Abstract

Laser speckle contrast imaging has become a widely used tool for dynamic imaging of blood flow, both in animal models and in the clinic. Typically, laser speckle contrast imaging is performed using scientific-grade instrumentation. However, due to recent advances in camera technology, these expensive components may not be necessary to produce accurate images. In this paper, we demonstrate that a consumer-grade webcam can be used to visualize changes in flow, both in a microfluidic flow phantom and in vivo in a mouse model. A two-camera setup was used to simultaneously image with a high performance monochrome CCD camera and the webcam for direct comparison. The webcam was also tested with inexpensive aspheric lenses and a laser pointer for a complete low-cost, compact setup ($90, 5.6 cm length, 25 g). The CCD and webcam showed excellent agreement with the two-camera setup, and the inexpensive setup was used to image dynamic blood flow changes before and after a targeted cerebral occlusion.

© 2013 OSA

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2013 (4)

E. Klijn, H. C. Hulscher, R. K. Balvers, W. P. Holland, J. Bakker, A. J. Vincent, C. M. Dirven, and C. Ince, “Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy,” J. Neurosurg.118(2), 280–286 (2013).
[CrossRef] [PubMed]

Y. Atchia, H. Levy, S. Dufour, and O. Levi, “Rapid multiexposure in vivo brain imaging system using vertical cavity surface emitting lasers as a light source,” Appl. Opt.52(7), C64–C71 (2013).
[CrossRef] [PubMed]

S. M. S. Kazmi, A. B. Parthasarthy, N. E. Song, T. A. Jones, and A. K. Dunn, “Chronic imaging of cortical blood flow using Multi-Exposure Speckle Imaging,” J. Cereb. Blood Flow Metab.33(6), 798–808 (2013).
[CrossRef] [PubMed]

L. Song and D. S. Elson, “Effect of signal intensity and camera quantization on laser speckle contrast analysis,” Biomed. Opt. Express4(1), 89–104 (2013).
[CrossRef] [PubMed]

2012 (1)

2011 (1)

M. M. da Silva, J. R. D. A. Nozela, M. J. Chaves, R. Alves Braga Jr, and H. J. Rabal, “Optical mouse acting as biospeckle sensor,” Opt. Commun.284(7), 1798–1802 (2011).
[CrossRef]

2010 (4)

D. A. Boas and A. K. Dunn, “Laser speckle contrast imaging in biomedical optics,” J. Biomed. Opt.15(1), 011109 (2010).
[CrossRef] [PubMed]

S. Klein, M. Staring, K. Murphy, M. A. Viergever, and J. P. Pluim, “elastix: a toolbox for intensity-based medical image registration,” IEEE Trans. Med. Imaging29(1), 196–205 (2010).
[CrossRef] [PubMed]

A. I. Srienc, Z. L. Kurth-Nelson, and E. A. Newman, “Imaging retinal blood flow with laser speckle flowmetry,” Front. Neuroenergetics2, 128 (2010).
[CrossRef] [PubMed]

A. B. Parthasarathy, E. L. Weber, L. M. Richards, D. J. Fox, and A. K. Dunn, “Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study,” J. Biomed. Opt.15(6), 066030 (2010).
[CrossRef] [PubMed]

2009 (1)

N. Hecht, J. Woitzik, J. P. Dreier, and P. Vajkoczy, “Intraoperative monitoring of cerebral blood flow by laser speckle contrast analysis,” Neurosurg. Focus27(4), E11 (2009).
[CrossRef] [PubMed]

2008 (4)

S. J. Kirkpatrick, D. D. Duncan, and E. M. Wells-Gray, “Detrimental effects of speckle-pixel size matching in laser speckle contrast imaging,” Opt. Lett.33(24), 2886–2888 (2008).
[CrossRef] [PubMed]

A. B. Parthasarathy, W. J. Tom, A. Gopal, X. J. Zhang, and A. K. Dunn, “Robust flow measurement with multi-exposure speckle imaging,” Opt. Express16(3), 1975–1989 (2008).
[CrossRef] [PubMed]

M. Vannoni, M. Trivi, R. Arizaga, H. Rabal, and G. Molesini, “Dynamic speckle imaging with low-cost devices,” Eur. J. Phys.29(5), 967–975 (2008).
[CrossRef]

W. J. Tom, A. Ponticorvo, and A. K. Dunn, “Efficient processing of laser speckle contrast images,” IEEE Trans. Med. Imaging27(12), 1728–1738 (2008).
[CrossRef] [PubMed]

2007 (2)

Z. Wang, S. Hughes, S. Dayasundara, and R. S. Menon, “Theoretical and experimental optimization of laser speckle contrast imaging for high specificity to brain microcirculation,” J. Cereb. Blood Flow Metab.27(2), 258–269 (2007).
[CrossRef] [PubMed]

S. Zhang and T. H. Murphy, “Imaging the impact of cortical microcirculation on synaptic structure and sensory-evoked hemodynamic responses in vivo,” PLoS Biol.5(5), e119 (2007).
[CrossRef] [PubMed]

2006 (1)

B. Kruijt, H. S. Bruijn, A. van der Ploeg-van den Heuvel, H. J. Sterenborg, and D. J. Robinson, “Laser speckle imaging of dynamic changes in flow during photodynamic therapy,” Lasers Med. Sci.21(4), 208–212 (2006).
[CrossRef] [PubMed]

2005 (2)

A. K. Dunn, A. Devor, A. M. Dale, and D. A. Boas, “Spatial extent of oxygen metabolism and hemodynamic changes during functional activation of the rat somatosensory cortex,” Neuroimage27(2), 279–290 (2005).
[CrossRef] [PubMed]

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

2004 (4)

B. Choi, N. M. Kang, and J. S. Nelson, “Laser speckle imaging for monitoring blood flow dynamics in the in vivo rodent dorsal skin fold model,” Microvasc. Res.68(2), 143–146 (2004).
[CrossRef] [PubMed]

C. Ayata, A. K. Dunn, Y. Gursoy-Ozdemir, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Laser speckle flowmetry for the study of cerebrovascular physiology in normal and ischemic mouse cortex,” J. Cereb. Blood Flow Metab.24(7), 744–755 (2004).
[CrossRef] [PubMed]

