Noncontact optical imaging of brain hemodynamics in preterm infants: a preliminary study

Abstract

Extremely preterm infants’ hemodynamic instability places them at high risk of brain injury. Currently there is no reliable bedside method to continuously monitor cerebral hemodynamics in the neonatal intensive care unit (NICU). This paper reports a feasibility study to adapt and test an innovative speckle contrast diffuse correlation tomography (scDCT) device for noncontact, high-density, 3D imaging of cerebral blood flow (CBF) in preterm infants. The scDCT scans a focused point near-infrared illumination to multiple source positions for deep tissue penetration, and controls an electron multiplying charge-coupled-device camera with thousands of pixels to achieve a high-density sampling. The optimized scDCT for use in preterm infants was first evaluated against an established diffuse correlation spectroscopy in an infant-head-simulating phantom with known properties. The observed significant correlation between the two measurements verified the capability of scDCT for transcranial brain imaging. The insignificant influence of transparent incubator wall on scDCT measurements was then confirmed by comparing adult forearm blood flow responses to artery cuff occlusions measured inside and outside the incubator. Finally, the scDCT device was moved to the NICU to image CBF variations in two preterm infants. Infant #1 with no major organ deficits showed little CBF fluctuation over the first 3 weeks of life. Infant #2 showed a significant CBF increase after the 2 h pharmacotherapy for patent ductus arteriosus closure. While these CBF variations meet physiological expectations, the fact that no significant changes are noted with peripheral monitoring of blood oxygen saturation suggests necessity of direct cerebral monitoring. This feasibility study with timely technology development is an important and necessary step towards larger clinical studies with more subjects to further validate it for continuous monitoring and instant management of cerebral pathologies and interventions in the NICU.

Speckle contrast diffuse correlation tomography of cerebral blood flow in perinatal disease model of neonatal piglets

“…In addition to this preclinical study, our scDCT has been tested for noninvasive imaging of human preterm brains [38] and human mastectomy skin flaps [36, 78, 79] with a penetration depth of ~10 mm. This depth (10 mm) enables penetrating deeply into human infant brains [38]. We are currently optimizing the system (e.g., wavelengths/powers of laser diodes and sensitivities of cameras) to penetrate deeper with the goal of imaging human adult brains.…”

“…We have preliminarily tested the scDCT for imaging blood flow distributions in tissue/head‐simulating phantoms, rodent brains, and other human tissues including forearm muscles, burn wounds, and mastectomy skin flaps under various medical conditions [31, 35–37]. Very recently, we conducted a preliminary study to test two preterm infant cases in the NICU by scDCT [38]. However, no pathology can be induced in human subjects to comprehensively test the feasibility and accuracy of the device for continuous CBF imaging.…”

Interferometric diffuse optics: recent advances and future outlook

“…In benefitting from 2D cameras, these approaches are akin to SCOS/DSCA (diffuse speckle contrast analysis), which measures BFI from homodyne speckle contrast(s). 11 , 55 – 58 MiDWS and SCOS/DSCA are compared for human brain BFI measurements in Table 2 .…”

“…In benefitting from 2D cameras, these approaches are akin to SCOS/DSCA (diffuse speckle contrast analysis), which measures BFI from homodyne speckle contrast(s). 11,[55][56][57][58] MiDWS and SCOS/DSCA are compared for human brain BFI measurements in Table 2. Is it possible to obtain TOF information while benefitting from the scalability of 2D interferometric approaches?…”

Intraoperative Optical and Fluorescence Imaging of Blood Flow Distributions in Mastectomy Skin Flaps for Identifying Ischemic Tissues

“…We recently developed an innovative, noncontact, camera-based speckle contrast diffuse correlation tomography method for high-density imaging of blood flow distributions in deep tissues (up to approximately 10 mm). [10][11][12][13][14][15][16][17][18][19] Case studies with speckle contrast diffuse correlation tomography were reported for three-dimensional imaging of blood flow distributions in brain, wound/burn tissues, and mastectomy skin flaps. [10][11][12][13][14][15][16][17][18] In this preliminary study, a small group of patients undergoing mastectomies were imaged sequentially by dye-free speckle contrast diffuse correlation tomography and dye-based commercial fluorescence angiography (SPY-PHI; Novadaq/Stryker, Kalamazoo, Mich.) to identify ischemic tissues in mastectomy skin flaps.…”