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Alternative control volume geometries for measuring regurgitant flow through a valve
Eduardo Kortright1, Rui Xia, Andreas S Anayiotos
1Department of Computer Science, University of New Orleans, New Orleans, LA 70148, USA. eduardo@cs.uno.edu
Summary
Control-volume (CV) methods accurately measure reverse blood flow volume. A cylindrical CV configuration shows promise for clinical use, offering good accuracy and practical implementation benefits.
Area of Science:
- Cardiovascular Imaging and Fluid Dynamics
- Medical Physics and Biomedical Engineering
Background:
- Control-volume (CV) methods using magnetic resonance velocity-encoded cine imaging accurately measure reverse blood flow in regurgitant valves.
- Previous studies acknowledge spatial and temporal averaging effects on accuracy, but slice thickness and orientation effects remain understudied.
- Unrecognized errors in surface area calculations at CV wall intersections can impact accuracy.
Purpose of the Study:
- To systematically evaluate the impact of slice thickness and orientation on CV method accuracy for regurgitant valve flow.
- To explore novel CV configurations requiring fewer scans and assess their clinical potential.
- To identify and quantify errors associated with surface area calculations in CV methods.
Main Methods:
- A computational fluid dynamics model simulating steady flow through an orifice was employed.
- Five distinct CV configurations were evaluated for accuracy, time costs, and clinical feasibility.
- The study analyzed voxel grid alignment, slice orientation, and surface area calculation errors.
Main Results:
- CVs with basal walls showed blurring of axial velocity gradients near the orifice.
- Voxel grid alignment relative to the orifice was the primary source of inaccuracy.
- Surface area calculation errors at plane intersections caused deviations of 7-20%.
- A CV using slices parallel to the orifice plane was clinically unusable.
- A cylindrical CV configuration demonstrated good accuracy in simulations and practical potential.
Conclusions:
- Voxel grid alignment and CV configuration significantly impact the accuracy of blood flow volume measurements.
- Cylindrical CVs offer a promising balance of accuracy, efficiency, and ease of implementation for clinical use.
- Further research into optimizing CV configurations and minimizing calculation errors is warranted for improved cardiovascular flow assessment.