Pressure modulation algorithm to separate cerebral hemodynamic signals from extracerebral artifacts

Wesley B. Baker, Ashwin B. Parthasarathy, Tiffany S. Ko, David R. Busch, Kenneth Abramson, Shih Yu Tzeng, Rickson C. Mesquita, Turgut Durduran, Joel H. Greenberg, David K. Kung, Arjun G. Yodh

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


We introduce and validate a pressure measurement paradigm that reduces extracerebral contamination from superficial tissues in optical monitoring of cerebral blood flow with diffuse correlation spectroscopy (DCS). The scheme determines subject-specific contributions of extracerebral and cerebral tissues to the DCS signal by utilizing probe pressure modulation to induce variations in extracerebral blood flow. For analysis, the head is modeled as a two-layer medium and is probed with long and short source-detector separations. Then a combination of pressure modulation and a modified Beer-Lambert law for flow enables experimenters to linearly relate differential DCS signals to cerebral and extracerebral blood flow variation without a priori anatomical information. We demonstrate the algorithm's ability to isolate cerebral blood flow during a finger-tapping task and during graded scalp ischemia in healthy adults. Finally, we adapt the pressure modulation algorithm to ameliorate extracerebral contamination in monitoring of cerebral blood oxygenation and blood volume by near-infrared spectroscopy.

Original languageEnglish (US)
Article number35004
Issue number3
StatePublished - Jul 1 2015
Externally publishedYes


  • cerebral blood flow monitoring
  • diffuse correlation spectroscopy
  • functional brain imaging
  • near-infrared spectroscopy
  • stroke

ASJC Scopus subject areas

  • Neuroscience (miscellaneous)
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging


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