Quantitative evaluation of frequency domain measurements in high density diffuse optical tomography

Research output: Contribution to journalArticlepeer-review


Colleges, School and Institutes

External organisations

  • Department of Radiology, Washington University School of Medicine, 4525 Scott Avenue, St. Louis, MO, 63110, USA


Significance: High Density Diffuse Optical Tomography (HD-DOT) as applied in fNIRS is largely limited to continuouswave (CW) data. Using a single modulation frequency, frequency domain (FD) HD-DOT has recently demonstratedbetter localisation of focal activation as compared to CW data. This study shows that combining CW and FDmeasurements and multiple modulation frequencies increases imaging performance in fNIRS.

Aim: This work evaluates the benefits of multiple modulation frequencies, combining different frequencies as well asCW data in fNIRS HD-DOT.

Approach: A layered model was used, with activation occurring within a cortex layer. CW and FD measurementswere simulated at 78, 141 and 203 MHz with and without noise. The localization error, full width half maximum andeffective resolution were evaluated.

Results: Across the average of the three metrics, at 141 MHz, FD performed 8.4% better than CW and the combinationof CW and FD was 21.7% better than CW. FD measurements at 203 MHz performed 5% better than 78 MHz.Moreover, the three combined modulation frequencies of FD and CW performed up to 3.92% better than 141 MHzalone.

Conclusions: This work shows that combining CW&FD measurements offer better performance than FD alone, withhigher modulation frequencies increasing accuracy. Combining CW&FD measurements at multiple modulation frequenciesyields the best overall performance.


Original languageEnglish
Article number056001
Number of pages18
JournalJournal of Biomedical Optics
Issue number5
Publication statusPublished - 4 May 2021


  • frequency domain, modulation frequency, near-infrared spectroscopy, diffuse optical tomography, brain imaging, resolution