C. Ayata, H. K. Shin, S. Salomone, Y. Ozdemir-Gursoy, D. A. Boas, A. K. Dunn, and M. A. Moskowitz, “Pronounced hypoperfusion during spreading depression in mouse cortex,” J. Cereb. Blood Flow Metab.24(10), 1172–1182 (2004).
[CrossRef] [PubMed]

T. Durduran, M. G. Burnett, G. Yu, C. Zhou, D. Furuya, A. G. Yodh, J. A. Detre, and J. H. Greenberg, “Spatiotemporal quantification of cerebral blood flow during functional activation in rat somatosensory cortex using laser-speckle flowmetry,” J. Cereb. Blood Flow Metab.24(5), 518–525 (2004).
[CrossRef] [PubMed]

2002 (1)

H. Bolay, U. Reuter, A. K. Dunn, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Intrinsic brain activity triggers trigeminal meningeal afferents in a migraine model,” Nat. Med.8(2), 136–142 (2002).
[CrossRef] [PubMed]

2001 (2)

A. K. Dunn, H. Bolay, M. A. Moskowitz, and D. A. Boas, “Dynamic imaging of cerebral blood flow using laser speckle,” J. Cereb. Blood Flow Metab.21(3), 195–201 (2001).
[CrossRef] [PubMed]

J. D. Briers, “Laser Doppler, speckle and related techniques for blood perfusion mapping and imaging,” Physiol. Meas.22(4), R35–R66 (2001).
[CrossRef] [PubMed]

2000 (1)

J. R. Anderson, D. T. Chiu, R. J. Jackman, O. Cherniavskaya, J. C. McDonald, H. Wu, S. H. Whitesides, and G. M. Whitesides, “Fabrication of Topologically Complex Three-Dimensional Microfluidic Systems in PDMS by Rapid Prototyping,” Anal. Chem.72(14), 3158–3164 (2000).
[CrossRef] [PubMed]

1999 (1)

A. Roggan, M. Friebel, K. Dorschel, A. Hahn, and G. Muller, “Optical Properties of Circulating Human Blood in the Wavelength Range 400-2500 nm,” J. Biomed. Opt.4(1), 36–46 (1999).
[CrossRef] [PubMed]

1996 (1)

J. D. Briers and S. Webster, “Laser speckle contrast analysis (LASCA): a nonscanning, full-field technique for monitoring capillary blood flow,” J. Biomed. Opt.1(2), 174–179 (1996).
[CrossRef] [PubMed]

1991 (1)

E. H. Ratzlaff and A. Grinvald, “A tandem-lens epifluorescence macroscope: hundred-fold brightness advantage for wide-field imaging,” J. Neurosci. Methods36(2-3), 127–137 (1991).
[CrossRef] [PubMed]

1985 (1)

B. D. Watson, W. D. Dietrich, R. Busto, M. S. Wachtel, and M. D. Ginsberg, “Induction of reproducible brain infarction by photochemically initiated thrombosis,” Ann. Neurol.17(5), 497–504 (1985).
[CrossRef] [PubMed]

1982 (1)

J. D. Briers and A. F. Fercher, “Retinal Blood-Flow Visualization by Means of Laser Speckle Photography,” Invest. Ophthalmol. Vis. Sci.22(2), 255–259 (1982).
[PubMed]

1981 (1)

A. F. Fercher and J. D. Briers, “Flow Visualization by Means of Single-Exposure Speckle Photography,” Opt. Commun.37(5), 326–330 (1981).
[CrossRef]

Alves Braga Jr, R.

M. M. da Silva, J. R. D. A. Nozela, M. J. Chaves, R. Alves Braga Jr, and H. J. Rabal, “Optical mouse acting as biospeckle sensor,” Opt. Commun.284(7), 1798–1802 (2011).
[CrossRef]

Anderson, J. R.

J. R. Anderson, D. T. Chiu, R. J. Jackman, O. Cherniavskaya, J. C. McDonald, H. Wu, S. H. Whitesides, and G. M. Whitesides, “Fabrication of Topologically Complex Three-Dimensional Microfluidic Systems in PDMS by Rapid Prototyping,” Anal. Chem.72(14), 3158–3164 (2000).
[CrossRef] [PubMed]

Arizaga, R.

M. Vannoni, M. Trivi, R. Arizaga, H. Rabal, and G. Molesini, “Dynamic speckle imaging with low-cost devices,” Eur. J. Phys.29(5), 967–975 (2008).
[CrossRef]

Atchia, Y.

Ayata, C.

C. Ayata, A. K. Dunn, Y. Gursoy-Ozdemir, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Laser speckle flowmetry for the study of cerebrovascular physiology in normal and ischemic mouse cortex,” J. Cereb. Blood Flow Metab.24(7), 744–755 (2004).
[CrossRef] [PubMed]

C. Ayata, H. K. Shin, S. Salomone, Y. Ozdemir-Gursoy, D. A. Boas, A. K. Dunn, and M. A. Moskowitz, “Pronounced hypoperfusion during spreading depression in mouse cortex,” J. Cereb. Blood Flow Metab.24(10), 1172–1182 (2004).
[CrossRef] [PubMed]

Bakker, J.

E. Klijn, H. C. Hulscher, R. K. Balvers, W. P. Holland, J. Bakker, A. J. Vincent, C. M. Dirven, and C. Ince, “Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy,” J. Neurosurg.118(2), 280–286 (2013).
[CrossRef] [PubMed]

Balvers, R. K.

E. Klijn, H. C. Hulscher, R. K. Balvers, W. P. Holland, J. Bakker, A. J. Vincent, C. M. Dirven, and C. Ince, “Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy,” J. Neurosurg.118(2), 280–286 (2013).
[CrossRef] [PubMed]

Bandyopadhyay, R.

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Boas, D. A.

