Phillip Zhe Sun1, Jerry S. Cheung1, Enfeng Wang1, Eng H. Lo2
1Radiology, Athinoula. A. Martinos Center for Biomedical Imaging, MGH & Harvard Medical School, Charlestown, MA, United States; 2Radiology & Neurology, Neuroprotection Research Laboratory, MGH & Harvard Medical School, Charlestown, MA, United States
Amide proton transfer (APT), a variation of chemical exchange saturation transfer (CEST) MRI, is sensitive to pH, and has been increasingly used to image stroke. Here, we characterized acute ischemic stroke with localized proton MRS and multi-parametric imaging of pH-weighted APT, perfusion, diffusion and relaxation MRI. We showed that both diffusion and pH-weighted APT MRI strongly correlate with tissue lactate content, while no significant relationship was found for perfusion, T1 and T2 MRI. In summary, our study demonstrated that pH-weighted endogenous APT/CEST MRI, by sensitizing to tissue acidosis, serves as a surrogate metabolic imaging marker for characterizing ischemic tissue damage.