title: Phase contrast MRI quantification of pulsatile volumes of brain arteries, veins, and cerebrospinal fluids compartments: repeatability and physiological interactions.
abstract: OBJECTIVE
  To study measurement repeatability and physiological determinants on measurement stability for phase contrast MRI (PC-MRI) measurements of cyclic volume changes (ΔV) of brain arteries, veins, and cerebrospinal fluid (CSF) compartments.
  
  
  METHODS
  Total cerebral blood flow (tCBF), total internal jugular flow (tJBF) and spinal CSF flow at C2-C3 level and CSF in the aqueduct was measured using five repetitions in 20 healthy subjects. After subtracting net flow, waveforms were integrated to calculate ΔV of arterial, venous, and cerebrospinal fluid compartments. The intraclass correlation coefficient (ICC) was used to measure repeatability. Systematic errors were investigated by a series of phantom measurements.
  
  
  RESULTS
  For ΔV calculated from tCBF, tJBF and both CSF waveforms, the ICC was ≥0.85. ΔV from the tCBF waveform decreased linearly between repetitions (P = 0.012). Summed CSF and venous volume being shifted out from the cranium was correlated with ΔV calculated from the tCBF waveform (r = 0.75; P < 0.001). Systematic errors increased at resolutions <4 pixels per diameter.
  
  
  CONCLUSIONS
  Repeatability of ΔV calculated from tCBF, tJBF, and CSF waveforms allows useful interpretations. The subject's time in the MR system and imaging resolution should be considered when interpreting volume changes. Summed CSF and venous volume changes was associated with arterial volume changes.
authors.affiliation: Department of Radiation Sciences, Umeå University, Umeå, Sweden. anders.wahlin@radfys.umu.se
authors.forename: Anders
authors.initials: A
authors.lastname: Wåhlin
authors.forename: Khalid
authors.initials: K
authors.lastname: Ambarki
authors.forename: Jón
authors.initials: J
authors.lastname: Hauksson
authors.forename: Richard
authors.initials: R
authors.lastname: Birgander
authors.forename: Jan
authors.initials: J
authors.lastname: Malm
authors.forename: Anders
authors.initials: A
authors.lastname: Eklund
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D001921:Brain / Q000098:blood supply* / Q000502:physiology*; D002555:Cerebrospinal Fluid / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology; D015203:Reproducibility of Results