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Characterization of flow emerging from a stenosis using MRI
Author(s) -
Gach H. Michael,
Lowe Irving J.
Publication year - 1998
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910400409
Subject(s) - laminar flow , turbulence , reynolds number , flow (mathematics) , stenosis , physics , mechanics , open channel flow , eddy , nuclear magnetic resonance , medicine , radiology
MRI ultra‐fast imaging techniques are used to characterize flow emerging from streamlined and abrupt stenoses inside cylindrical channels. Reattachment lengths of the shear boundary to the channel wall are measured using rotating ultra‐fast imaging sequence (RUFIS) in‐flow imaging. Velocity profiles of flow are created using velocity (sine and cosine)‐encoded RUFIS sequences. The sine‐encoded images permit one to identify reverse flow (i.e., eddies) that arise within the region of flow reattachment. The ratios of peak velocities (downstreamhpstream of the stenosis) derived from the cosine‐encoded images are used to identify the transition from the laminar to the turbulent regimen. Based on these experiments, the transition from the laminar to turbulent regimen occurs at a stenotic Reynolds Number of 350, whereas fully developed turbulence occurs at a stenotic Reynolds Number of 2600. These results are compared with the results from invasive studies.