Quantifying the influence of respiration and cardiac pulsations on cerebrospinal fluid dynamics using real-time phase-contrast MRI.
To validate a real-time phase contrast magnetic resonance imaging (RT-PCMRI) sequence in a controlled phantom model, and to quantify the relative contributions of respiration and cardiac pulsations on cerebrospinal fluid (CSF) velocity at the level of the foramen magnum (FM).



To validate the 3T MRI techniques, in vitro studies used a realistic model of the spinal subarachnoid space driven by pulsatile flow waveforms mimicking the respiratory and cardiac components of CSF flow. Subsequently, CSF flow was measured continuously during 1-minute RT-PCMRI acquisitions at the FM while healthy subjects (N = 20) performed natural breathing, deep breathing, breath-holding, and coughing. Conventional cardiac-gated PCMRI was obtained for comparison. A frequency domain power ratio analysis determined the relative contribution of respiration versus cardiac ([r/c]) components of CSF velocity.



In vitro studies demonstrating the accuracy of RT-PCMRI within 5% of input values showed that conventional PCMRI measures only the cardiac component of CSF velocity (0.42 ± 0.02 cm/s), averages out respiratory effects, and underestimates the magnitude of CSF velocity (0.96 ± 0.07 cm/s). In vivo RT-PCMRI measurements indicated the ratio of respiratory to cardiac velocity pulsations averaged over all subjects as [r/c = 0.14 ± 0.27] and [r/c = 0.40 ± 0.47] for natural and deep breathing, respectively. During coughing, the peak CSF velocity increased by a factor of 2.27 ± 1.40.



RT-PCMRI can noninvasively measure instantaneous CSF velocity driven by cardiac pulsations, respiration, and coughing in real time. A comparable contribution of respiration and cardiac pulsations on CSF velocity was found during deep breathing but not during natural breathing.



1 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:431-439.
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
Selda
S
Yildiz
Department of Mechanical Engineering, Conquer Chiari Research Center, University of Akron, Akron, Ohio, USA.
Suraj
S
Thyagaraj
MR R&D Collaborations, Siemens Healthcare, Columbus, Ohio, USA.
Ning
N
Jin
MR R&D Collaborations, Siemens Healthcare, Atlanta, Georgia, USA.|Department of Radiology, Emory University, Atlanta, Georgia, USA.
Xiaodong
X
Zhong
Department of Mechanical Engineering, Conquer Chiari Research Center, University of Akron, Akron, Ohio, USA.
Soroush
S
Heidari Pahlavian
Department of Biological Engineering, University of Idaho, Moscow, Idaho, USA.
Bryn A
BA
Martin
Department of Mechanical Engineering, Conquer Chiari Research Center, University of Akron, Akron, Ohio, USA.
Francis
F
Loth
Department of Radiology & Imaging Sciences and Biomedical Engineering, Emory University, Atlanta, Georgia, USA.
John
J
Oshinski
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
Karim G
KG
Sabra
D000328:Adult; D002555:Cerebrospinal Fluid; D003198:Computer Simulation; D003287:Contrast Media; D005260:Female; D005539:Foramen Magnum; D064368:Healthy Volunteers; D006321:Heart / Q000000981:diagnostic imaging*; D006339:Heart Rate; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008858:Microscopy, Phase-Contrast; D008875:Middle Aged; D019047:Phantoms, Imaging; D011673:Pulsatile Flow; D015203:Reproducibility of Results; D012119:Respiration; D012815:Signal Processing, Computer-Assisted; D012984:Software; D013346:Subarachnoid Space; D016683:Supine Position; D055815:Young Adult
D003287:Contrast Media
CSF flow velocity; cardiac; cerebrospinal fluid; coughing; real-time phase contrast MRI; respiration