D. A. Boas and A. K. Dunn, “Laser speckle contrast imaging in biomedical optics,” J. Biomed. Opt.15(1), 011109 (2010).
[CrossRef] [PubMed]

A. K. Dunn, A. Devor, A. M. Dale, and D. A. Boas, “Spatial extent of oxygen metabolism and hemodynamic changes during functional activation of the rat somatosensory cortex,” Neuroimage27(2), 279–290 (2005).
[CrossRef] [PubMed]

C. Ayata, A. K. Dunn, Y. Gursoy-Ozdemir, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Laser speckle flowmetry for the study of cerebrovascular physiology in normal and ischemic mouse cortex,” J. Cereb. Blood Flow Metab.24(7), 744–755 (2004).
[CrossRef] [PubMed]

C. Ayata, H. K. Shin, S. Salomone, Y. Ozdemir-Gursoy, D. A. Boas, A. K. Dunn, and M. A. Moskowitz, “Pronounced hypoperfusion during spreading depression in mouse cortex,” J. Cereb. Blood Flow Metab.24(10), 1172–1182 (2004).
[CrossRef] [PubMed]

H. Bolay, U. Reuter, A. K. Dunn, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Intrinsic brain activity triggers trigeminal meningeal afferents in a migraine model,” Nat. Med.8(2), 136–142 (2002).
[CrossRef] [PubMed]

A. K. Dunn, H. Bolay, M. A. Moskowitz, and D. A. Boas, “Dynamic imaging of cerebral blood flow using laser speckle,” J. Cereb. Blood Flow Metab.21(3), 195–201 (2001).
[CrossRef] [PubMed]

Bolay, H.

H. Bolay, U. Reuter, A. K. Dunn, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Intrinsic brain activity triggers trigeminal meningeal afferents in a migraine model,” Nat. Med.8(2), 136–142 (2002).
[CrossRef] [PubMed]

A. K. Dunn, H. Bolay, M. A. Moskowitz, and D. A. Boas, “Dynamic imaging of cerebral blood flow using laser speckle,” J. Cereb. Blood Flow Metab.21(3), 195–201 (2001).
[CrossRef] [PubMed]

Briers, J. D.

J. D. Briers, “Laser Doppler, speckle and related techniques for blood perfusion mapping and imaging,” Physiol. Meas.22(4), R35–R66 (2001).
[CrossRef] [PubMed]

J. D. Briers and S. Webster, “Laser speckle contrast analysis (LASCA): a nonscanning, full-field technique for monitoring capillary blood flow,” J. Biomed. Opt.1(2), 174–179 (1996).
[CrossRef] [PubMed]

J. D. Briers and A. F. Fercher, “Retinal Blood-Flow Visualization by Means of Laser Speckle Photography,” Invest. Ophthalmol. Vis. Sci.22(2), 255–259 (1982).
[PubMed]

A. F. Fercher and J. D. Briers, “Flow Visualization by Means of Single-Exposure Speckle Photography,” Opt. Commun.37(5), 326–330 (1981).
[CrossRef]

Bruijn, H. S.

B. Kruijt, H. S. Bruijn, A. van der Ploeg-van den Heuvel, H. J. Sterenborg, and D. J. Robinson, “Laser speckle imaging of dynamic changes in flow during photodynamic therapy,” Lasers Med. Sci.21(4), 208–212 (2006).
[CrossRef] [PubMed]

Burnett, M. G.

T. Durduran, M. G. Burnett, G. Yu, C. Zhou, D. Furuya, A. G. Yodh, J. A. Detre, and J. H. Greenberg, “Spatiotemporal quantification of cerebral blood flow during functional activation in rat somatosensory cortex using laser-speckle flowmetry,” J. Cereb. Blood Flow Metab.24(5), 518–525 (2004).
[CrossRef] [PubMed]

Busto, R.

B. D. Watson, W. D. Dietrich, R. Busto, M. S. Wachtel, and M. D. Ginsberg, “Induction of reproducible brain infarction by photochemically initiated thrombosis,” Ann. Neurol.17(5), 497–504 (1985).
[CrossRef] [PubMed]

Chaves, M. J.

M. M. da Silva, J. R. D. A. Nozela, M. J. Chaves, R. Alves Braga Jr, and H. J. Rabal, “Optical mouse acting as biospeckle sensor,” Opt. Commun.284(7), 1798–1802 (2011).
[CrossRef]

Cherniavskaya, O.

J. R. Anderson, D. T. Chiu, R. J. Jackman, O. Cherniavskaya, J. C. McDonald, H. Wu, S. H. Whitesides, and G. M. Whitesides, “Fabrication of Topologically Complex Three-Dimensional Microfluidic Systems in PDMS by Rapid Prototyping,” Anal. Chem.72(14), 3158–3164 (2000).
[CrossRef] [PubMed]

Chiu, D. T.

J. R. Anderson, D. T. Chiu, R. J. Jackman, O. Cherniavskaya, J. C. McDonald, H. Wu, S. H. Whitesides, and G. M. Whitesides, “Fabrication of Topologically Complex Three-Dimensional Microfluidic Systems in PDMS by Rapid Prototyping,” Anal. Chem.72(14), 3158–3164 (2000).
[CrossRef] [PubMed]

Choi, B.

O. Yang and B. Choi, “Laser speckle imaging using a consumer-grade color camera,” Opt. Lett.37(19), 3957–3959 (2012).
[CrossRef] [PubMed]

B. Choi, N. M. Kang, and J. S. Nelson, “Laser speckle imaging for monitoring blood flow dynamics in the in vivo rodent dorsal skin fold model,” Microvasc. Res.68(2), 143–146 (2004).
[CrossRef] [PubMed]

da Silva, M. M.

M. M. da Silva, J. R. D. A. Nozela, M. J. Chaves, R. Alves Braga Jr, and H. J. Rabal, “Optical mouse acting as biospeckle sensor,” Opt. Commun.284(7), 1798–1802 (2011).
[CrossRef]

Dale, A. M.

A. K. Dunn, A. Devor, A. M. Dale, and D. A. Boas, “Spatial extent of oxygen metabolism and hemodynamic changes during functional activation of the rat somatosensory cortex,” Neuroimage27(2), 279–290 (2005).
[CrossRef] [PubMed]

Dayasundara, S.

