Mike Modo¹, Harmanvir Ghuman², Reem Azar², Ryan Krafty³, Stephen Badylak⁴, and T. Kevin Hitchens^5
1Radiology, University of Pittsburgh, Pittsburgh, PA, United States, ²Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States, ³Biological Science, University of Pittsburgh, Pittsburgh, PA, United States, ⁴Surgery, University of Pittsburgh, Pittsburgh, PA, United States, ⁵Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States

Regenerative medicine is increasingly investigating how an initial pro-inflammatory response convert to a pro-repair response. Implantation of bioscaffolds exploits this mechanism and allows tissue to regrow in large defects. Even the brain, which is known to not regrow tissue spontaneously, can regenerate lost tissue after implantation of a inductive bioscaffold. Little is known about how immune cells respond to the implantation of a bioscaffold. We  here characterized the acute spatiotemporal dynamics of immune cell infiltration into the brain and a bioscaffold by tagging immune cells with perfluorocarbon nanoemulsions for detection by 19F MRI and anatomical context using 1H MRI. 

Frederick C. Damen¹, Changliang Su², Burce Ozgen Mocan¹, Tibor Vályi-Nagy³, Rifeng Jiang⁴, and Kejia Cai^1,5
1Radiology, University of Illinois at Chicago, Chicago, IL, United States, ²Medical Imaging, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong, China, ³Pathology, University of Illinois at Chicago, Chicago, IL, United States, ⁴Radiology, Fujian Medical University Union Hospital, Fuzhou, Fujian, China, ⁵Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, United States

We present our initial findings of applying Multimodal Apparent Diffusion (MAD) MRI, including b-values up to 10,000 s/mm², to analyze subacute stroke lesions for the characterization of stroke lesions based on micro-environment biomarkers in order to guide treatment in clinics. MAD model is able to separate the acquired diffusion weighted signal into flow, and, unimpeded (fluid), hindered, and restricted apparent diffusion components. Significant differences were found in MAD parameters between lesions and normal appearing white matter. Fraction of unimpeded diffusion significantly increased. Hindered diffusion was significantly lower in lesions. On the other hand, restricted diffusion was significantly higher.

Peng Wang¹, Jinjing Wang², Yong Zhang³, Mengmeng Gu⁴, Shiyi Jiang¹, Dawei Yin¹, Wen Sun¹, and Xinfeng Liu^2
1The First Affiliated Hospital of University of Science and Technology of China, Hefei, China, ²Jinling Hospital, Nanjing, China, ³GE Healthcare, Shanghai, China, ⁴Nanjing First Hospital, Nanjing, China

Post-stroke depression (PSD) is a common neuropsychiatric symptom after stroke. The purpose of this study was to investigate the association between lesion locations of brain stroke and PSD occurrence using Voxel-based Lesion-Symptom Mapping (VLSM). VLSM analysis identified clusters within anterior cingulate gyrus, left hippocampus, left lingual lobe where lesions were significantly associated with PSD. The lesion location showed the promise to be used as an independent risk factor of PSD in patients with acute ischemic stroke.

Ankit Kandpal¹, Tanuja Jayas¹, Rupsa Bhattacharjee¹, Rakesh Kumar Gupta², and Anup Singh^1,3,4
1Centre for Biomedical Engineering, Indian Institute of Technology, Delhi, New Delhi, India, ²Department of Radiology, Fortis Memorial Research Institute, Gurugram, India, ³Department of Biomedical Engineering, All India Institute of Medical Sciences, New Delhi, India, ⁴School for Artificial Intelligence, Indian Institute of Technology, Delhi, New Delhi, India

SWI plays a critical role in stroke in demonstration of hemorrhagic transformation of stroke and demonstration of thrombus in the intracranial arteries. Recently it has been used to quantify the penumbra in acute stroke.  It highlights venous vasculature in acute stroke due to hypoxia in the acute ischemic tissue without the need for any contrast injection and adding additional sequence that results in time penalty. The objective of this study was to develop an automatic framework for penumbra detection using only SWI images. Evaluation of segmentation results shows a dice similarity coefficient of 0.72 and a jaccard index of 0.60.