Assessing blood coagulation status with laser speckle rheology

Tripathi, Markandey M.; Hajjarian, Zeinab; Cott, Elizabeth M. Van; Nadkarni, Seemantini K.

doi:10.1364/boe.5.000817

Cited by 69 publications

(87 citation statements)

References 57 publications

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“…Laser speckle rheology (LSR) is a powerful optical tool for evaluating the viscoelastic properties of materials with many applications in polymer engineering, food sciences, and biomedical imaging [1–7]. The viscoelastic behavior of a material is usually described by the viscoelastic modulus, G * ( ω ), and is often measured by a mechanical rheometer, in which a specimen is sheared between two parallel plates in an oscillatory manner, and the ratio of the exerted stress to the resulting strain is calculated.…”

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confidence: 99%

Estimation of particle size variations for laser speckle rheology of materials

Hajjarian

Nadkarni

2015

Opt. Lett.

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Laser speckle rheology (LSR) is an optical technique for assessing the viscoelastic properties of materials with several industrial, biological, and medical applications. In LSR, the viscoelastic modulus, G* (ω), of a material is quantified by analyzing the temporal fluctuations of speckle patterns. However, the size of scattering particles within the material also influences the rate of speckle fluctuations, independent of sample mechanical properties, and complicates the accurate estimation of G* (ω). Here, we demonstrate that the average particle size may be retrieved from the azimuth-angle dependence of time-averaged speckle intensities, permitting the accurate quantification of the viscoelastic moduli of materials with unknown particle size distribution using LSR.

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confidence: 99%

Estimation of particle size variations for laser speckle rheology of materials

Hajjarian

Nadkarni

2015

Opt. Lett.

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“…These large scattering particles then contribute mainly to the non-fluctuating component of the speckle pattern, which adjusts the g 2 ( t ) plateau level, and represents the elastic behaviour of the clot. The elasticity of the clot, implicated in the plateau level, provides key diagnostic information as it closely correlates with fibrinogen concentration of blood in patients [40]. Thus, due to confinement of larger particles at later stages of coagulation, diffusely moving smaller particles are expected to contribute more to the estimated MSD [17].…”

Section: Discussionmentioning

confidence: 99%

“…Results of our recent studies have demonstrated a close correlation between coagulation metrics measured using laser speckle approaches and clinically-relevant CCT results such as aPTT, PT, and fibrinogen level [40]. In the future, we envision that OTEG may be performed using a test strip with a single drop of blood obtained using a finger-stick method.…”

Section: Discussionmentioning

confidence: 99%

Optical Thromboelastography to evaluate whole blood coagulation

Hajjarian

Tripathi

Nadkarni

2014

Journal of Biophotonics

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Measurement of blood viscoelasticity during clotting provides a direct metric of haemostatic conditions. Therefore, technologies that quantify blood viscoelasticity at the point-of-care are invaluable for diagnosing coagulopathies. We present a new approach, Optical Thromboelastography (OTEG) that measures the viscoelastic properties of coagulating blood by evaluating temporal laser speckle fluctuations, reflected from a few blood drops. During coagulation, platelet-fibrin clot formation restricts the mean square displacements (MSD) of scatterers and decelerates speckle fluctuations. Cross-correlation analysis of speckle frames provides the speckle intensity temporal autocorrelation, g2(t), from which MSD is deduced and the viscoelastic modulus of blood is estimated. Our results demonstrate a close correspondence between blood viscoelasticity evaluated by OTEG and mechanical rheometry. Spatio-temporal speckle analyses yield 2-dimensional maps of clot viscoelasticity, enabling the identification of micro-clot formation at distinct rates in normal and coagulopathic specimens. These findings confirm the unique capability of OTEG for the rapid evaluation of patients’ coagulation status and highlight the potential for point-of-care use. Spatial maps of blood viscoelasticity index, G, during clotting obtained from a normal patient (top row) and a hypo-coagulable patient with low levels of clotting factors (bottom row) at 0, 1, 14, and 30 minutes after kaolin activation. Micro-clots of significant G values appear at early times (~1 min) and continue to progress to form a large blood clot over 30 min in the normal patient. In contrast, in the hypo-coagulable sample, micro-clots of comparable G are only visible at 14 min and the extent and overall clot strength is considerably reduced compared to the normal patient even at 30 min. Scale bars are 100 μm long. These results demonstrate the high sensitivity and spatial resolution of OTEG for detecting incipient micro-clots during very early stages of clot formation in patients.

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“…14,15 On the other hand, microfluidic constriction-based optical detection methods utilize flow rate change of blood in a microfluidic channel by clot formation. 7 The readout is usually performed with simple optical sensors.…”

Section: Introductionmentioning

confidence: 99%

Coagulation measurement from whole blood using vibrating optical fiber in a disposable cartridge

et al. 2017

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, "Coagulation measurement from whole blood using vibrating optical fiber in a disposable cartridge," J. Biomed. Opt. 22(11), 117001 (2017), doi: 10.1117/1.JBO.22.11.117001. Abstract. In clinics, blood coagulation time measurements are performed using mechanical measurements with blood plasma. Such measurements are challenging to do in a lab-on-a-chip (LoC) system using a small volume of whole blood. Existing LoC systems use indirect measurement principles employing optical or electrochemical methods. We developed an LoC system using mechanical measurements with a small volume of whole blood without requiring sample preparation. The measurement is performed in a microfluidic channel where two fibers are placed inline with a small gap in between. The first fiber operates near its mechanical resonance using remote magnetic actuation and immersed in the sample. The second fiber is a pick-up fiber acting as an optical sensor. The microfluidic channel is engineered innovatively such that the blood does not block the gap between the vibrating fiber and the pick-up fiber, resulting in high signal-to-noise ratio optical output. The control plasma test results matched well with the plasma manufacturer's datasheet. Activated-partial-thromboplastin-time tests were successfully performed also with human whole blood samples, and the method is proven to be effective. Simplicity of the cartridge design and cost of readily available materials enable a low-cost point-of-care device for blood coagulation measurements.

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Assessing blood coagulation status with laser speckle rheology

Cited by 69 publications

References 57 publications

Estimation of particle size variations for laser speckle rheology of materials

Estimation of particle size variations for laser speckle rheology of materials

Optical Thromboelastography to evaluate whole blood coagulation

Coagulation measurement from whole blood using vibrating optical fiber in a disposable cartridge

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