Z. Wang, S. Hughes, S. Dayasundara, and R. S. Menon, “Theoretical and experimental optimization of laser speckle contrast imaging for high specificity to brain microcirculation,” J. Cereb. Blood Flow Metab.27(2), 258–269 (2007).
[CrossRef] [PubMed]

Detre, J. A.

T. Durduran, M. G. Burnett, G. Yu, C. Zhou, D. Furuya, A. G. Yodh, J. A. Detre, and J. H. Greenberg, “Spatiotemporal quantification of cerebral blood flow during functional activation in rat somatosensory cortex using laser-speckle flowmetry,” J. Cereb. Blood Flow Metab.24(5), 518–525 (2004).
[CrossRef] [PubMed]

Devor, A.

A. K. Dunn, A. Devor, A. M. Dale, and D. A. Boas, “Spatial extent of oxygen metabolism and hemodynamic changes during functional activation of the rat somatosensory cortex,” Neuroimage27(2), 279–290 (2005).
[CrossRef] [PubMed]

Dietrich, W. D.

B. D. Watson, W. D. Dietrich, R. Busto, M. S. Wachtel, and M. D. Ginsberg, “Induction of reproducible brain infarction by photochemically initiated thrombosis,” Ann. Neurol.17(5), 497–504 (1985).
[CrossRef] [PubMed]

Dirven, C. M.

E. Klijn, H. C. Hulscher, R. K. Balvers, W. P. Holland, J. Bakker, A. J. Vincent, C. M. Dirven, and C. Ince, “Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy,” J. Neurosurg.118(2), 280–286 (2013).
[CrossRef] [PubMed]

Dixon, P. K.

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Dorschel, K.

A. Roggan, M. Friebel, K. Dorschel, A. Hahn, and G. Muller, “Optical Properties of Circulating Human Blood in the Wavelength Range 400-2500 nm,” J. Biomed. Opt.4(1), 36–46 (1999).
[CrossRef] [PubMed]

Dreier, J. P.

N. Hecht, J. Woitzik, J. P. Dreier, and P. Vajkoczy, “Intraoperative monitoring of cerebral blood flow by laser speckle contrast analysis,” Neurosurg. Focus27(4), E11 (2009).
[CrossRef] [PubMed]

Dufour, S.

Duncan, D. D.

Dunn, A. K.

S. M. S. Kazmi, A. B. Parthasarthy, N. E. Song, T. A. Jones, and A. K. Dunn, “Chronic imaging of cortical blood flow using Multi-Exposure Speckle Imaging,” J. Cereb. Blood Flow Metab.33(6), 798–808 (2013).
[CrossRef] [PubMed]

D. A. Boas and A. K. Dunn, “Laser speckle contrast imaging in biomedical optics,” J. Biomed. Opt.15(1), 011109 (2010).
[CrossRef] [PubMed]

A. B. Parthasarathy, E. L. Weber, L. M. Richards, D. J. Fox, and A. K. Dunn, “Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study,” J. Biomed. Opt.15(6), 066030 (2010).
[CrossRef] [PubMed]

A. B. Parthasarathy, W. J. Tom, A. Gopal, X. J. Zhang, and A. K. Dunn, “Robust flow measurement with multi-exposure speckle imaging,” Opt. Express16(3), 1975–1989 (2008).
[CrossRef] [PubMed]

W. J. Tom, A. Ponticorvo, and A. K. Dunn, “Efficient processing of laser speckle contrast images,” IEEE Trans. Med. Imaging27(12), 1728–1738 (2008).
[CrossRef] [PubMed]

A. K. Dunn, A. Devor, A. M. Dale, and D. A. Boas, “Spatial extent of oxygen metabolism and hemodynamic changes during functional activation of the rat somatosensory cortex,” Neuroimage27(2), 279–290 (2005).
[CrossRef] [PubMed]

C. Ayata, H. K. Shin, S. Salomone, Y. Ozdemir-Gursoy, D. A. Boas, A. K. Dunn, and M. A. Moskowitz, “Pronounced hypoperfusion during spreading depression in mouse cortex,” J. Cereb. Blood Flow Metab.24(10), 1172–1182 (2004).
[CrossRef] [PubMed]

C. Ayata, A. K. Dunn, Y. Gursoy-Ozdemir, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Laser speckle flowmetry for the study of cerebrovascular physiology in normal and ischemic mouse cortex,” J. Cereb. Blood Flow Metab.24(7), 744–755 (2004).
[CrossRef] [PubMed]

H. Bolay, U. Reuter, A. K. Dunn, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Intrinsic brain activity triggers trigeminal meningeal afferents in a migraine model,” Nat. Med.8(2), 136–142 (2002).
[CrossRef] [PubMed]

A. K. Dunn, H. Bolay, M. A. Moskowitz, and D. A. Boas, “Dynamic imaging of cerebral blood flow using laser speckle,” J. Cereb. Blood Flow Metab.21(3), 195–201 (2001).
[CrossRef] [PubMed]

Durduran, T.

T. Durduran, M. G. Burnett, G. Yu, C. Zhou, D. Furuya, A. G. Yodh, J. A. Detre, and J. H. Greenberg, “Spatiotemporal quantification of cerebral blood flow during functional activation in rat somatosensory cortex using laser-speckle flowmetry,” J. Cereb. Blood Flow Metab.24(5), 518–525 (2004).
[CrossRef] [PubMed]

Durian, D. J.

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Elson, D. S.

Fercher, A. F.

J. D. Briers and A. F. Fercher, “Retinal Blood-Flow Visualization by Means of Laser Speckle Photography,” Invest. Ophthalmol. Vis. Sci.22(2), 255–259 (1982).
[PubMed]

A. F. Fercher and J. D. Briers, “Flow Visualization by Means of Single-Exposure Speckle Photography,” Opt. Commun.37(5), 326–330 (1981).
[CrossRef]

Fox, D. J.

A. B. Parthasarathy, E. L. Weber, L. M. Richards, D. J. Fox, and A. K. Dunn, “Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study,” J. Biomed. Opt.15(6), 066030 (2010).
[CrossRef] [PubMed]

Friebel, M.

