Near infrared spectroscopy in large animals: optical pathlength and influence of hair covering and epidermal pigmentation.
Abstract: The effects of epidermal pigmentation and hair covering on the relative transparency of various animal tissues to near infrared (NIR) light were examined, and the pathlengths of NIR light through tissues at four wavelengths in the NIR range were subsequently determined. Black hair covering and black or dark-coloured hooves prevented NIR light from penetration sufficient for conduction of pathlength or NIR spectroscopy measurements. Non-pigmented hair covering of the head did not appear to be a barrier to successful NIR light transmission. Tissues sufficiently transparent to NIR light had the differential pathlength factor (DPF, i.e. the ratio of the observed light pathlength and the geometric light source-detector separation) of NIR light determined by intensity modulated spectroscopy at the wavelengths 744, 806, 834 and 860 nm. Horse gluteal muscles had DPFs of 6.2, 6.2, 6.0, and 5.6, whereas forelimb muscles had DPF of 4.7, 4.4, 4.5 and 3.9 at the respective wavelengths. Sheep heads had DPF of 7.2 +/- 0.3, 5.8 +/- 0.5, 5.5 +/- 0.4 and 4.4 +/- 0.6 (+/- SEM) for the above respective wavelengths, of which the pathlengths all differed significantly from the other, except for between 806 and 834 nm, and 834 and 860 nm. The DPF of horse hooves were 4.8 +/- 0.1, 4.8 +/- 0.1, 4.7 +/- 0.1 and 4.4 +/- 0.1 (SEM) for the above noted wavelengths, of which the pathlength at 744 and 806 nm differed from the pathlength at 860 nm (P>0.05). These results show that NIRS is possible through lighter pigmented hair and epidermal tissues, and provide DPFs of horse feet and muscle and the sheep head that enables quantitative NIRS in these species
Copyright 1999 Baillière Tindall.
Publication Date: 1999-07-20 PubMed ID: 10409416DOI: 10.1053/tvjl.1998.0306Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research investigates how the transparency of animal tissues to near-infrared (NIR) light is influenced by hair covering and skin color. The study found that darker hair and hooves block NIR light, preventing adequate measurement, while non-pigmented hair does not pose an issue. Tissue transparency to NIR light and associated path length details from the research provide key numbers for quantitative NIR spectroscopy application in horses and sheep.
Effects on NIR Light Transmission
- Researchers studied how near-infrared light (NIR) penetrates various types of animal tissues. The two main factors considered were epidermal pigmentation (skin color) and hair covering. These factors were examined for their potential to inhibit the transmission of NIR light.
- The study found that dark-colored hair covering (specifically, black hair) and dark-colored hooves significantly block the penetration of NIR light. This presented a challenge in conducting pathlength or NIR spectroscopy measurements.
- On the other hand, animal tissues covered with non-pigmented (light-colored or white) hair showed no signs of inhibiting NIR light transmission.
Measurement of Differential Pathlength Factor
- The relative transparency of animal tissues to NIR light was evaluated using the differential pathlength factor (DPF), which describes the ratio of the observed light pathlength to the geometric light source-detector separation.
- This was done at four different NIR wavelengths: 744, 806, 834, and 860 nm.
- The DPF measurements revealed significant differences between various types of tissues and different animal species. For instance, horse gluteal muscles exhibited DPF values between 5.6 and 6.2, whereas their forelimb muscles showed lower DPF values, between 3.9 and 4.7. Sheep head tissues had an even broader range of DPF values.
Implications of the Study
- The study’s findings indicate that NIR spectroscopy measurements are feasible on tissues covered with light-pigmented hair and certain epidermal tissues. This is critical in selecting suitable animal species and their body parts for NIR spectroscopy experiments.
- The DPF values obtained for horse feet and muscles, and sheep heads, provide essential insights for implementing quantitative NIR spectroscopy in these species.
- While the research proved that hair color and skin pigmentation play a significant role in NIR light penetration, to expand on these results, future studies may consider additional factors, such as the thickness of the animal’s skin and other biological or environmental variables.
Cite This Article
APA
Pringle J, Roberts C, Kohl M, Lekeux P.
(1999).
Near infrared spectroscopy in large animals: optical pathlength and influence of hair covering and epidermal pigmentation.
Vet J, 158(1), 48-52.
https://doi.org/10.1053/tvjl.1998.0306 Publication
Researcher Affiliations
- Service of Physiology, Faculty of Veterinary Medicine, Bât 42, Bât 42, B-4000, Belgium. john.pringle@kirmed.slu.se
MeSH Terms
- Animals
- Cattle / physiology
- Hair / physiology
- Head / physiology
- Hoof and Claw / physiology
- Horses / physiology
- Muscle, Skeletal / physiology
- Sheep / physiology
- Skin Pigmentation / physiology
- Spectroscopy, Near-Infrared / veterinary
Citations
This article has been cited 10 times.- Kwasa J, Peterson HM, Karrobi K, Jones L, Parker T, Nickerson N, Wood S. Demographic reporting and phenotypic exclusion in fNIRS.. Front Neurosci 2023;17:1086208.
- Vidal-Rosas EE, von Lühmann A, Pinti P, Cooper RJ. Wearable, high-density fNIRS and diffuse optical tomography technologies: a perspective.. Neurophotonics 2023 Apr;10(2):023513.
- Shatzer HE, Russo FA. Brightening the Study of Listening Effort with Functional Near-Infrared Spectroscopy: A Scoping Review.. Semin Hear 2023 May;44(2):188-210.
- Tolleson DR, Schafer DW. Evaluation of non-invasive bioforensic techniques for determining the age of hot-iron brand burn scars in cattle.. Transl Anim Sci 2021 Jul;5(3):txab108.
- Chincarini M, Dalla Costa E, Qiu L, Spinelli L, Cannas S, Palestrini C, Canali E, Minero M, Cozzi B, Ferri N, Ancora D, De Pasquale F, Vignola G, Torricelli A. Reliability of fNIRS for noninvasive monitoring of brain function and emotion in sheep.. Sci Rep 2020 Sep 7;10(1):14726.
- Park JL, Dudchenko PA, Donaldson DI. Navigation in Real-World Environments: New Opportunities Afforded by Advances in Mobile Brain Imaging.. Front Hum Neurosci 2018;12:361.
- Végh T. Cerebral Oximetry in General Anaesthesia.. Turk J Anaesthesiol Reanim 2016 Oct;44(5):247-249.
- Steppan J, Hogue CW Jr. Cerebral and tissue oximetry.. Best Pract Res Clin Anaesthesiol 2014 Dec;28(4):429-39.
- Poller C, Hopster K, Rohn K, Kästner SB. Evaluation of contact heat thermal threshold testing for standardized assessment of cutaneous nociception in horses - comparison of different locations and environmental conditions.. BMC Vet Res 2013 Jan 8;9:4.
- Hoffmann MV, Kästner SB, Kietzmann M, Kramer S. Contact heat thermal threshold testing in beagle dogs: baseline reproducibility and the effect of acepromazine, levomethadone and fenpipramide.. BMC Vet Res 2012 Oct 30;8:206.
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