A 200-Channel Imaging System of Muscle Oxygenation Using CW Near-Infrared Spectroscopy

Masatsugu NIWAYAMA, Katsuyuki YAMAMOTO, Daisuke KOHATA, Kosuke HIRAI, Nobuki KUDO, Takafumi HAMAOKA, Ryotaro KIME, Toshihito KATSUMURA

Summary :

We have developed a 200-channel imaging system that enables measurement of changes in oxygenation and blood volume and that covers a wider area (45 cm 15 cm) than that covered by conventional systems. This system consisted of 40 probes of five channels, a light-emitting diode (LED) driver, multiplexers and a personal computer. Each probe was cross-shaped and consisted of an LED, five photo diodes, and a current-to-voltage (I-V) converter. Lighting of the LEDs and acquisition of 200-channel data were time-multiplexed. The minimum data acquisition time for 200 channels, including the time required for calculation of oxygenation and monitoring of a few traces of oxygenation on a computer display, was about 0.2 s. We carried out exercise tests and measured the changes in oxy- and deoxy-hemoglobin concentrations in the thigh. Working muscles in exercises could be clearly imaged, and spatio-temporal changes in muscle oxygenation during exercise and recovery were also shown. These results demonstrated that the 200-channel imaging system enables observation of the distribution of muscle metabolism and localization of muscle function.

• Publication: IEICE TRANSACTIONS on Information Vol.E85-D No.1 pp.115-123
• Publication Date: 2002/01/01
• Type of Manuscript: Special Section PAPER (Special Issue on Measurements and Visualization Technology of Biological Information)
• Category: Optical Imaging

Authors

Masatsugu NIWAYAMA
Katsuyuki YAMAMOTO
Daisuke KOHATA
Kosuke HIRAI
Nobuki KUDO
Takafumi HAMAOKA
Ryotaro KIME
Toshihito KATSUMURA

Keyword

near-infrared spectroscopy,  tissue oxygenation,  skeletal muscle,  functional imaging