CSF Flow through the Upper Cervical Spinal Canal in Chiari I Malformation

PCMR axial flow images from diastole (left column) and systole (right column) in each of the 4 regions in a patient with tonsilar ectopia. Systolic flow (away from the head) has a positive (bright) signal intensity, and diastolic flow (toward the head) has a dark signal intensity. Flow patterns have greater inhomogeneity and higher velocities as the distance from the foramen magnum increases. PDVs in this patient are respectively 3.7, 2.9, 7.0, and 8.0 cm/s in regions 1 though 4; PSVs are 5.2, 5.6, 6.8, and 10.4 cm/s. In systolic flow images in regions 3 and 4, paradoxical negative signal intensity indicative of aliased flow is noted in the regions of high positive flow.

PDV and PSV at regions 1 through 4 in 17 patients with multilevel CSF flow studies. The average PSV (black line) increases progressively over the 4 regions. The average PDV (black line) increases over the first 3 regions. Error bars display 1 SD.

PSVs and PDVs in 14 patients with and 4 without tonsillar ectopia. The black lines and error bars show respectively the mean and SD. The effect of level on peak velocity differs for the 2 groups.

PSVs and PDVs for patients 10 years of age or younger and patients older than 10 years of age plotted by region. Average PSV (black line) is faster in the younger patients. Error bars show an SD. The gray lines and error bars show the mean and SD.