PERFUSION MAPPING WITH MULTIECHO MULTISHOT PARALLEL IMAGING EPI

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Dynamic susceptibility contrast (DSC)-based perfusion-weighted imaging (PWI) can visualize cerebrovascular hemodynamics. Therefore, it may be an important asset to determine tissue-at-risk in acute stroke patients. When used with diffusion-weighted imaging (DWI), it can help to triage patients who would potentially benefit from IV tPA treatment or mechanical thrombectomy. In DSC imaging, an exogenous paramagnetic tracer (e.g., Gd-DTPA or Dy-DTPA) is rapidly injected into the venous system and its passage is tracked through concentration-related T2* changes in the cerebral vascular bed. Echo-planar imaging (EPI) is the standard technique for dynamic susceptibility-contrast (DSC) perfusion MRI. However, EPI suffers from well-known geometric distortions, which can be reduced by increasing the k-space phase velocity. Moreover, the long echo times (TEs) used in DSC lead to signal saturation of the arterial input signal, and hence to severe quantitation errors in the hemodynamic information.