A uniplanar three-axis gradient set for in vivo magnetic resonance microscopy.
We present an optimized uniplanar magnetic resonance gradient design specifically tailored for MR imaging applications in developmental biology and histology. Uniplanar gradient designs sacrifice gradient uniformity for high gradient efficiency and slew rate, and are attractive for surface imaging applications where open access from one side of the sample is required. However, decreasing the size of the uniplanar gradient set presents several unique engineering challenges, particularly for heat dissipation and thermal insulation of the sample from gradient heating. We demonstrate a new three-axis, target-field optimized uniplanar gradient coil design that combines efficient cooling and insulation to significantly reduce sample heating at sample-gradient distances of less than 5mm. The instrument is designed for microscopy in horizontal bore magnets. Empirical gradient current efficiencies in the prototype coils lie between 3.75G/cm/A and 4.5G/cm/A with current and heating-limited maximum gradient strengths between 235G/cm and 450G/cm at a 2% duty cycle. The uniplanar gradient prototype is demonstrated with non-linearity corrections for both high-resolution structural imaging of tissue slices and for long time-course imaging of live, developing amphibian embryos in a horizontal bore 7T magnet.
Demyanenko
Andrey V
AV
Division of Biology, California Institute of Technology, 2A Broad 114-96, 1200 E California Blvd., Pasadena, CA 91125, USA.
Zhao
Lin
L
Kee
Yun
Y
Nie
Shuyi
S
Fraser
Scott E
SE
Tyszka
J Michael
JM
D000465:Algorithms; D000818:Animals; D001921:Brain / Q000648:ultrastructure; D004574:Electromagnetic Fields; D004622:Embryo, Mammalian / Q000648:ultrastructure; D004625:Embryo, Nonmammalian / Q000648:ultrastructure; D006358:Hot Temperature; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D051379:Mice; D008810:Mice, Inbred C57BL; D008853:Microscopy / Q000295:instrumentation*; D013696:Temperature; D014982:Xenopus laevis