Article Figures & Data
Figures
- Fig 1.
Diagram of the setup used in phantom studies for evaluating CPC and RPC. Tubing was connected to a computer-controlled flow pump. The tubing was looped around a cubic MR imaging QA phantom and situated in the horizontal plane of the scanner along the z-axis.
- Fig 2.
Average measurements of constant velocities obtained with the RPC (A) and CPC (B) acquisitions compared with actual velocities. The solid line represents unity. Error bars are SDs.
- Fig 3.
Error (A) and coefficient of variation (B) of peak velocity measurements in a constant flow phantom calculated from the RPC and CPC acquisitions. Actual peak velocities ranged from 0.8 to 50.6 cm/s.
- Fig 4.
Velocity (± SD) calculated from the CPC (A) and RPC (B) acquisition data plotted as a function of time for a sinusoidal flow rate of 1 mL/s at 60 beats per minute. The RPC data were acquired with 64 projections and 2 vps. The CPC data were acquired with 128 phase-encoding values and a ½ FOV. Three scans were obtained with each acquisition and error bars are shown. For each set of data, a sinusoidal curve of the form a + b × sin[2π(t − t0)] was fitted.
- Fig 5.
Phase images of CSF acquired at the level of the foramen magnum in 1 healthy volunteer with the CPC (TR/TE = 23.0/6.0 ms) (A) and RPC (TR/TE = 14.8/9.2 ms) (B) acquisitions. Arrows point to the area of the subarachnoid space at the level of the foramen magnum.
- Fig 6.
CSF flow over the R-R interval in the foramen magnum of 1 healthy volunteer as measured with the RPC and CPC acquisitions.
Tables
- Table 1:
Average and peak velocities at the zenith and nadir of a sinusoidal waveform measured in a phantom with the RPC and CPC acquisitions
RPCa CPCa Absolute Difference Average velocity at zenith (cm/s) 6.5 ± 0.1 6.4 ± 1.2 0.1 Average velocity at nadir (cm/s) 1.8 ± 0.7 2.0 ± 1.1 0.2 Peak velocity at zenith (cm/s) 11.5 ± 0.6 10.2 ± 0.9 1.3 Peak velocity at nadir (cm/s) 4.3 ± 0.4 5.0 ± 0.6 0.7 Average 0.6 ± 0.6 -
a Mean values ± SDs.
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- Table 2:
Peak systolic and diastolic CSF velocities in 5 human volunteers at the level of the foramen magnum defined in sagittal images by the tip of the clivus anteriorly and the occipital bone posteriorly
RPC CPC Absolute Difference Systolic peak velocity (cm/s) Volunteer 1 2.2 2.4 0.2 Volunteer 2 4.3 4.0 0.3 Volunteer 3 3.7 3.6 0.1 Volunteer 4 2.1 2.2 0.1 Volunteer 5 2.0 2.2 0.2 Averagea 2.9 ± 1.1 2.9 ± 0.9 0.2 ± 0.1 Diastolic peak velocity (cm/s) Volunteer 1 1.0 1.1 0.1 Volunteer 2 0.9 1.0 0.1 Volunteer 3 1.6 1.4 0.2 Volunteer 4 0.4 0.8 0.4 Volunteer 5 0.8 0.8 0.0 Averagea 0.9 ± 0.4 1.0 ± 0.3 0.2 ± 0.2 -
a Mean values ± SDs.
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