ADAPTIVE TECHNIQUES FOR MR IMAGING OF MOVING STRUCTURES

Project: Research project

Project Details

Description

Motion-induced blurring and artifact phenomena continue to limit the
potential of MR imaging in a variety of organ systems and clinical
settings. These difficulties have become accentuated even as imaging
systems have been improved: increases in available signal-to-noise are
almost inevitably traded for improved spatial resolution or decreased
acquisition time, often increasing the sensitivity of imaging examinations
to the effects of motion. The importance of physiological motion is now well appreciated, though
still poorly addressed with present technology. Gross motion can be
equally problematic in many settings, and could indeed be considered to be
the source of the greatest risks associated with MRI since it the usual
motivation for the use of sedation or anesthesia in pediatric and other
patient groups. Rapid MR acquisition methods show some promise for alleviating these
problems, but they are associated with a number of tradeoffs; their future
role for addressing the problem of motion remains hypothetical. Most of
the other motion correction techniques that are currently available are
helpful for reducing artifacts, but they cannot correct motion unsharpness. This project is designed to investigate a new approach for imaging moving
objects with MRI. Mathematical operators are applied to the MR data prior
to reconstruction. These operators adaptively correct the image data for
global view-to-view tissue motion and, if desired, for bulk phase shifts
caused by intraview tissue motion. They essentially transfer the frame of
reference of the image coordinate system from the scanner tabletop to the
moving frame. The underlying hypothesis of this approach is that although
the pattern of motion is unique during any given acquisition, it often
globally similar for many volume elements in a clinically relevant field of
view. A prerequisite for such adaptive correction is detailed information about
the motion that occurs during image acquisition. One way to obtain this
information is to use specially encoded Navigator echoes, which are
interleaved into the imaging sequence. Viewed together, the adaptive methods described in this proposal point to
the development of an extremely robust imaging method, compatible with
clinically proven spin echo technology, which essentially "locks" to the
region of interest during acquisition. This could obviate the need for
sedation or anesthesia in some patient groups. Beyond the important
objective of increasing the clinical reliability of the modality, the
preliminary results suggest that the technique could provide an improved
level of detail in applications that are currently limited by the effects
of respiratory motion.
StatusFinished
Effective start/end date8/9/917/31/98

Funding

  • National Institutes of Health: $165,681.00
  • National Institutes of Health
  • National Institutes of Health: $209,229.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health

ASJC

  • Medicine(all)

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