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Dependence of brain intravoxel incoherent motion perfusion parameters on the cardiac cycle

Christian Federau1, Patric Hagmann, Philippe Maeder

  • 1Centre Hospitalier Universitaire Vaudois (CHUV) and University of Lausanne, Lausanne, Switzerland.

Plos One
|September 12, 2013
PubMed

Insights

Intravoxel Incoherent Motion (IVIM) MRI reveals brain microvasculature pulsatility. Key parameters D* and fD* are higher during systole than diastole, demonstrating non-invasive measurement of blood flow variations.

Area of Science:

  • Medical Imaging
  • Physiology
  • Neuroscience

Background:

  • Intravoxel Incoherent Motion (IVIM) MRI is an emerging technique for measuring microvascular perfusion.
  • Physiological influences on IVIM parameters like D*, f, and fD* are not fully understood.
  • Blood flow speed, a key determinant of D* and fD*, is known to vary with the cardiac cycle.

Purpose of the Study:

  • To investigate the impact of the cardiac cycle on IVIM perfusion parameters in the healthy human brain.
  • To test the hypothesis that D* and fD* vary between systole and diastole due to blood speed changes.

Main Methods:

  • An extended IVIM model incorporating time-dependent D* (D*(t)) was developed.
  • The modified IVIM model was applied to MRI data from the healthy human brain.
  • Comparison of IVIM parameters between systolic and diastolic phases of the cardiac cycle.

Main Results:

  • The pseudo-diffusion coefficient (D*) and flow-related parameter (fD*) were significantly higher during systole compared to diastole.
  • The diffusion coefficient (D) and perfusion fraction (f) showed no significant variation between systole and diastole.
  • These findings provide non-invasive evidence of microvascular pulsatility in the brain.

Conclusions:

  • The cardiac cycle significantly influences IVIM parameters D* and fD* in the healthy brain.
  • The time-dependent IVIM model successfully captures the pulsatility of the brain's microvasculature.
  • This study enhances the physiological understanding of IVIM MRI and its application in neuroimaging.

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