshan
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.08.2019; Wiley Subscription Services, Inc
• Subjects: Alzheimer's disease; Annan fysik; APT‐weighted imaging; Brain; Brain cancer; brain tumor; Brain tumors; CEST imaging; Clinical Medicine; Dependence; Fysik; Head injuries; Image contrast; Klinisk medicin; Magnetic resonance imaging; Medical and Health Sciences; Medical imaging; Medicin och hälsovetenskap; molecular imaging; Movement disorders; Multiple sclerosis; Natural Sciences; Naturvetenskap; Neurodegenerative diseases; Neuroimaging; Organic chemistry; Other Physics Topics; Parkinson's disease; Peptides; pH effects; Physical Sciences; Proteins; Protons; Radiologi och bildbehandling; Radiology and Medical Imaging; Radiology, Nuclear Medicine and Medical Imaging; stroke; Traumatic brain injury; Tumors; CEST imaging; brain tumor; APT-weighted imaging; molecular imaging; stroke
• ISSN: 1053-1807; 1522-2586; 1522-2586
• DOI: 10.1002/jmri.26645

Amide proton transfer‐weighted (APTw) imaging is a molecular MRI technique that generates image contrast based predominantly on the amide protons in mobile cellular proteins and peptides that are endogenous in tissue. This technique, the most studied type of chemical exchange saturation transfer imaging, has been used successfully for imaging of protein content and pH, the latter being possible due to the strong dependence of the amide proton exchange rate on pH. In this article we briefly review the basic principles and recent technical advances of APTw imaging, which is showing promise clinically, especially for characterizing brain tumors and distinguishing recurrent tumor from treatment effects. Early applications of this approach to stroke, Alzheimer's disease, Parkinson's disease, multiple sclerosis, and traumatic brain injury are also illustrated. Finally, we outline the technical challenges for clinical APT‐based imaging and discuss several controversies regarding the origin of APTw imaging signals in vivo. Level of Evidence: 3 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:347–364.