Laser Speckle Contrast Imaging (LSCI) is a minimally invasive full field optical technique used to generate blood flow maps with high spatial and temporal resolution. The lack of quantitative accuracy the inability predict flows in presence static scatterers such as an intact or thinned skull have been primary limitation LSCI. We present new Multi-Exposure (MESI) instrument that has potential obtain baseline measures. show MESI extends range over which relative measurements are linear. also...

We develop and validate a Modified Beer-Lambert law for blood flow based on diffuse correlation spectroscopy (DCS) measurements.The new formulation enables monitoring from temporal intensity autocorrelation function data taken at single or multiple delay-times.Consequentially, the speed of optical measurement can be substantially increased.The scheme facilitates highly scattering tissues in geometries wherein light propagation is diffusive non-diffusive, it particularly well-suited...

Diffuse correlation spectroscopy (DCS) is an emerging optical modality used to measure cortical cerebral blood flow. This outlook presents a brief overview of the technology, summarizing advantages and limitations method, describing its recent applications animal, adult, infant cohorts. At last, paper highlights future where DCS may play pivotal role individualizing patient management enhancing our understanding neurovascular coupling, activation, brain development.

Monitoring cerebral blood flow (CBF) during neurosurgery can provide important physiological information for a variety of surgical procedures. CBF measurements are assessing whether has returned to presurgical baseline levels and postsurgical tissue viability. Existing techniques intraoperative monitoring based on magnetic resonance imaging expensive often impractical, while such as indocyanine green angiography cannot produce quantitative measures flow. Laser speckle contrast (LSCI) is an...

We introduce, validate and demonstrate a new software correlator for high-speed measurement of blood flow in deep tissues based on diffuse correlation spectroscopy (DCS).The scheme employs standard PC-based data acquisition boards to measure temporal intensity autocorrelation functions continuously at 50 -100 Hz, the fastest measurements reported with DCS date.The streams, obtained vivo typical source-detector separations 2.5 cm, easily resolve pulsatile heart-beat fluctuations which were...

Laser Speckle Contrast Imaging (LSCI) has become a widely used technique to image cerebral blood flow in vivo.However, the quantitative accuracy of changes measured through thin skull not been investigated thoroughly.We recently developed new Multi Exposure (MESI) while accounting for effect scattering from static tissue elements.In this paper we present first vivo demonstration MESI technique.The was mouse cortex following photothrombotic occlusion middle artery.The found accurately...

We present a technique to quantitatively image the phase of thin quasi-transparent samples using extended source incoherent illumination and off-axis detection apertures. Our is achromatic polarization independent, requires no active elements, can be readily adapted standard bright-field microscopes. demonstrate our by reconstructing cheek cells microlens. The light efficient, single-shot nature enables imaging at frame rates that are camera limited.

We introduce and validate a pressure measurement paradigm that reduces extracerebral contamination from superficial tissues in optical monitoring of cerebral blood flow with diffuse correlation spectroscopy (DCS). The scheme determines subject-specific contributions to the DCS signal by utilizing probe modulation induce variations flow. For analysis, head is modeled as two-layer medium probed long short source-detector separations. Then combination modified Beer-Lambert law for enables...

The critical closing pressure ( CrCP) of the cerebral circulation depends on both tissue intracranial and vasomotor tone. CrCP defines arterial blood ABP) at which flow approaches zero, their difference ABP - is an accurate estimate perfusion pressure. Here we demonstrate a novel non-invasive technique for continuous monitoring bedside. methodology combines optical diffuse correlation spectroscopy (DCS) measurements pulsatile in arterioles with concurrent data during cardiac cycle. Together,...

Surgery is the most effective method to cure patients with solid tumors, and 50% of all cancer undergo resection. Local recurrences are due tumor cells remaining in wound, thus we explore near-infrared (NIR) fluorescence spectroscopy imaging identify residual after surgery. Fifteen canines two human spontaneously occurring sarcomas underwent intraoperative imaging. During operation, wounds were interrogated NIR spectroscopy. monitoring identified presence or absence surgery 14/15 a mean...

