Influence of Spatial Resolution in Three-dimensional Cine Phase Contrast Magnetic Resonance Imaging on the Accuracy of Hemodynamic Analysis

Abstract

Introduction:We aim to elucidate the effect of spatial resolution of three-dimensional cine phase contrast magnetic resonance (3D cine PC MR) imaging on the accuracy of the blood flow analysis, and examine the optimal setting for spatial resolution using flow phantoms.Materials and Methods:The flow phantom has five types of acrylic pipes that represent human blood vessels (inner diameters: 15, 12, 9, 6, and 3 mm). The pipes were fixed with 1% agarose containing 0.025 mol/L gadolinium contrast agent. A blood-mimicking fluid with human blood property values was circulated through the pipes at a steady flow. Magnetic resonance (MR) images (three-directional phase images with speed information and magnitude images for information of shape) were acquired using the 3-Tesla MR system and receiving coil. Temporal changes in spatially-averaged velocity and maximum velocity were calculated using hemodynamic analysis software. We calculated the error rates of the flow velocities based on the volume flow rates measured with a flowmeter and examined measurement accuracy.Results:When the acrylic pipe was the size of the thoracicoabdominal or cervical artery and the ratio of pixel size for the pipe was set at 30% or lower, spatially-averaged velocity measurements were highly accurate. When the pixel size ratio was set at 10% or lower, maximum velocity could be measured with high accuracy. It was difficult to accurately measure maximum velocity of the 3-mm pipe, which was the size of an intracranial major artery, but the error for spatially-averaged velocity was 20% or less.Conclusions:Flow velocity measurement accuracy of 3D cine PC MR imaging for pipes with inner sizes equivalent to vessels in the cervical and thoracicoabdominal arteries is good. The flow velocity accuracy for the pipe with a 3-mm-diameter that is equivalent to major intracranial arteries is poor for maximum velocity, but it is relatively good for spatially-averaged velocity.

Accuracy of the Flow Velocity and Three-directional Velocity Profile Measured with Three-dimensional Cine Phase-contrast MR Imaging: Verification on Scanners from Different Manufacturers

“…Previously published paper reported that the error rate of the maximum velocity is less than 10% when the ratio of the pixel size to the inner diameter is less than 10%. 16 In this experiment, the voxel size was 10% of the diameter (voxel size, 0.7 mm; diameter, 7 mm), but the error of the maximum velocities of some scanners exceeded 10%. It is estimated that the measurement error of the maximum flow velocity would be less than 10% if we had used optimum conditions including imaging parameters, receiver coil, imaging position, and so on.…”

Clinical Application of 4D Flow MR Imaging for the Abdominal Aorta

“…However, it was greater than 40% for a pixel size of 1.0 mm. 29 As the standard spatial resolution for current 4D flow MRI is around 1.0 mm, errors of 20%-40% should be taken into account in the flowmetry of tiny vessels.…”

Assessing the Risk of Intracranial Aneurysm Rupture Using Morphological and Hemodynamic Biomarkers Evaluated from Magnetic Resonance Fluid Dynamics and Computational Fluid Dynamics

“…On the other hand, MRFD needs lesser time and personnel effort despite its low resolution compared with CFD in assessing arteries with small caliber. 32 It is reflected that MRFD is more feasible in the clinical setting whereas CFD would be appropriate for the experimental and research setting. In the present study, the statistically significant hemodynamic biomarkers between the ruptured and unruptured groups showed the same pattern in both MRFD and CFD-based results.…”