Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Medical Biophysics

Supervisor

St. Lawrence, Keith

Abstract

Premature infants are at high risk of neonatal brain injury due to poor cerebrovascular regulation, leading to periods of dangerously low cerebral blood flow (CBF) and possible injury. However, there are currently no established bedside methods of monitoring CBF to alert the intensive care staff to cerebrovascular dysfunction. Diffuse correlation spectroscopy (DCS) is an emerging noninvasive optical technique for monitoring relative CBF. I developed a stand-alone DCS method of monitoring absolute CBF by incorporating a quantitative dynamic contrast-enhanced (DCE) technique. This required modifying a DCS system to capture multi-distance data to measure the tissue optical properties and to perform DCE experiments. The feasibility of the technique was assessed by measuring CBF in piglets under three flow condition. For validation, the tissue optical properties were compared to measurements from time-resolved NIRS. Across 7 animals, a strong linear correlation was observed between CBF values derived using the optical properties at baseline (R2=0.95), hypercapnia (R2=0.83) and hypocapnia (R2=0.88). These results demonstrate that the developed DCS system provides the unique ability to provide real-time monitoring of absolute CBF.

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