Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine
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Studies have linked low pH and loss of glycosaminoglycan (GAG) in the intervertebral discs (IVDs) of patients with discogenic back pain. The purpose of this study is to determine whether the chemical exchange saturation transfer (CEST) effect of GAG (gagCEST) is pH dependent and whether it can be used to detect pH changes in IVD specimens. Iopromide, a Food and Drug Administration approved agent for CT/X-Ray, was also evaluated as a pH-sensitive CEST probe to explore the agents' potential to measure IVD pH. ⋯ gagCEST is sensitive to pH and enables investigation of the IVD pH status. Iopromide CEST is independent of the local GAG concentration and has the potential for measuring pH in the IVD.
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There is a clinical need for noninvasive, nonionizing imaging biomarkers of tumor hypoxia and oxygenation. We evaluated the relationship of T1 -weighted oxygen-enhanced magnetic resonance imaging (OE-MRI) measurements to histopathology measurements of tumor hypoxia in a murine glioma xenograft and demonstrated technique translation in human glioblastoma multiforme. ⋯ These data support further investigation of T1 -weighted OE-MRI to identify regional tumor hypoxia. The quantification of AUCOE has translational potential as a clinical biomarker of hypoxia.
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The quantification of myocardial perfusion using a Look-Locker flow-sensitive alternating inversion recovery- arterial spin labeling experiment is considered. Due to the anatomy of the heart, a substantial but unintended partial inversion of the inflowing blood occurs during the slice-selective inversion. Both, the partial inversion as well as the Look-Locker pulse train, influence the myocardial perfusion quantification and are addressed in this work. ⋯ It is shown that the Look-Locker readout as well as the nonideal slice-selective inversion experiment have a considerable influence and have to be included properly to correctly quantify myocardial perfusion.
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A technique is described for simultaneous multislice (SMS) excitation using radiofrequency (RF) parallel transmission (pTX). ⋯ The proposed SMS-pTX allows SMS excitations at reduced RF power by exploiting the local B(1)(+) sensitivities of suitable multielement pTX arrays.
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To demonstrate the capability of incorporating independent shims into a dual-band spectral-spatial excitation and to compare fat suppression between standard global shims and independent shims for in vivo bilateral breast imaging at 1.5T. ⋯ Incorporating independent shims into the dual-band spectral-spatial excitation can provide homogeneous fat suppression in bilateral breast imaging.