Document Detail

Effects of turbulence on signal intensity in gradient echo images.
MedLine Citation:
PMID:  3170139     Owner:  NLM     Status:  MEDLINE    
Although the appearance of laminar vascular flow in magnetic resonance (MR) images has been characterized, there is no general agreement about the effect of turbulent flow on MR signal intensity. This study uses a fast scan gradient echo pulse sequence to evaluate nonpulsatile turbulent flow in two different models. The first model simulated flow in normal vascular structure. It generated nonpulsatile, laminar and turbulent flow in straight, smooth-walled Plexiglas tubes. The second model simulated flow through a vascular stenosis. It generated nonpulsatile, laminar, and turbulent flow through an orifice. Velocities and flow rates ranged from low physiologic to well above the physiologic range (velocity = .3 to 280 cm/second, flow rate from .15 to 40 L/minute). Transition from laminar to turbulent flow was observed with dye streams. Turbulent flow in straight, smooth-walled vessels was not associated with a decrease in MR signal intensity even at the highest velocities and flow rates studied. The transition from laminar to turbulent flow through an orifice is not associated with a decrease in gradient echo signal intensity. As the intensity of the turbulent flow increases, however, there is a threshold above which signal intensity decreases linearly as turbulence increases (r = .97). This study suggests that flow in normal vascular structures should not be associated with decreased signal intensity in gradient echo images. Turbulent flow through areas such as valves, valvular lesions or vascular stenoses, may be associated with a decrease in gradient echo signal intensity.
A J Evans; R A Blinder; R J Herfkens; C E Spritzer; D O Kuethe; E K Fram; L W Hedlund
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Investigative radiology     Volume:  23     ISSN:  0020-9996     ISO Abbreviation:  Invest Radiol     Publication Date:  1988 Jul 
Date Detail:
Created Date:  1988-11-14     Completed Date:  1988-11-14     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0045377     Medline TA:  Invest Radiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  512-8     Citation Subset:  IM    
Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710.
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MeSH Terms
Blood Flow Velocity
Blood Physiological Phenomena*
Blood Vessels / physiology
Constriction, Pathologic / physiopathology
Magnetic Resonance Imaging* / methods
Models, Anatomic
Models, Cardiovascular
Vascular Diseases / physiopathology

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