A. Roggan, M. Friebel, K. Dorschel, A. Hahn, and G. Muller, “Optical Properties of Circulating Human Blood in the Wavelength Range 400-2500 nm,” J. Biomed. Opt.4(1), 36–46 (1999).
[CrossRef] [PubMed]

Furuya, D.

T. Durduran, M. G. Burnett, G. Yu, C. Zhou, D. Furuya, A. G. Yodh, J. A. Detre, and J. H. Greenberg, “Spatiotemporal quantification of cerebral blood flow during functional activation in rat somatosensory cortex using laser-speckle flowmetry,” J. Cereb. Blood Flow Metab.24(5), 518–525 (2004).
[CrossRef] [PubMed]

Ginsberg, M. D.

B. D. Watson, W. D. Dietrich, R. Busto, M. S. Wachtel, and M. D. Ginsberg, “Induction of reproducible brain infarction by photochemically initiated thrombosis,” Ann. Neurol.17(5), 497–504 (1985).
[CrossRef] [PubMed]

Gittings, A. S.

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Gopal, A.

Greenberg, J. H.

T. Durduran, M. G. Burnett, G. Yu, C. Zhou, D. Furuya, A. G. Yodh, J. A. Detre, and J. H. Greenberg, “Spatiotemporal quantification of cerebral blood flow during functional activation in rat somatosensory cortex using laser-speckle flowmetry,” J. Cereb. Blood Flow Metab.24(5), 518–525 (2004).
[CrossRef] [PubMed]

Grinvald, A.

E. H. Ratzlaff and A. Grinvald, “A tandem-lens epifluorescence macroscope: hundred-fold brightness advantage for wide-field imaging,” J. Neurosci. Methods36(2-3), 127–137 (1991).
[CrossRef] [PubMed]

Gursoy-Ozdemir, Y.

C. Ayata, A. K. Dunn, Y. Gursoy-Ozdemir, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Laser speckle flowmetry for the study of cerebrovascular physiology in normal and ischemic mouse cortex,” J. Cereb. Blood Flow Metab.24(7), 744–755 (2004).
[CrossRef] [PubMed]

Hahn, A.

A. Roggan, M. Friebel, K. Dorschel, A. Hahn, and G. Muller, “Optical Properties of Circulating Human Blood in the Wavelength Range 400-2500 nm,” J. Biomed. Opt.4(1), 36–46 (1999).
[CrossRef] [PubMed]

Hecht, N.

N. Hecht, J. Woitzik, J. P. Dreier, and P. Vajkoczy, “Intraoperative monitoring of cerebral blood flow by laser speckle contrast analysis,” Neurosurg. Focus27(4), E11 (2009).
[CrossRef] [PubMed]

Holland, W. P.

E. Klijn, H. C. Hulscher, R. K. Balvers, W. P. Holland, J. Bakker, A. J. Vincent, C. M. Dirven, and C. Ince, “Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy,” J. Neurosurg.118(2), 280–286 (2013).
[CrossRef] [PubMed]

Huang, Z.

C. Ayata, A. K. Dunn, Y. Gursoy-Ozdemir, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Laser speckle flowmetry for the study of cerebrovascular physiology in normal and ischemic mouse cortex,” J. Cereb. Blood Flow Metab.24(7), 744–755 (2004).
[CrossRef] [PubMed]

H. Bolay, U. Reuter, A. K. Dunn, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Intrinsic brain activity triggers trigeminal meningeal afferents in a migraine model,” Nat. Med.8(2), 136–142 (2002).
[CrossRef] [PubMed]

Hughes, S.

Z. Wang, S. Hughes, S. Dayasundara, and R. S. Menon, “Theoretical and experimental optimization of laser speckle contrast imaging for high specificity to brain microcirculation,” J. Cereb. Blood Flow Metab.27(2), 258–269 (2007).
[CrossRef] [PubMed]

Hulscher, H. C.

E. Klijn, H. C. Hulscher, R. K. Balvers, W. P. Holland, J. Bakker, A. J. Vincent, C. M. Dirven, and C. Ince, “Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy,” J. Neurosurg.118(2), 280–286 (2013).
[CrossRef] [PubMed]

Ince, C.

E. Klijn, H. C. Hulscher, R. K. Balvers, W. P. Holland, J. Bakker, A. J. Vincent, C. M. Dirven, and C. Ince, “Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy,” J. Neurosurg.118(2), 280–286 (2013).
[CrossRef] [PubMed]

Jackman, R. J.

J. R. Anderson, D. T. Chiu, R. J. Jackman, O. Cherniavskaya, J. C. McDonald, H. Wu, S. H. Whitesides, and G. M. Whitesides, “Fabrication of Topologically Complex Three-Dimensional Microfluidic Systems in PDMS by Rapid Prototyping,” Anal. Chem.72(14), 3158–3164 (2000).
[CrossRef] [PubMed]

Jones, T. A.

S. M. S. Kazmi, A. B. Parthasarthy, N. E. Song, T. A. Jones, and A. K. Dunn, “Chronic imaging of cortical blood flow using Multi-Exposure Speckle Imaging,” J. Cereb. Blood Flow Metab.33(6), 798–808 (2013).
[CrossRef] [PubMed]

Kang, N. M.

B. Choi, N. M. Kang, and J. S. Nelson, “Laser speckle imaging for monitoring blood flow dynamics in the in vivo rodent dorsal skin fold model,” Microvasc. Res.68(2), 143–146 (2004).
[CrossRef] [PubMed]

Kazmi, S. M. S.

S. M. S. Kazmi, A. B. Parthasarthy, N. E. Song, T. A. Jones, and A. K. Dunn, “Chronic imaging of cortical blood flow using Multi-Exposure Speckle Imaging,” J. Cereb. Blood Flow Metab.33(6), 798–808 (2013).
[CrossRef] [PubMed]

Kirkpatrick, S. J.

Klein, S.

S. Klein, M. Staring, K. Murphy, M. A. Viergever, and J. P. Pluim, “elastix: a toolbox for intensity-based medical image registration,” IEEE Trans. Med. Imaging29(1), 196–205 (2010).
[CrossRef] [PubMed]

Klijn, E.

