SignificanceDiffuse correlation spectroscopy (DCS) is an optical method to measure relative changes in cerebral blood flow (rCBF) in the microvasculature. Each heartbeat generates a pulsatile signal with distinct morphological features that we hypothesized to be related to intracranial compliance (ICC).AimWe aim to study how three features of the pulsatile rCBF waveforms: the augmentation index (AIx), the pulsatility index, and the area under the curve, change with respect to ICC. We describe ICC as a combination of vascular compliance and extravascular compliance.ApproachSince patients with Chiari malformations (CM) (n=30) have been shown to have altered extravascular compliance, we compare the morphology of rCBF waveforms in CM patients with age-matched healthy control (n=30).ResultsAIx measured in the supine position was significantly less in patients with CM compared to healthy controls (p<0.05). Since physiologic aging also leads to changes in vessel stiffness and intravascular compliance, we evaluate how the rCBF waveform changes with respect to age and find that the AIx feature was strongly correlated with age (Rhealthy subjects=−0.63, Rpreoperative CM patient=−0.70, and Rpostoperative CM patients=−0.62, p<0.01).ConclusionsThese results suggest that the AIx measured in the cerebral microvasculature using DCS may be correlated to changes in ICC.
Intracranial pressure (ICP) measurements help monitor patient status following cerebral injury, and currently require implantation of an invasive pressure probe. The potential complications associated with this implantation have restricted the application of ICP measurements in less severe conditions. We propose a non-invasive alternative that derives features from the cardiac waveforms present in near-infrared spectroscopy (NIRS) measurements and inputs these features into a decision tree regressor to estimate ICP. We evaluated this method in nine subjects already fitted with invasive ICP sensors. The non-invasive nature of NIRS instrumentation eases the clinical adoption of this ICP estimation approach.
Current standard-of-care methods for measuring intracranial pressure (ICP) are highly invasive. To overcome this limitation, we recently demonstrated non-invasive quantification of ICP in an animal model using morphological analysis of the pulsatile cerebral blood flow (CBF) measured with Diffuse Correlation Spectroscopy. Here, we present results from a pilot study in pediatric patients admitted to an intensive care unit. We show that the CBF pulsatile waveform changes with ICP. Using a regression forest-based machine learning algorithm on a cohort of patients (n>15) we demonstrate that ICP extraction in humans can be possible, suggesting the potential for successful clinical translation in future.
We have previously developed a non-invasive intracranial pressure sensor based on cerebral blood flow cardiac pulse shape changes. Here, we present steps towards clinical translation in pediatric patients in critical care.
Intracranial pressure (ICP) is an important metric in the management of severe head injury. We show alternatives to today’s standard of highly invasive measurement devices using near-infrared spectroscopy and diffuse correlation spectroscopy to create a real-time ICP monitor. The algorithms were developed and tested in an animal model. First results of a clinical validation will be presented.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.