title: Suppression of lipid artifacts in amide proton transfer imaging.
abstract: Amide proton transfer (APT) imaging is a type of chemical exchange saturation transfer imaging in which the amide protons of cellular proteins and peptides are saturated and detected via the water resonance. To study this effect, conventional magnetization transfer and direct saturation effects in the frequency-dependent water saturation spectrum (z-spectrum) need to be removed by asymmetry analysis with respect to the water frequency offset. When using echo planar imaging, it was found that unequal pericranial fat saturation at equidistant higher and lower frequencies with respect to water leads to a lipid artifact in APT asymmetry images. It is demonstrated that a chemical-shift-selective refocusing pulse in combination with crusher gradients can suppress this artifact and provide high-quality images.
authors.affiliation: Division of MRI Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2195, USA.
authors.forename: Phillip Zhe
authors.initials: PZ
authors.lastname: Sun
authors.forename: Jinyuan
authors.initials: J
authors.lastname: Zhou
authors.forename: Weiyun
authors.initials: W
authors.lastname: Sun
authors.forename: Judy
authors.initials: J
authors.lastname: Huang
authors.forename: Peter C M
authors.initials: PC
authors.lastname: van Zijl
mesh_terms: D000577:Amides / Q000378:metabolism*; D000818:Animals; D016477:Artifacts; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D007089:Image Enhancement / Q000379:methods*; D050356:Lipid Metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009479:Neuropeptides / Q000378:metabolism*; D011522:Protons; D051381:Rats; D017208:Rats, Wistar; D014867:Water / Q000378:metabolism*
chemical_list: D000577:Amides; D009479:Neuropeptides; D011522:Protons; D014867:Water