Brain parenchyma motion: measurement with cine echo-planar MR imaging.
With echo-planar magnetic resonance (MR) imaging, the authors measured the intrinsic pulsatile motion of brain parenchyma. Phase-sensitive, electrocardiography-gated, two-dimensional cine images were acquired throughout the cardiac cycle by using a spin-echo, blipped echo-planar MR pulse sequence. Transverse and coronal planes were obtained in 14 healthy volunteers. Corrections were made for gross head motion. Brain motion consisted of a rapid displacement in systole, with a slow diastolic recovery. The motion occurred chiefly in the cephalocaudal and lateral directions; the anteroposterior motions were relatively small. Cephalocaudal velocities increase with proximity to the foramen magnum. The lateral motion is mainly a compressive motion of the thalami. Brain parenchymal velocities were as high as 2 mm/sec caudally in the brain stem and 1.5 mm/sec medially in the thalami. Net parenchymal excursions were at most 0.5 mm. Phase-based echo-planar velocity measurements agreed well with echo-planar Fourier velocity zeugmatography measurements and were consistent with reported values. Velocity mapping with echo-planar imaging offers a rapid and flexible method of assessing the pulsation velocities of the human brain.
Poncelet
B P
BP
MGH-NMR Center, Department of Radiology, Massachusetts General Hospital, Charlestown 02129.
Wedeen
V J
VJ
Weisskoff
R M
RM
Cohen
M S
MS
D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D017352:Echo-Planar Imaging; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009040:Motion Pictures; D009068:Movement; D013382:Subtraction Technique