E. Klijn, H. C. Hulscher, R. K. Balvers, W. P. Holland, J. Bakker, A. J. Vincent, C. M. Dirven, and C. Ince, “Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy,” J. Neurosurg.118(2), 280–286 (2013).
[CrossRef] [PubMed]

Kruijt, B.

B. Kruijt, H. S. Bruijn, A. van der Ploeg-van den Heuvel, H. J. Sterenborg, and D. J. Robinson, “Laser speckle imaging of dynamic changes in flow during photodynamic therapy,” Lasers Med. Sci.21(4), 208–212 (2006).
[CrossRef] [PubMed]

Kurth-Nelson, Z. L.

A. I. Srienc, Z. L. Kurth-Nelson, and E. A. Newman, “Imaging retinal blood flow with laser speckle flowmetry,” Front. Neuroenergetics2, 128 (2010).
[CrossRef] [PubMed]

Levi, O.

Levy, H.

McDonald, J. C.

J. R. Anderson, D. T. Chiu, R. J. Jackman, O. Cherniavskaya, J. C. McDonald, H. Wu, S. H. Whitesides, and G. M. Whitesides, “Fabrication of Topologically Complex Three-Dimensional Microfluidic Systems in PDMS by Rapid Prototyping,” Anal. Chem.72(14), 3158–3164 (2000).
[CrossRef] [PubMed]

Menon, R. S.

Z. Wang, S. Hughes, S. Dayasundara, and R. S. Menon, “Theoretical and experimental optimization of laser speckle contrast imaging for high specificity to brain microcirculation,” J. Cereb. Blood Flow Metab.27(2), 258–269 (2007).
[CrossRef] [PubMed]

Molesini, G.

M. Vannoni, M. Trivi, R. Arizaga, H. Rabal, and G. Molesini, “Dynamic speckle imaging with low-cost devices,” Eur. J. Phys.29(5), 967–975 (2008).
[CrossRef]

Moskowitz, M. A.

C. Ayata, H. K. Shin, S. Salomone, Y. Ozdemir-Gursoy, D. A. Boas, A. K. Dunn, and M. A. Moskowitz, “Pronounced hypoperfusion during spreading depression in mouse cortex,” J. Cereb. Blood Flow Metab.24(10), 1172–1182 (2004).
[CrossRef] [PubMed]

C. Ayata, A. K. Dunn, Y. Gursoy-Ozdemir, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Laser speckle flowmetry for the study of cerebrovascular physiology in normal and ischemic mouse cortex,” J. Cereb. Blood Flow Metab.24(7), 744–755 (2004).
[CrossRef] [PubMed]

H. Bolay, U. Reuter, A. K. Dunn, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Intrinsic brain activity triggers trigeminal meningeal afferents in a migraine model,” Nat. Med.8(2), 136–142 (2002).
[CrossRef] [PubMed]

A. K. Dunn, H. Bolay, M. A. Moskowitz, and D. A. Boas, “Dynamic imaging of cerebral blood flow using laser speckle,” J. Cereb. Blood Flow Metab.21(3), 195–201 (2001).
[CrossRef] [PubMed]

Muller, G.

A. Roggan, M. Friebel, K. Dorschel, A. Hahn, and G. Muller, “Optical Properties of Circulating Human Blood in the Wavelength Range 400-2500 nm,” J. Biomed. Opt.4(1), 36–46 (1999).
[CrossRef] [PubMed]

Murphy, K.

S. Klein, M. Staring, K. Murphy, M. A. Viergever, and J. P. Pluim, “elastix: a toolbox for intensity-based medical image registration,” IEEE Trans. Med. Imaging29(1), 196–205 (2010).
[CrossRef] [PubMed]

Murphy, T. H.

S. Zhang and T. H. Murphy, “Imaging the impact of cortical microcirculation on synaptic structure and sensory-evoked hemodynamic responses in vivo,” PLoS Biol.5(5), e119 (2007).
[CrossRef] [PubMed]

Nelson, J. S.

B. Choi, N. M. Kang, and J. S. Nelson, “Laser speckle imaging for monitoring blood flow dynamics in the in vivo rodent dorsal skin fold model,” Microvasc. Res.68(2), 143–146 (2004).
[CrossRef] [PubMed]

Newman, E. A.

A. I. Srienc, Z. L. Kurth-Nelson, and E. A. Newman, “Imaging retinal blood flow with laser speckle flowmetry,” Front. Neuroenergetics2, 128 (2010).
[CrossRef] [PubMed]

Nozela, J. R. D. A.

M. M. da Silva, J. R. D. A. Nozela, M. J. Chaves, R. Alves Braga Jr, and H. J. Rabal, “Optical mouse acting as biospeckle sensor,” Opt. Commun.284(7), 1798–1802 (2011).
[CrossRef]

Ozdemir-Gursoy, Y.

C. Ayata, H. K. Shin, S. Salomone, Y. Ozdemir-Gursoy, D. A. Boas, A. K. Dunn, and M. A. Moskowitz, “Pronounced hypoperfusion during spreading depression in mouse cortex,” J. Cereb. Blood Flow Metab.24(10), 1172–1182 (2004).
[CrossRef] [PubMed]

Parthasarathy, A. B.

A. B. Parthasarathy, E. L. Weber, L. M. Richards, D. J. Fox, and A. K. Dunn, “Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study,” J. Biomed. Opt.15(6), 066030 (2010).
[CrossRef] [PubMed]

A. B. Parthasarathy, W. J. Tom, A. Gopal, X. J. Zhang, and A. K. Dunn, “Robust flow measurement with multi-exposure speckle imaging,” Opt. Express16(3), 1975–1989 (2008).
[CrossRef] [PubMed]

Parthasarthy, A. B.

S. M. S. Kazmi, A. B. Parthasarthy, N. E. Song, T. A. Jones, and A. K. Dunn, “Chronic imaging of cortical blood flow using Multi-Exposure Speckle Imaging,” J. Cereb. Blood Flow Metab.33(6), 798–808 (2013).
[CrossRef] [PubMed]

Pluim, J. P.

