Diffuse correlation spectroscopy blood flow monitoring for intraventricular hemorrhage vulnerability in extremely low gestational age newborns

Abstract

In premature infants with an extremely low gestational age (ELGA, < 29 weeks GA), dysregulated changes in cerebral blood flow (CBF) are among the major pathogenic factors leading to germinal matrix/intraventricular hemorrhage (GM/IVH). Continuous monitoring of CBF can guide interventions to minimize the risk of brain injury, but there are no clinically standard techniques or tools for its measurement. We report the feasibility of the continuous monitoring of CBF, including measures of autoregulation, via diffuse correlation spectroscopy (DCS) in ELGA infants using CBF variability and correlation with scalp blood flow (SBF, served as a surrogate measure of systemic perturbations). In nineteen ELGA infants (with 9 cases of GM/IVH) monitored for 6–24 h between days 2–5 of life, we found a strong correlation between CBF and SBF in severe IVH (Grade III or IV) and IVH diagnosed within 72 h of life, while CBF variability alone was not associated with IVH. The proposed method is potentially useful at the bedside for the prompt assessment of cerebral autoregulation and early identification of infants vulnerable to GM/IVH.

Comparing the performance potential of speckle contrast optical spectroscopy and diffuse correlation spectroscopy for cerebral blood flow monitoring using Monte Carlo simulations in realistic head geometries

“…In addition to the different hardware parameters, different conditions of light collection from the tissue were also explored. For the DCS systems, we evaluated the performance differences between single-mode fiber (780 HP, two polarization modes) and few-mode fiber (SMF28, 12 total modes at 850 nm, six total modes at 1064 nm) as several works have utilized few-mode fiber, especially for measurements made at longer source–detector separations 5 , 52 , 53 . To more effectively model the influence of dark counts on the DCS signal, using a previously developed state space model of a single photon detector, 54 realistic series of photon count timestamps were generated considering the fluctuating speckle signal intensity, randomly occurring dark counts and the detector hold off time.…”

“…Diffuse correlation spectroscopy (DCS), an optical technique that relies on sampling the intensity fluctuations of a speckle pattern set-up by diffusely scattered coherent light to quantify deep tissue blood flow, is seeing increased adoption as a non-invasive research tool for cerebral perfusion monitoring in clinical settings including critical care and sleep apnea, and for functional brain imaging 1 – 6 However, as usually implemented, DCS relies on the use of single or few-mode fibers to sample the speckle pattern in conjunction with photon counting detectors to construct the intensity temporal auto-correlation function, g2(τ) 7 . This dramatically limits the photon throughput [e.g., in comparison with near-infrared spectroscopy (NIRS) where large area detectors and multi-mode fiber bundles can be used] and poses practical challenges to the use of DCS in translational studies.…”

Understanding Acquired Brain Injury: A Review

“…Pediatric patients may have acquired ABI from metabolic disturbances (phenylketonuria), systemic illness (sickle cell disease, diabetes), trauma, central nervous system tumors, infections (meningitis or encephalitis), toxins (use of alcohol or anticonvulsants during pregnancy), and clinical treatment such as radiotherapy or chemotherapy for leukemia [ 83 , 84 , 85 , 86 , 87 , 88 , 89 ].…”

Pulsatile microvascular cerebral blood flow waveforms change with intracranial compliance and age

“…These devices are noninvasive and easy to use, making them an attractive option for clinical applications. [1][2][3][4] The use of DCS in clinical settings has been explored for various applications, such as predicting intracranial pressure (ICP), [5][6][7] measuring dynamic cerebral autoregulation in stroke patients, 8 monitoring intraventricular hemorrhage vulnerability in newborns, 9 and estimating critical closing pressure (CrCP). 10,11 Currently, transcranial doppler ultrasound (TCD) is the gold-standard method to measure the cerebral blood flow velocity (CBFV) in the large arteries of the brain.…”