Testing and Calibration of Non-Invasive Optical Imaging Technology for Functional Brain Imaging

Background:

- Non-invasive functional near infrared (fNIR) imaging techniques use infrared light to detect changes in blood volume and oxygen levels during brain activity. fNIR is being studied as a possible way to examine the brain activity of individuals who are unable to undergo standard brain function imaging techniques (such as functional magnetic resonance imaging, or fMRI). For instance, war veterans who have iron shrapnel in the body are not able to have fMRI scans, and very young children or children with autism and related disorders are often not able or willing to cooperate long enough in the MRI environment to allow full imaging studies to take place. Researchers are interested in comparing the results of fNIR and fMRI performed on healthy volunteers to determine if fNIR produces similarly accurate results.

Objectives:

- To examine the capabilities of non-invasive functional near infrared imaging techniques on healthy volunteers and compare the results with the existing outcomes of functional magnetic resonance imaging.

Eligibility:

- Healthy volunteers at least 18 years of age.

Design:

• Participants will have one study visit. Depending on the complexity of the task, the whole exam will take between 5 minutes and 1 hour to perform.
• Participants will be asked to sit as still as possible while wearing a headband that includes light sources and detectors (the fNIR device).
• Participants will be asked to perform a set of tasks (e.g., reading sentences or counting numbers in one's head). Data will be collected during these experiments.

Objective: to cross-validate our near infrared spectroscopy (NIRS) imaging system with existing functional magnetic resonance imaging (fMRI) data, and b) to investigate any significant technical issues associated with optode placement and motion artifacts, and to explore techniques that will potentially improve the feasibility and reliability of the system according to the needs of the population whom existing imaging systems are unsuitable for.

Study population: 40 healthy volunteers

Design: The study will look for correlations between NIRS signal changes in healthy subjects when performing functional tasks, and existing fMRI data.

Outcome Measures: graded changes in blood flow and oxygen, measured with NIRS, in response to different functional tasks.

Note: This study is sponsored by the Center for Neuroscience and Regenerative Medicine (CNRM). De-identified data including imaging data sent to CNRM may be shared with outside investigators or collaborators. This data may be used for a variety of research purposes. The Henry M. Jackson Foundation for the Advancement for Military Medicine (HJF), USUHS, or DoD representatives may also access data for audit purposes.

• Neurovascular Coupling
• Hemoglobin
• Functional Brain Imaging

• Bozkurt A, Onaral B. Safety assessment of near infrared light emitting diodes for diffuse optical measurements. Biomed Eng Online. 2004 Mar 22;3(1):9.
• Friedland RP, Iadecola C. Roy and Sherrington (1890): a centennial reexamination of "On the regulation of the blood-supply of the brain". Neurology. 1991 Jan;41(1):10-4. No abstract available.
• Villringer A, Chance B. Non-invasive optical spectroscopy and imaging of human brain function. Trends Neurosci. 1997 Oct;20(10):435-42. Review.

• INCLUSION CRITERIA:

Age 18 years or greater.

EXCLUSION CRITERIA:

• Healthy volunteers with any skin disease.
• Past or present hematologic abnormality of Hgb less than 9.0 gm/dl.
• Healthy volunteers with any past or present vascular disease
• Known adverse reaction to latex.
• Any medical condition that, in the opinion of the Principal Investigator, would preclude the inclusion of a patient onto this research study.
• Unable or unwilling to give informed consent.

• Center for Neuroscience and Regenerative Medicine (CNRM)
• Department of Defense
• National Institutes of Health Clinical Center (CC)