High Order Diffusion Imaging Used to Differentiate Cytotoxic and Vasogenic Edema in Humans

Chu-Yu Lee¹, Lina J. Karam¹, Josef P. Debbins²

Diffusion weighted imaging (DWI) has been used to detect ischemic stroke [1,2]. Although its underlying physical mechanism remains unknown, the restricted diffusion at the early stage likely results from cytotoxic edema, and the subsequent escalated diffusion arises from the vasogenic edema [2, 3]. In this work, we studied the feasibility of identifying cytotoxic and vasogenic edema using above two high order diffusion models. This was accomplished by fitting the data of suggestive cases of cytotoxic (n=3) and vasogenic edema (n=2) using stretched exponential and second-order cumulant fits. The measured parameters were compared with those from the control areas to further understand the physical underpinnings of pathological changes of ischemic stroke. Our results showed that \DWI and DKI could be used to detect the cytotoxic and vasogenic edema, and the information they provided beyond conventional DWI may be helpful in identifying the underlying physical mechanisms.