Comparing two methods for assessment of perfusion-diffusion mismatch in a rodent model of ischaemic stroke: a pilot study

Deep Learning of Tissue Fate Features in Acute Ischemic Stroke

In acute ischemic stroke treatment, prediction of tissue survival outcome plays a fundamental role in the clinical decision-making process, as it can be used to assess the balance of risk vs. possible benefit when considering endovascular clot-retrieval intervention. For the first time, we construct a deep learning model of tissue fate based on randomly sampled local patches from the hypoperfusion (Tmax) feature observed in MRI immediately after symptom onset. We evaluate the model with respect to the ground truth established by an expert neurologist four days after intervention. Experiments on 19 acute stroke patients evaluated the accuracy of the model in predicting tissue fate. Results show the superiority of the proposed regional learning framework versus a single-voxel-based regression model.

Magnetic resonance diffusion-perfusion mismatch in acute ischemic stroke: An update

The concept of magnetic resonance perfusion-diffusion mismatch (PDM) provides a practical and approximate measure of the tissue at risk and has been increasingly applied for the evaluation of hyperacute and acute stroke in animals and patients. Recent studies demonstrated that PDM does not optimally define the ischemic penumbra; because early abnormality on diffusion-weighted imaging overestimates the infarct core by including part of the penumbra, and the abnormality on perfusion weighted imaging overestimates the penumbra by including regions of benign oligemia. To overcome these limitations, many efforts have been made to optimize conventional PDM. Various alternatives beyond the PDM concept are under investigation in order to better define the penumbra. The PDM theory has been applied in ischemic stroke for at least three purposes: to be used as a practical selection tool for stroke treatment; to test the hypothesis that patients with PDM pattern will benefit from treatment, while those without mismatch pattern will not; to be a surrogate measure for stroke outcome. The main patterns of PDM and its relation with clinical outcomes were also briefly reviewed. The conclusion was that patients with PDM documented more reperfusion, reduced infarct growth and better clinical outcomes compared to patients without PDM, but it was not yet clear that thrombolytic therapy is beneficial when patients were selected on PDM. Studies based on a larger cohort are currently under investigation to further validate the PDM hypothesis.

Feng Chen's work on translational and clinical imaging

Dr. Feng Chen is a chief medical doctor and the vice chairman of the Department of Radiology in Zhong Da Hospital at Southeast University, Nanjing, China and a senior researcher in the Department of Radiology at the Catholic University of Leuven, Belgium. His main areas of interest are translational imaging research including stroke, tumor angiogenesis, assessment of therapeutic response in solid tumors, and magnetic resonance contrast media. Dr. Feng Chen has published 44 scientific papers in peer-reviewed international journals. He and his colleagues have developed an imaging platform which includes animal models, animal preparations and multiparametric magnetic resonance imaging (MRI) protocols for translational animal imaging research using clinical machines. His MRI findings on rodent stroke are considered to "serve as a model for future laboratory investigations of treatment of acute stroke and unify the approaches developed for clinical studies". He and his colleagues have introduced a novel liver tumor model in rodents, in which a series of studies concerning the antitumor activity of vascular disrupting agents have been successively conducted and assessed by in vivo MRI, especially by diffusion weighted imaging as an imaging biomarker. His goal is to provide valuable references for clinical practice and to contribute to the translation of animal imaging research into patient applications.

[Mechanical recanalization]

Although several studies and registries have focused on new interventional systems for the treatment of acute ischemic stroke, a standard procedure has not yet been established. The procedure itself is still controversially discussed but studies have shown that patients who were successfully treated with mechanical recanalization had a better clinical outcome.