Multi-Exposure Speckle Imaging

Speckle contrast images acquired at different exposures

Multi-exposure speckle imaging (MESI) is an advanced form of laser speckle contrast imaging that offers more robust estimates of flow across a wider range of flow speeds. By revisiting the underlying physics behind LSCI to better account for the presence of static scatterers and capturing imagery at multiple exposure times, MESI enables the chronic tracking of cerebral blood flow. These improvements have allowed us to study the hemodynamics of ischemic stroke across timescales spanning seconds to months after the infarct.

**Chronic imaging of perfusion after ischemic stroke:** MESI used to track cerebral perfusion following an induced photothrombotic stroke. Green denotes areas with moderate flow deficit, while blue denotes areas with severe flow deficit ([Schrandt, 2015](/publication/schrandt-2015/)). — Chronic imaging of perfusion after ischemic stroke: MESI used to track cerebral perfusion following an induced photothrombotic stroke. Green denotes areas with moderate flow deficit, while blue denotes areas with severe flow deficit (Schrandt, 2015).

Imaging the effects of general anesthesia: Isoflurane anesthesia causes significant vasodilation and increases in cerebral blood flow as imaged with MESI (Sullender, 2022).

Publications

Adam Santorelli, Colin Sullender, Christopher Smith, Andrew Dunn. Mesoscale Imaging of Stroke. Awake Behaving Mesoscopic Brain Imaging, 2024.

Qingwei Fang, Alankrit Tomar, Andrew K. Dunn. Wide-field intensity fluctuation imaging. Biomedical Optics Express, 2024.

Michael Williamson, Stephanie Le, Ronald Franzen, Nicole Donlan, Jill Rosow, Mathilda Nicot-Cartsonis, Alexis Cervantes, Benjamin Deneen, Andrew Dunn, Theresa Jones, Michael Drew. Subventricular zone cytogenesis provides trophic support for neural repair in a mouse model of stroke. Nature Communications, 2023.

Qingwei Fang, Chakameh Jafari, Shaun Engelmann, Alankrit Tomar, Andrew Dunn. Interpreting inverse correlation time: From blood flow to vascular network. Optics Communications, 2023.

Colin Sullender, Adam Santorelli, Lisa Richards, Pawan Mannava, Christopher Smith, Andrew Dunn. Using pressure-driven flow systems to evaluate laser speckle contrast imaging. Journal of Biomedical Optics, 2023.

Christopher Smith, Adam Santorelli, Shaun Engelmann, Pawan Mannava, Andrew Dunn. All fiber-based illumination system for multi-exposure speckle imaging. Biomedical Optics Express, 2023.

Adam Santorelli, Colin Sullender, Andrew Dunn. Multi-exposure Speckle Imaging for Quantitative Evaluation of Cortical Blood Flow. Neural Repair, 2023.

Colin Sullender, Lisa Richards, Fei He, Lan Luan, Andrew Dunn. Dynamics of isoflurane-induced vasodilation and blood flow of cerebral vasculature revealed by multi-exposure speckle imaging. Journal of Neuroscience Methods, 2022.

Michael Williamson, Cathleen Joy Fuertes, Andrew Dunn, Michael Drew, Theresa Jones. Reactive astrocytes facilitate vascular repair and remodeling after stroke. Cell Reports, 2021.

Michael Williamson, Ronald Franzen, Cathleen Joy Fuertes, Andrew Dunn, Michael Drew, Theresa Jones. A Window of Vascular Plasticity Coupled to Behavioral Recovery after Stroke. Journal of Neuroscience, 2020.

Fei He, Colin Sullender, Hanlin Zhu, Michael Williamson, Xue Li, Zhengtuo Zhao, Theresa Jones, Chong Xie, Andrew Dunn, Lan Luan. Multimodal mapping of neural activity and cerebral blood flow reveals long-lasting neurovascular dissociations after small-scale strokes. Science Advances, 2020.

Taylor Clark, Colin Sullender, S. M. Shams Kazmi, Brittany Speetles, Michael Williamson, Daniella Palmberg, Andrew Dunn, Theresa Jones. Artery targeted photothrombosis widens the vascular penumbra, instigates peri-infarct neovascularization and models forelimb impairments. Scientific Reports, 2019.

Lisa Richards, S. M. Shams Kazmi, Katherine Olin, James Waldron, Andrew Dunn. Intraoperative multi-exposure speckle imaging of cerebral blood flow. Journal of Cerebral Blood Flow & Metabolism, 2017.

S. M. Shams Kazmi, Rebecca Wu, Andrew Dunn. Evaluating multi-exposure speckle imaging estimates of absolute autocorrelation times. Optics Letters, 2015.

S. M. Shams Kazmi, Ehssan Faraji, Mitchell Davis, Yu-Yen Huang, Xiaojing Zhang, Andrew Dunn. Flux or speed? Examining speckle contrast imaging of vascular flows. Biomedical Optics Express, 2015.

S. M. Shams Kazmi, Lisa Richards, Christian Schrandt, Mitchell Davis, Andrew Dunn. Expanding applications, accuracy, and interpretation of laser speckle contrast imaging of cerebral blood flow. Journal of Cerebral Blood Flow & Metabolism, 2015.

Christian Schrandt, S. M. Shams Kazmi, Theresa Jones, Andrew Dunn. Chronic monitoring of vascular progression after ischemic stroke using multiexposure speckle imaging and two-photon fluorescence microscopy. Journal of Cerebral Blood Flow & Metabolism, 2015.

S. M. Shams Kazmi, Satyajit Balial, Andrew Dunn. Optimization of camera exposure durations for multi-exposure speckle imaging of the microcirculation. Biomedical Optics Express, 2014.

S. M. Shams Kazmi, Lisa Richards, Andrew Dunn. Cerebral Blood Flow Imaging with Laser Speckle Contrast Imaging. Neurovascular Coupling Methods, 2014.

S. M. Shams Kazmi, Ashwin Parthasarathy, Nelly Song, Theresa Jones, Andrew Dunn. Chronic imaging of cortical blood flow using Multi-Exposure Speckle Imaging. Journal of Cerebral Blood Flow & Metabolism, 2013.

Andrew Dunn. Laser Speckle Contrast Imaging of Cerebral Blood Flow. Annals of Biomedical Engineering, 2012.

Ashwin Parthasarathy, S. M. Shams Kazmi, Andrew Dunn. Quantitative imaging of ischemic stroke through thinned skull in mice with Multi Exposure Speckle Imaging. Biomedical Optics Express, 2010.

Ashwin Parthasarathy, W. James Tom, Ashwini Gopal, Xiaojing Zhang, Andrew Dunn. Robust flow measurement with multi-exposure speckle imaging. Optics Express, 2008.