MR IMAGING AND COMPUTER RECONSTRUCTION OF FLOW PATTERNS

  • Buonocore, Michael H, (PI)

Project: Research project

Description

MRI velocity encoded phase imaging has the potential for rapid, accurate
and precise determination of 3-D blood flow patterns. It is believed that
if the capability to display and quantitate these flow patterns were
readily available, routine diagnostic utilization would emerge. immediate
diagnostic applications include improved measurement of traditional
cardiovascular parameters such as cardiac output, stroke volume,
regurgitant fractions, pressure gradients, and quantitative assessment of
vascular aneurysms and malformations. A new application is the measurement
of total left and right coronary artery flow from measurements of velocity
in the ascending aorta, aortic root, and proximal portions of these
vessels. The broad, long term objective of the application is the development of
rapid, accurate and precise MR imaging techniques for reconstruction and
visualization of 3-D blood flow patterns. The application will develop (1)
cardiac gated, limited field of view (FOV) 3-D velocity encoded pulse
sequences for generation of velocity data, and (2) algorithms based on
fluid mechanics for reconstruction and display of the flow patterns.
Selective RF signal suppression or excitation will be used to allow
collection of 3-D data with a small FOV and small number of phase encode
steps in each direction. Accuracy and precision of the velocity data will
be achieved by adapting 2-D pulse sequence methodology. Time-coded
streamlines will be used to visualize the flow patterns. Fluid dynamics
conservation laws, vessel boundary, and constant flux constraints will be
imposed on the 3-D velocity data to significantly improve the internal
consistency of the data and the accuracy and precision of reconstructed
streamlines. The new techniques will be applied to the measurement of coronary artery
flow. While several groups have developed optimized pulse sequences to
visualize the coronary arteries, measurement of total flow is not yet
reliable. Differences in pulse sequence design for flow measurement are
the need for (I) high temporal resolution to eliminate errors due to
pulsatility, (2) thin slices to minimize partial volume errors, and (3)
data acquisition through the entire RR interval. The 3-D pulse sequences
will measure, in a single sequence, the blood velocity in the ascending
aorta, sinuses of Valsalva leading into the coronary arteries, and within
the coronary arteries. The reconstruction algorithms will improve the
internal consistency of the velocity data and generate flow patterns that
are consistent with fluid dynamics constraints.
StatusFinished
Effective start/end date9/30/938/31/98

Funding

  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health

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Flow patterns
Coronary Vessels
Imaging techniques
Hydrodynamics
Blood
Aorta
Sinus of Valsalva
Vascular Malformations
Mechanics
Cardiac Output
Stroke Volume
Phase velocity
Aneurysm
Flow measurement
Fluid dynamics
Pressure gradient
Magnetic resonance imaging
Volume fraction
Data acquisition
Pressure

Keywords

  • Medicine(all)