title: Correcting the detrimental effects of nonuniform intensity distribution on fiber-transmitting laser speckle imaging of blood flow.
abstract: Laser speckle spatial contrast analysis (LSSCA) is superior to laser speckle temporal contrast analysis (LSTCA) in monitoring the fast change in blood flow due to its advantage of high temporal resolution. However, the application of LSSCA which is based on spatial statistics may be limited when there is nonuniform intensity distribution such as fiber-transmitting laser speckle imaging. In this study, we present a normalized laser speckle spatial contrast analysis (nLSSCA) to correct the detrimental effects of nonuniform intensity distribution on the spatial statistics. Through numerical simulation and phantom experiments, it is found that just ten frames of dynamic laser speckle images are sufficient for nLSSCA to achieve effective correction. Furthermore, nLSSCA has higher temporal resolution than LSTCA to respond the change in velocity. LSSCA, LSTCA and nLSSCA are all applied in the fiber-transmitting laser speckle imaging system to analyze the change of cortical blood flow (CBF) during cortical spreading depression (CSD) in rat cortex respectively, and the results suggest that nLSSCA can examine the change of CBF more accurately. For these advantages, nLSSCA could be a potential tool for fiber-transmitting/endoscopic laser speckle imaging.
authors.affiliation: Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Zhang
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Li
authors.forename: Nengyun
authors.initials: N
authors.lastname: Feng
authors.forename: Jianjun
authors.initials: J
authors.lastname: Qiu
authors.forename: Bing
authors.initials: B
authors.lastname: Li
authors.forename: Weihua
authors.initials: W
authors.lastname: Luo
authors.forename: Qingming
authors.initials: Q
authors.lastname: Luo
mesh_terms: D001158:Arteries / Q000502:physiology*; D016477:Artifacts; D001783:Blood Flow Velocity / Q000502:physiology*; D005336:Fiber Optic Technology / Q000295:instrumentation*; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D017078:Laser-Doppler Flowmetry / Q000295:instrumentation*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity