Open AccessFunctional near‐infrared imaging of deoxygenated hemoglobin during exercise of the finger extensor muscles using the frequency‐domain technique
Author(s) -
Maris Michael,
Gratton Enrico,
Maier John,
Mantulin William,
Chance Britton
Publication year - 1994
Publication title -
bioimaging
Language(s) - English
Resource type - Journals
eISSN - 1361-6374
pISSN - 0966-9051
DOI - 10.1002/1361-6374(199412)2:4<174::aid-bio2>3.0.co;2-q
Subject(s) - deoxygenated hemoglobin , forearm , nuclear magnetic resonance , biomedical engineering , isometric exercise , anatomy , materials science , chemistry , physics , hemoglobin , medicine , biochemistry , physical therapy
A functional image of the extensor digitorum muscle was obtained using the frequency domain spectroscopic technique with near‐infrared light. The muscle was imaged by measuring the change in phase angle of modulated waves of near‐infrared light in response to increased absorption of deoxygenated hemoglobin, which resulted from increased O 2 metabolism during arm exercise. The image was compiled from a raster scan of flexion and relaxation exercises at 95 separate points on the dorsal surface of the right forearm. Each point on the arm consisted of a complete experiment that included continuous frequency‐domain measurements of phase and intensity during rest, isotonic exercise, and recovery from exercise. Analysis consisted of a simple subtraction of the average phase angle baseline at rest from the average phase reading during steady‐state contraction of the extensor digitorum muscle. A difference array of data was then compiled from these 95 experiments to give a 2‐D density‐plot image. The image clearly demonstrates the extensor digitorum muscle in its oblique position within the density‐plot array. This experiment shows the in vivo functional imaging capability of the frequency‐resolved technique and indicates that a high degree of resolution is obtainable.