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Superelliptical insert gradient coil with a field‐modifying layer for breast imaging
Author(s) -
Moon Sung M.,
Craig Goodrich K.,
Rock Hadley J.,
Kim SeongEun,
Zeng Gengsheng L.,
Morrell Glen R.,
McAlpine Matthew A.,
Chronik Blaine A.,
Parker Dennis L.
Publication year - 2011
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.22639
Subject(s) - homogeneous , electromagnetic coil , materials science , temporal resolution , nuclear magnetic resonance , insert (composites) , image resolution , gradient analysis , resolution (logic) , biomedical engineering , physics , optics , computer science , medicine , artificial intelligence , composite material , quantum mechanics , ordination , machine learning , thermodynamics
Many MRI applications such as dynamic contrast‐enhanced MRI of the breast require high spatial and temporal resolution and can benefit from improved gradient performance, e.g., increased gradient strength and reduced gradient rise time. The improved gradient performance required to achieve high spatial and temporal resolution for this application may be achieved by using local insert gradients specifically designed for a target anatomy. Current flat gradient systems cannot create an imaging volume large enough to accommodate both breasts; further, their gradient fields are not homogeneous, dropping off rapidly with distance from the gradient coil surface. To attain an imaging volume adequate for bilateral breast MRI, a planar local gradient system design has been modified into a superellipse shape, creating homogeneous gradient volumes that are 182% ( G x ), 57% ( G y ), and 75% ( G z ) wider (left/right direction) than those of the corresponding standard planar gradient. Adding an additional field‐modifying gradient winding results in an additional improvement of the homogeneous gradient field near the gradient coil surface over the already enlarged homogeneous gradient volumes of the superelliptical gradients (67%, 89%, and 214% for G x , G y , and G z respectively). A prototype y ‐gradient insert has been built to demonstrate imaging and implementation characteristics of the superellipse gradient in a 3 T MRI system. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.