Small separation diffuse correlation spectroscopy for measurement of cerebral blood flow in rodents

Sathialingam, Eashani; Lee, Seung Yup; Sanders, Bharat; Park, Jaekeun; Bryan, Leah; Buckley, Erin M.

doi:10.1364/boe.9.005719

Cited by 17 publications

(21 citation statements)

References 84 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…37 Fits were constrained to g 2 ðr ¼ 1 cm; τÞ > 1.005 and g 2 ðr ¼ 2.5 cm; τÞ > 1.2 to increase sensitivity to the extracerebral and cerebral layers, respectively. 40,41 For all these fits, we assumed an index of refraction of 1.4, and we input the FDNIRS-estimated reduced scattering (μ 0 s ) and absorption (μ a ) coefficients at 852 nm of the corresponding hemisphere in which DCS was measured (see Sec. 6).…”

Section: Dcs Data Analysismentioning

confidence: 99%

Noninvasive optical assessment of resting-state cerebral blood flow in children with sickle cell disease

et al. 2019

Self Cite

View full text Add to dashboard Cite

Sickle cell disease (SCD) is a genetic blood disorder that has profound effects on the brain. Chronic anemia combined with both macro-and microvascular perfusion abnormalities that arise from stenosis or occlusion of blood vessels increased blood viscosity, adherence of red blood cells to the vascular endothelium, and impaired autoregulatory mechanisms in SCD patients all culminate in susceptibility to cerebral infarction. Indeed, the risk of stroke is 250 times higher in children with SCD than in the general population. Unfortunately, while transcranial Doppler ultrasound (TCD) has been widely clinically adopted to longitudinally monitor macrovascular perfusion in these patients, routine clinical screening of microvascular perfusion abnormalities is challenging with current modalities (e.g., positron emission tomography and magnetic resonance imaging) given their high-cost, requirement for sedation in children <6 year, and need for trained personnel. We assess the feasibility of a low-cost, noninvasive optical technique known as diffuse correlation spectroscopy (DCS) to quantify an index of resting-state cortical cerebral blood flow (BFI) in 11 children with SCD along with 11 sex-and age-matched healthy controls. As expected, BFI was significantly higher in SCD subjects compared to healthy controls (p < 0.001). Within SCD subjects, BFI was inversely proportional to resting-state arterial hemoglobin levels (p ¼ 0.012), consistent with expected anemia-induced compensatory vasodilation that aims to maintain adequate oxygen delivery to the tissue. Further, in a subset of patients measured with TCD (n ¼ 7), DCSmeasured blood flow was correlated with TCD-measured blood flow velocity in middle cerebral artery (R s ¼ 0.68), although the trend was not statistically significant (p ¼ 0.11). These results are consistent with those of several previous studies using traditional neuroimaging techniques, suggesting that DCS may be a promising low-cost tool for assessment of tissue-level CBF in pediatric SCD.

show abstract

Section: Dcs Data Analysismentioning

confidence: 99%

Noninvasive optical assessment of resting-state cerebral blood flow in children with sickle cell disease

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…al. showed the validity of diffusion approximation at short source‐detector separations by comparing with Monte Carlo simulations and liquid phantom experiments. For source‐detector separations larger than 3 mm, there was less than 5% error in α D b .…”

Section: Discussionmentioning

confidence: 96%

Longitudinal 3D Blood Flow Distribution Provided by Diffuse Correlation Tomography during Bone Healing in a Murine Fracture Model

Ren

Han

Proctor

et al. 2020

Photochem & Photobiology

View full text Add to dashboard Cite

Noninvasive monitoring of vascularization can potentially diagnose impaired bone healing earlier than current radiographic methods. In this study, a noncontact diffuse correlation tomography (DCT) technique was employed to measure longitudinal blood flow changes during bone healing in a murine femoral fracture model. The three‐dimensional distribution of the relative blood flow was quantified from one day pre‐fracture to 48 days post‐fracture. For three mice, frequent DCT measurements were performed every other day for one week after fracture, and then weekly thereafter. A decrease in blood flow was observed in the bone fracture region at one day post‐fracture, followed by a monotonic increase in blood flow beyond the pre‐injury baseline until five to seven days post‐fracture. For the remaining 12 mice, only weekly DCT measurements were performed. Data collected on a weekly basis show the blood flow for most mice was elevated above baseline during the first two post‐fracture weeks, followed by a subsequent decrease. Torsional strength of the excised femurs was measured for all 15 mice after 7 weeks of healing. A metric based on the early blood flow changes shows a statistically significant difference between the high strength group and the low strength group.

