Effects of turbulence on signal intensity in gradient echo images.


Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Evans, AJ; Blinder, RA; Herfkens, RJ; Spritzer, CE; Kuethe, DO; Fram, EK; Hedlund, LW

Published Date

  • July 1988

Published In

Volume / Issue

  • 23 / 7

Start / End Page

  • 512 - 518

PubMed ID

  • 3170139

Pubmed Central ID

  • 3170139

International Standard Serial Number (ISSN)

  • 0020-9996

Digital Object Identifier (DOI)

  • 10.1097/00004424-198807000-00006


  • eng

Conference Location

  • United States