S. Klein, M. Staring, K. Murphy, M. A. Viergever, and J. P. Pluim, “elastix: a toolbox for intensity-based medical image registration,” IEEE Trans. Med. Imaging29(1), 196–205 (2010).
[CrossRef] [PubMed]

Ponticorvo, A.

W. J. Tom, A. Ponticorvo, and A. K. Dunn, “Efficient processing of laser speckle contrast images,” IEEE Trans. Med. Imaging27(12), 1728–1738 (2008).
[CrossRef] [PubMed]

Rabal, H.

M. Vannoni, M. Trivi, R. Arizaga, H. Rabal, and G. Molesini, “Dynamic speckle imaging with low-cost devices,” Eur. J. Phys.29(5), 967–975 (2008).
[CrossRef]

Rabal, H. J.

M. M. da Silva, J. R. D. A. Nozela, M. J. Chaves, R. Alves Braga Jr, and H. J. Rabal, “Optical mouse acting as biospeckle sensor,” Opt. Commun.284(7), 1798–1802 (2011).
[CrossRef]

Ratzlaff, E. H.

E. H. Ratzlaff and A. Grinvald, “A tandem-lens epifluorescence macroscope: hundred-fold brightness advantage for wide-field imaging,” J. Neurosci. Methods36(2-3), 127–137 (1991).
[CrossRef] [PubMed]

Reuter, U.

H. Bolay, U. Reuter, A. K. Dunn, Z. Huang, D. A. Boas, and M. A. Moskowitz, “Intrinsic brain activity triggers trigeminal meningeal afferents in a migraine model,” Nat. Med.8(2), 136–142 (2002).
[CrossRef] [PubMed]

Richards, L. M.

A. B. Parthasarathy, E. L. Weber, L. M. Richards, D. J. Fox, and A. K. Dunn, “Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study,” J. Biomed. Opt.15(6), 066030 (2010).
[CrossRef] [PubMed]

Robinson, D. J.

B. Kruijt, H. S. Bruijn, A. van der Ploeg-van den Heuvel, H. J. Sterenborg, and D. J. Robinson, “Laser speckle imaging of dynamic changes in flow during photodynamic therapy,” Lasers Med. Sci.21(4), 208–212 (2006).
[CrossRef] [PubMed]

Roggan, A.

A. Roggan, M. Friebel, K. Dorschel, A. Hahn, and G. Muller, “Optical Properties of Circulating Human Blood in the Wavelength Range 400-2500 nm,” J. Biomed. Opt.4(1), 36–46 (1999).
[CrossRef] [PubMed]

Salomone, S.

C. Ayata, H. K. Shin, S. Salomone, Y. Ozdemir-Gursoy, D. A. Boas, A. K. Dunn, and M. A. Moskowitz, “Pronounced hypoperfusion during spreading depression in mouse cortex,” J. Cereb. Blood Flow Metab.24(10), 1172–1182 (2004).
[CrossRef] [PubMed]

Shin, H. K.

C. Ayata, H. K. Shin, S. Salomone, Y. Ozdemir-Gursoy, D. A. Boas, A. K. Dunn, and M. A. Moskowitz, “Pronounced hypoperfusion during spreading depression in mouse cortex,” J. Cereb. Blood Flow Metab.24(10), 1172–1182 (2004).
[CrossRef] [PubMed]

Song, L.

Song, N. E.

S. M. S. Kazmi, A. B. Parthasarthy, N. E. Song, T. A. Jones, and A. K. Dunn, “Chronic imaging of cortical blood flow using Multi-Exposure Speckle Imaging,” J. Cereb. Blood Flow Metab.33(6), 798–808 (2013).
[CrossRef] [PubMed]

Srienc, A. I.

A. I. Srienc, Z. L. Kurth-Nelson, and E. A. Newman, “Imaging retinal blood flow with laser speckle flowmetry,” Front. Neuroenergetics2, 128 (2010).
[CrossRef] [PubMed]

Staring, M.

S. Klein, M. Staring, K. Murphy, M. A. Viergever, and J. P. Pluim, “elastix: a toolbox for intensity-based medical image registration,” IEEE Trans. Med. Imaging29(1), 196–205 (2010).
[CrossRef] [PubMed]

Sterenborg, H. J.

B. Kruijt, H. S. Bruijn, A. van der Ploeg-van den Heuvel, H. J. Sterenborg, and D. J. Robinson, “Laser speckle imaging of dynamic changes in flow during photodynamic therapy,” Lasers Med. Sci.21(4), 208–212 (2006).
[CrossRef] [PubMed]

Suh, S. S.

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Tom, W. J.

A. B. Parthasarathy, W. J. Tom, A. Gopal, X. J. Zhang, and A. K. Dunn, “Robust flow measurement with multi-exposure speckle imaging,” Opt. Express16(3), 1975–1989 (2008).
[CrossRef] [PubMed]

W. J. Tom, A. Ponticorvo, and A. K. Dunn, “Efficient processing of laser speckle contrast images,” IEEE Trans. Med. Imaging27(12), 1728–1738 (2008).
[CrossRef] [PubMed]

Trivi, M.

M. Vannoni, M. Trivi, R. Arizaga, H. Rabal, and G. Molesini, “Dynamic speckle imaging with low-cost devices,” Eur. J. Phys.29(5), 967–975 (2008).
[CrossRef]

Vajkoczy, P.

N. Hecht, J. Woitzik, J. P. Dreier, and P. Vajkoczy, “Intraoperative monitoring of cerebral blood flow by laser speckle contrast analysis,” Neurosurg. Focus27(4), E11 (2009).
[CrossRef] [PubMed]

van der Ploeg-van den Heuvel, A.

B. Kruijt, H. S. Bruijn, A. van der Ploeg-van den Heuvel, H. J. Sterenborg, and D. J. Robinson, “Laser speckle imaging of dynamic changes in flow during photodynamic therapy,” Lasers Med. Sci.21(4), 208–212 (2006).
[CrossRef] [PubMed]

Vannoni, M.

