Cardiorespiratory noise correction improves the ASL signal

Mahlega S. Hassanpour, Qingfei Luo, W. Kyle Simmons, Justin S. Feinstein, Martin P. Paulus, Wen Ming Luh, Jerzy Bodurka, Sahib S. Khalsa

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Cardiorespiratory fluctuations such as changes in heart rate or respiration volume influence the temporal dynamics of cerebral blood flow (CBF) measurements during arterial spin labeling (ASL) fMRI. This “physiological noise” can confound estimates of resting state network activity, and it may lower the signal-to-noise ratio of ASL during task-related experiments. In this study we examined several methods for minimizing the contributions of both synchronized and non-synchronized physiological noise in ASL measures of CBF, by combining the RETROICOR approach with different linear deconvolution models. We evaluated the amount of variance in CBF that could be explained by each method during physiological rest, in both resting state and task performance conditions. To further demonstrate the feasibility of this approach, we induced low-frequency cardiorespiratory deviations via peripheral adrenergic stimulation with isoproterenol, and determined how these fluctuations influenced CBF, before and after applying noise correction. By suppressing physiological noise, we observed substantial improvements in the signal-to-noise ratio at the individual and group activation levels. Our results suggest that variations in cardiac and respiratory parameters can account for a large proportion of the variance in resting and task-based CBF, and indicate that regressing out these non-neuronal signal variations improves the intrinsically low signal-to-noise ratio of ASL. This approach may help to better identify and control physiologically driven activations in ASL resting state and task-based analyses.

Original languageEnglish
Pages (from-to)2353-2367
Number of pages15
JournalHuman Brain Mapping
Issue number6
StatePublished - Jun 2018
Externally publishedYes


  • arterial spin labeling
  • cardiorespiratory stimulation
  • cerebral blood flow
  • non-synchronized noise
  • physiological noise reduction
  • synchronized noise


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