Theoretical evaluation of accuracy in position and size of brain activity obtained by near-infrared topography

Hiroshi Kawaguchi, Toshiyuki Hayashi, Toshinori Kato, Eiji Okada

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Near-infrared (NIR) topography can obtain a topographical distribution of the activated region in the brain cortex. Near-infrared light is strongly scattered in the head, and the volume of tissue sampled by a source-detector pair on the head surface is broadly distributed in the brain. This scattering effect results in poor resolution and contrast in the topographic image of the brain activity. In this study, a one-dimensional distribution of absorption change in a head model is calculated by mapping and reconstruction methods to evaluate the effect of the image reconstruction algorithm and the interval of measurement points for topographic imaging on the accuracy of the topographic image. The light propagation in the head model is predicted by Monte Carlo simulation to obtain the spatial sensitivity profile for a source-detector pair. The measurement points are one-dimensionally arranged on the surface of the model, and the distance between adjacent measurement points is varied from 4 mm to 28 mm. Small intervals of the measurement points improve the topographic image calculated by both the mapping and reconstruction methods. In the conventional mapping method, the limit of the spatial resolution depends upon the interval of the measurement points and spatial sensitivity profile for source-detector pairs. The reconstruction method has advantages over the mapping method which improve the results of one-dimensional analysis when the interval of measurement points is less than 12 mm. The effect of overlapping of spatial sensitivity profiles indicates that the reconstruction method may be effective to improve the spatial resolution of a two-dimensional reconstruction of topographic image obtained with larger interval of measurement points. Near-infrared topography with the reconstruction method potentially obtains an accurate distribution of absorption change in the brain even if the size of absorption change is less than 10 mm.

Original languageEnglish
Pages (from-to)2753-2765
Number of pages13
JournalPhysics in Medicine and Biology
Volume49
Issue number12
DOIs
Publication statusPublished - 2004 Jun 21

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Topography
brain
Brain
topography
Infrared radiation
evaluation
intervals
Head
Computer-Assisted Image Processing
Detectors
sensitivity
detectors
profiles
spatial resolution
Light
Light propagation
cortexes
dimensional analysis
image reconstruction
Image reconstruction

ASJC Scopus subject areas

  • Biomedical Engineering
  • Physics and Astronomy (miscellaneous)
  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

Cite this

Theoretical evaluation of accuracy in position and size of brain activity obtained by near-infrared topography. / Kawaguchi, Hiroshi; Hayashi, Toshiyuki; Kato, Toshinori; Okada, Eiji.

In: Physics in Medicine and Biology, Vol. 49, No. 12, 21.06.2004, p. 2753-2765.

Research output: Contribution to journalArticle

Kawaguchi, Hiroshi ; Hayashi, Toshiyuki ; Kato, Toshinori ; Okada, Eiji. / Theoretical evaluation of accuracy in position and size of brain activity obtained by near-infrared topography. In: Physics in Medicine and Biology. 2004 ; Vol. 49, No. 12. pp. 2753-2765.
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