M. Vannoni, M. Trivi, R. Arizaga, H. Rabal, and G. Molesini, “Dynamic speckle imaging with low-cost devices,” Eur. J. Phys.29(5), 967–975 (2008).
[CrossRef]

Viergever, M. A.

S. Klein, M. Staring, K. Murphy, M. A. Viergever, and J. P. Pluim, “elastix: a toolbox for intensity-based medical image registration,” IEEE Trans. Med. Imaging29(1), 196–205 (2010).
[CrossRef] [PubMed]

Vincent, A. J.

E. Klijn, H. C. Hulscher, R. K. Balvers, W. P. Holland, J. Bakker, A. J. Vincent, C. M. Dirven, and C. Ince, “Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy,” J. Neurosurg.118(2), 280–286 (2013).
[CrossRef] [PubMed]

Wachtel, M. S.

B. D. Watson, W. D. Dietrich, R. Busto, M. S. Wachtel, and M. D. Ginsberg, “Induction of reproducible brain infarction by photochemically initiated thrombosis,” Ann. Neurol.17(5), 497–504 (1985).
[CrossRef] [PubMed]

Wang, Z.

Z. Wang, S. Hughes, S. Dayasundara, and R. S. Menon, “Theoretical and experimental optimization of laser speckle contrast imaging for high specificity to brain microcirculation,” J. Cereb. Blood Flow Metab.27(2), 258–269 (2007).
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Zhou, C.

T. Durduran, M. G. Burnett, G. Yu, C. Zhou, D. Furuya, A. G. Yodh, J. A. Detre, and J. H. Greenberg, “Spatiotemporal quantification of cerebral blood flow during functional activation in rat somatosensory cortex using laser-speckle flowmetry,” J. Cereb. Blood Flow Metab.24(5), 518–525 (2004).
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Figures (7)

Fig. 1
Fig. 1

(A) Schematic of the two-camera setup for simultaneous laser speckle imaging with a CCD camera and a webcam using traditional optics and illumination components. A 50-50 beamsplitter separates the light between the two imaging arms. (B) Schematic of the low-cost, compact laser speckle imaging system, where the lenses are inexpensive aspheres and the illumination is a laser pointer. In both (A) and (B), the 532 nm laser is only used for the animal study. (C) and (D) illustrate the two different samples assessed in this study. (C) A microfluidic flow phantom is used for in vitro validation and different flow levels are controlled using a syringe pump. (D) In vivo validation is performed using a mouse prepared with bi-lateral cranial windows for assessment of setup (A) and (B), respectively.

Fig. 2
Fig. 2

Representative speckle contrast images averaged over 10 frames illustrating the location of the ROIs used for analysis (shown in red for color mode and in blue for Bayer mode and CCD images). Speckle contrast images are shown for (A) the webcam acquired in color mode within the two-camera setup (mean K = 0.0536), (B) the webcam acquired in Bayer mode within the two-camera setup (mean K = 0.132), (C) the CCD camera acquired simultaneously with the webcam in Bayer mode (mean K = 0.167), (D) the webcam acquired in color mode in the inexpensive setup (mean K = 0.0676), and (E) the webcam acquired in Bayer mode in the inexpensive setup (mean K = 0.167). The color bar for (D) is the same as that for (A), and the color bar for (E) is the same as that for (B) and (C). Scale bars = 0.5 mm. (F) Cropped profiles are shown for images (A-E). Each profile is averaged over 20 pixels, and is plotted in physical space (mm) with the channel locations lined up for clarity.

Fig. 3
Fig. 3

Scatter plots illustrating the relative flow changes between different speeds of the microfluidic experiment, with a direct comparison between the CCD camera and the webcam in (A), and the webcam in the inexpensive setup vs. the two-camera setup in (B). Speed 2 was used for the baseline flow in (A), and speed 3 was used for the baseline flow in (B). Each point is the average relative flow with error bars in each direction depicting the standard deviations for each camera or setup.

Fig. 4
Fig. 4

Results from the two-camera in vivo experiment, showing registered baseline speckle contrast images for the CCD camera (A) and the webcam (B) with ROI locations used for analysis. Color bars indicate the range of speckle contrast values (K) displayed in the images. Scale bars = 0.5 mm. The plots in (C) and (D) show the time courses for the vessel and parenchyma ROIs, respectively, and show the CCD and webcam (WC) relative flows for each ROI on the same plot for direct comparison. The colors of the ROIs in (A) and (B) match the colors used for the plots in (C) and (D), and the break in the time course was when the green laser was left on continuously for clot formation.

Fig. 5
Fig. 5

Relative blood flow overlay from the two-camera in vivo experiment depicting the reduction in flow after the stroke overlaid over baseline speckle contrast images with a 35% reduction of baseline cutoff for the CCD camera (A) and the webcam (B). Targeted area for photothrombosis is marked with a green circle in each image. Scale bars = 0.5 mm.

Fig. 6
Fig. 6

Results from the inexpensive in vivo experiment, showing baseline speckle contrast images from the webcam with ROI locations used for analysis (A). Color bar indicates the range of speckle contrast values (K) displayed in the image. (B) Relative blood flow overlay depicting the reduction in flow after the stroke overlaid over baseline speckle contrast images with a 35% reduction of baseline cutoff. Targeted area for photothrombosis is marked with a green circle. Scale bars = 0.5 mm. The plots in (C) and (D) show the relative flow time courses for the ROIs split onto two plots for visualization. The colors of the ROIs in (A) match the colors used for the plots in (C) and (D), and the break in the time course was when the green laser was left on continuously for clot formation.

Fig. 7
Fig. 7

The webcam was used for chronic image acquisition from the right cranial window 1-week after the stroke. (A) Color mode white light reflectance image depicting vascular anatomy and (B) speckle contrast image averaged over 10 frames showing blood flow. The drawn-in region depicts the area with reduced blood flow 1-week post stroke. Color bar indicates the range of speckle contrast values (K) displayed in the image. Scale bars = 0.5 mm.

Tables (1)

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Table 1 Linear regression analysis between the measured relative flows from the webcam and CCDa

Equations (2)

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K= σ s I
K(T, τ c )= ( β e 2x 1+2x 2 x 2 ) 1/2 ,

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