show abstract

“…The first set of simulations consisted of 210 runs modeling different semi-infinite media with each run producing g 1 (τ) for 20 SDS (uniformly spaced between 0.1-2 cm). The optical properties of the media simulated obtained by permuting through five scattering coefficients (µ s : 3 − 15 cm −1 ), seven absorption coefficients (µ a : 0.05 − 0.5 cm −1 ) and six Brownian flow coefficients (D B : 5 × 10 −9 -3 × 10 −8 cm 2 /s) following the ranges as reported recently [31]. These MC simulations were compared against theoretical calculations to assess both the predictions of theory (forward model), as well as parametrization of the simulations (inverse model), as described in Section 2.4.…”

Section: Semi-infinite Modelsmentioning

confidence: 99%

“…However, there could be clinical opportunities for using endoscopically compatible DCS probes to assess tissue perfusion in vivo, which will need to use short SDS for signal acquisition. Further, recent reports have employed DCS measurements at short SDS (<1 cm) for quantifying tissue perfusion in small animal models [27][28][29][30][31]. Surprisingly, these studies all reported that the classical diffusion-theory based theoretical expression in Equation (2) still provided good parametrization of relative changes in tissue perfusion even at short SDS used.…”

Section: Introductionmentioning

confidence: 99%

“…MC simulations can be programmed to incorporate heterogeneous tissue architectures and can be used to accurately model diffuse reflectance and correlation even at short SDS [32,38]. Thus, MC based photon transport methods have been used to compute normalized field correlation in semi-infinite media, simulate intensity correlation decays in complex layered scattering media and to validate improved theoretical models [31,[38][39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Diffuse Correlation Spectroscopy at Short Source-Detector Separations: Simulations, Experiments and Theoretical Modeling

Vishwanath¹,

Zanfardino²

2019

Applied Sciences

View full text Add to dashboard Cite

Diffuse correlation spectroscopy (DCS) has widely been used as a non-invasive optical technique to measure tissue perfusion in vivo. DCS measurements are quantified to yield information about moving scatterers using photon diffusion theory and are therefore obtained at long source-detector separations (SDS). However, short SDS DCS could be used for measuring perfusion in small animal models or endoscopically in clinical studies. Here, we investigate the errors in analytically retrieved flow coefficients from simulated and experimental data acquired at short SDS. Monte Carlo (MC) simulations of photon correlation transport was programmed to simulate DCS measurements and used to (a) examine the accuracy and validity of theoretical analyses, and (b) model experimental measurements made on phantoms at short SDS. Experiments consisted of measurements from a series of optical phantoms containing an embedded flow channel. Both the fluid flow rate and depth of the flow channel from the liquid surface were varied. Inputs to MC simulations required to model experiments were obtained from corrected theoretical analyses. Results show that the widely used theoretical DCS model is robust for quantifying relative changes in flow. We also show that retrieved flow coefficients at short SDS can be scaled to retrieve absolute values via MC simulations.

show abstract

Small separation diffuse correlation spectroscopy for measurement of cerebral blood flow in rodents

Cited by 17 publications

References 84 publications

Noninvasive optical assessment of resting-state cerebral blood flow in children with sickle cell disease

Noninvasive optical assessment of resting-state cerebral blood flow in children with sickle cell disease

Longitudinal 3D Blood Flow Distribution Provided by Diffuse Correlation Tomography during Bone Healing in a Murine Fracture Model

Diffuse Correlation Spectroscopy at Short Source-Detector Separations: Simulations, Experiments and Theoretical Modeling

Contact Info

Product

Resources

About