KEYWORDS: Digital signal processing, Signal processing, Optical coherence tomography, Imaging systems, Image restoration, Optical signal processing, Coherence imaging, Image processing, Coherence (optics), Surgery
Optical Coherence Tomography (OCT) imaging is a high-resolution, sub-surface non-invasive imaging technique,
using the principle of low coherence interferometry, that has become increasingly popular for various applications for
structural and quantitative imaging [1]. Applications for OCT technology have been demonstrated in ophthalmology,
dentistry, cardiology/intravascular imaging, endoscopy and intra-operative surgery, and many new applications are being
researched.
Due to higher sensitivity and faster rate of image acquisition, frequency domain OCT systems are now replacing the
first generation time domain systems. These include spectral domain systems, which use a broadband low coherent
source with spectrometer and a line scan camera based receive system, and swept source systems, that use wavelength
sweeping source with a photo-detector based receive system. Both of these systems require very similar signal
processing to recover the desired image from the captured digitized interference or fringe data.
KEYWORDS: Hemodynamics, Functional magnetic resonance imaging, Magnetic resonance imaging, Data modeling, Near infrared spectroscopy, Blood, Sensors, Scanners, Visualization, Brain
Blood oxygenation level dependent (BOLD) response, which is measured by functional magnetic resonance imaging
(fMRI), is known to be a combination of various vascular parameters, among which deoxy-hemoglobin is argued to be a
major contributor. Functional near infrared spectroscopy (fNIRS), though being limited in its spatial resolution, provides
a promising tool to study cortical activations, due to its specificity of independent measurement of blood parameters
(Oxy, De-oxy and Total Hemoglobin), high temporal resolution and ease of use. To study the close relationship between
these imaging modalities, a finger tapping task with stimulus durations (2, 4, 8 & 16 sec) with variable inter-stimulation
intervals was chosen to compare spatio-temporal properties and non-linearity of BOLD signal with HbO, HbR and HBT
signal. This helped determine what parameter (HbO, HbR and HbT) BOLD signals correlate to most and how factors like neural adaptation that cause non-linearity can affect the hemodynamic behavior. It investigates the non-linearity in
HbO, HbR and HbT concentrations as compared to BOLD signal obtained using simultaneous fNIRS and fMRI measurement. Investigating non-linearity in hemodynamic response could provide a better understanding of neuronal function by modeling neural adaptation. The paper also discusses a method to model the neural adaptation and hemodynamic response.
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.