scholarly journals A mechanical mounting system for functional near-infrared spectroscopy brain imaging studies

2005 ◽  
Author(s):  
Shirley Coyle ◽  
Charles Markham ◽  
William Lanigan ◽  
Tomas Ward
Keyword(s):  
Infrared Spectroscopy ◽  
Brain Imaging ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Imaging Studies ◽  
Functional Near Infrared Spectroscopy

scholarly journals The Temporal Confounding Effects of Extra-cerebral Contamination Factors on the Hemodynamic Signal Measured by Functional Near-Infrared Spectroscopy

2019 ◽  
Vol 10 (5) ◽  
pp. S73-S81
Author(s):  
Mehrdad Zarei ◽  
Mohammad Ali Ansari ◽  
Kourosh Zare
Keyword(s):  
Blood Flow ◽  
Monte Carlo ◽  
Infrared Spectroscopy ◽  
Brain Imaging ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Temporal Changes ◽  
Hemodynamic Changes ◽  
Functional Near Infrared Spectroscopy ◽  
Large Source

Introduction: Functional near-infrared spectroscopy (fNIRS) has been broadly applied for optical brain imaging. This method is hemodynamic-based functional brain imaging relying on the measurement of the neurovascular coupling to detect changes in cerebral neuronal activities. The extra-cerebral hemodynamic changes are important contaminating factors in fNIRS measurements. This error signal can be misinterpreted as cerebral activities during fNIRS studies. Recently, it was assumed that temporal changes in deoxygenated hemoglobin concentration [HHb] was hardly affected by superficial blood flow, and it was proposed that the activation maps could be determined from [HHb] at large source-detector separation. Methods: In the current study, we measured the temporal changes in [HHb] using a continueswave fNIRS device at large source-detector separation, while superficial blood flow was stimulated by infrared lasers. A mesh-based Monte Carlo code was applied to estimate fNIRS sensitivity to superficial hemodynamic changes in a realistic 3D MRI-based brain phantom. Results: First, we simulated photon migration in a four-layered human-head slab model to calculate PPLs and fNIRS sensitivity. Then, the localization of the infrared laser inside a realistic brain model was studied using the Monte Carlo method. Finally, the changes in [HHb] over the prefrontal cortex of six adult males were measured by fNIRS at a source-detector separation of 3 cm. The results demonstrated that the relation between fNIRS sensitivity and an increase in S-D separation was nonlinear and a correlation between shallow and deep signals was observed. Conclusion: The presented results demonstrated that the temporal changes in the superficial blood flow could strongly affect HHb measurement at large source-detector separation. Hence, the cerebral activity map extracted from the [HHb] signal was mainly contaminated by superficial blood flow.

THE EVOLUTION OF FIELD DEPLOYABLE fNIR SPECTROSCOPY FROM BENCH TO CLINICAL SETTINGS

2011 ◽  
Vol 04 (03) ◽  
pp. 239-250 ◽  
Author(s):  
KURTULUS IZZETOGLU ◽  
HASAN AYAZ ◽  
ANNA MERZAGORA ◽  
MELTEM IZZETOGLU ◽  
PATRICIA A. SHEWOKIS ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Brain Imaging ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Continuous Wave ◽  
Home Monitoring ◽  
Quantitative Information ◽  
Functional Near Infrared Spectroscopy ◽  
Operational Conditions ◽  
Britton Chance

In the late 1980s and early 1990s, Dr. Britton Chance and his colleagues, using picosecond-long laser pulses, spearheaded the development of time-resolved spectroscopy techniques in an effort to obtain quantitative information about the optical characteristics of the tissue. These efforts by Chance and colleagues expedited the translation of near-infrared spectroscopy (NIRS)-based techniques into a neuroimaging modality for various cognitive studies. Beginning in the early 2000s, Dr. Britton Chance guided and steered the collaboration with the Optical Brain Imaging team at Drexel University toward the development and application of a field deployable continuous wave functional near-infrared spectroscopy (fNIR) system as a means to monitor cognitive functions, particularly during attention and working memory tasks as well as for complex tasks such as war games and air traffic control scenarios performed by healthy volunteers under operational conditions. Further, these collaborative efforts led to various clinical applications, including traumatic brain injury, depth of anesthesia monitoring, pediatric pain assessment, and brain–computer interface in neurology. In this paper, we introduce how these collaborative studies have made fNIR an excellent candidate for specified clinical and research applications, including repeated cortical neuroimaging, bedside or home monitoring, the elicitation of a positive effect, and protocols requiring ecological validity. This paper represents a token of our gratitude to Dr. Britton Chance for his influence and leadership. Through this manuscript we show our appreciation by contributing to his commemoration and through our work we will strive to advance the field of optical brain imaging and promote his legacy.

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