<h3>Aim</h3> To compare visual outcomes between deep anterior lamellar keratoplasty (DALK) and penetrating (PK). Secondarily to refractive outcomes, complications graft survival the three cohorts. <h3>Methods</h3> Retrospective case-control study evaluating acuity (VA) following DALK with complete Descemet9s baring (DALKa) (modified Anwar big bubble technique—51 eyes), pre-descemetic (DALKm) (manual technique—52 eyes) PK (103 mean follow-up of 13.6, 19.3 18.6 months, respectively....

Cerebral autoregulation (CA) maintains cerebral blood flow (CBF) in the presence of systemic pressure changes. Brain injury can cause loss CA and resulting dysregulation CBF, degree impairment is a functional indicator tissue health. Here, we demonstrate new approach to noninvasively estimate healthy adult volunteers. The employs pulsatile CBF measurements obtained using high-speed diffuse correlation spectroscopy (DCS). Rapid thigh-cuff deflation initiates chain responses that permits...

To describe a quick and simple "small-bubble" technique to immediately determine the success of attaining complete Descemet's membrane (DM) separation from corneal stroma through Anwar's "big-bubble" deep anterior lamellar keratoplasty (DALK) for stromal removal.

We investigate and assess the utility of a simple scheme for continuous absolute blood flow monitoring based on diffuse correlation spectroscopy (DCS). The calibrates DCS using venous-occlusion optical (VO-DOS) measurements arm muscle tissue at single time-point. A calibration coefficient (γ) is determined, permitting conversion indices to units, study healthy adults (N=10) carried out ascertain variability γ. average right (i.e., dominant) was γ=(1.24±0.15)×10(8) (mL·100...

Dynamic cerebral autoregulation (dCA) can be derived from spontaneous oscillations in arterial blood pressure (ABP) and flow (CBF). Transcranial Doppler (TCD) measures CBF-velocity is commonly used to assess dCA. Diffuse correlation spectroscopy (DCS) a promising optical technique for non-invasive CBF monitoring, so here we aimed validate DCS as tool quantifying In 33 healthy adults 17 acute ischemic stroke patients, resting-state hemodynamic were monitored simultaneously with high-speed (20...

Applying copious amounts of fluid to ensure adequate lubrication and cooling during grinding creates environmental safety hazards. The present investigation was undertaken explore the prospects for reducing amount applied without having a deleterious effect on performance. Straight surface experiments were conducted determine flowrate nozzle set-up conditions behaviour both up down grinding. A high-speed camera used observe access zone. For at low flowrates, lack reaching wheel workpiece...

The prevention and treatment of spinal cord injury are focused upon the maintenance blood flow, yet no technology exists to monitor ischemia. We recently demonstrated continuous monitoring ischemia with diffuse correlation optical spectroscopies using an probe. Prior clinical translation this technology, it is critically important demonstrate safety profile exposure required light. To our knowledge, first report in situ testing such a monitor. expose laser light utilizing custom fiber-optic...

Diffuse correlation spectroscopy (DCS), a popular optical technique for fast noninvasive measurement of blood flow, is commonly implemented using expensive fiber-coupled long coherence length laser systems. Here, we report the development portable and fiber-less approach that can be used as low-cost alternative to illuminate tissue in DCS instruments. We validate accuracy noise characteristics source, by comparisons against traditional light sources, with experiments on controlled...

Diffuse Correlation Spectroscopy (DCS) is a widely used non-invasive measurement technique to quantitatively measure deep tissue blood flow. Conventional implementations of DCS use expensive single photon counters as detecting elements and optical probes with bulky fiber optic cables. In recent years, newer approaches flow such Speckle Contrast Analysis (DSCA) Optical (SCOS), have adapted speckle contrast analysis methods simplify measurements using cameras counting avalanche detector arrays...