Article Figures & Data
Figures
- FIG 1.
A, Schematic overview of the MR imaging setup. The subject, in a supine position, was instructed to breath guided by a video on an external display. Thoracic circumference respiratory bellows were used to monitor breathing. B, High-resolution, whole-spine images were obtained using a 3-block sagittal 3D T2 SPACE sequence, and flow measurements were acquired with a 2D phase-contrast MR imaging sequence at 5 locations along the spinal canal: C2/C3, T2/T3, T6/T7, T10/T11, and L1/L2. At each level, the ROIs corresponding to the SSAS were drawn manually (yellow shaded regions). Images shown correspond to subject 3.
- FIG 2.
Results for subject 1. A, Map of flow velocity in centimeters per second across each section at mid-inhalation (left column) and mid-expiration (right column). B, Plot of the flow rate in milliliters per second across each section through the respiratory cycle. C, Plot of temporally filtered flow rate. D, Change in fluid volume through the respiratory cycle with respect to the start of inhalation for each spinal level. E, Amount of fluid moved between adjacent levels (stroke volume) for each section. F, Net volume increase or decrease at each level during inhalation. G, Net volume increase or decrease during expiration.
- FIG 3.
Selected results for subjects 1–6. C, D, E/G correspond to those in Fig 2.
Tables
Interindividual variations in stroke volume and in net volume increase during expiration at each spinal level
Section Stroke Volume (mL) Net Volume Increase during Expiration (mL) Min Mean Max Segment Min Mean Max C2/C3 0.54 0.99 1.66 C2/C3–T2/T3 –1.54 –0.29 0.17 T2/T3 0.62 1.37 3.07 T2/T3–T6/T7 –0.28 0.23 0.62 T6/T7 0.38 1.14 2.58 T6/T7–T10/T11 –0.51 –0.23 0.02 T10/T11 0.57 1.54 2.88 T10/T11–L1/L2 –0.49 0.09 0.57 L1/L2 0.76 1.52 3.07 L1/T2–L5/S1 0.76 1.52 3.07 Note:—Min indicates minimum; Max, maximum.
