Radiology, Vol 193, 477-483, Copyright © 1994 by Radiological Society of North America
Brain and cerebrospinal fluid motion: real-time quantification with M- mode MR imaging
SE Maier, CJ Hardy and FA Jolesz
Department of Radiology, Brigham and Women's Hospital, Boston, MA.
PURPOSE: To assess motion of brain parenchyma and cerebrospinal fluid (CSF)
with magnetic resonance (MR) phase imaging in real time. MATERIALS AND
METHODS: Repetitive excitation of a cylinder with two- dimensional
selective excitation followed by one-dimensional imaging along the cylinder
axis yielded profiles analogous to those of M-mode echography. Bipolar
gradients provided velocity sensitivity in an arbitrary spatial direction.
RESULTS: Brain and CSF of healthy volunteers exhibited periodic motion in
the frequency range of normal heart rate. Both brain hemispheres showed
periodic squeezing of the ventricles, with peak velocities up to 1 mm/sec
followed by a slower recoil. Superimposed on the regular displacement of
the brain stem was a slow, respiratory-related periodic shift of the
neutral position. During the Valsalva maneuver, the brain stem showed
initial caudal and subsequent cranial displacement of 2-3 mm. Coughing
produced a short swing of CSF in the cephalic direction. CONCLUSION:
Real-time MR phase imaging allows observation of non-periodic events in
brain and CSF motion.
