کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1807201 1025248 2009 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
On the effects of dephasing due to local gradients in diffusion tensor imaging experiments: relevance for diffusion tensor imaging fiber phantoms
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم فیزیک ماده چگال
پیش نمایش صفحه اول مقاله
On the effects of dephasing due to local gradients in diffusion tensor imaging experiments: relevance for diffusion tensor imaging fiber phantoms
چکیده انگلیسی

The effect of susceptibility differences between fluid and fibers on the properties of DTI fiber phantoms was investigated. Thereto, machine-made, easily producible and inexpensive DTI fiber phantoms were constructed by winding polyamide fibers of 15 μm diameter around a circular acrylic glass spindle. The achieved fractional anisotropy was 0.78±0.02. It is shown by phantom measurements and Monte Carlo simulations that the transversal relaxation time T2 strongly depends on the angle between the fibers and the B0 field if the susceptibilities of the fibers and fluid are not identical. In the phantoms, the measured T2 time at 3 T decreased by 60% for fibers running perpendicular to B0. Monte Carlo simulations confirmed this result and revealed that the exact relaxation time depends strongly on the exact packing of the fibers. In the phantoms, the measured diffusion was independent of fiber orientation. Monte Carlo simulations revealed that the measured diffusion strongly depends on the exact fiber packing and that field strength and -orientation dependencies of measured diffusion may be minimal for hexagonal packing while the diffusion can be underestimated by more than 50% for cubic packing at 3 T. To overcome these effects, the susceptibilities of fibers and fluid were matched using an aqueous sodium chloride solution (83 g NaCl per kilogram of water). This enables an orientation independent and reliable use of DTI phantoms for evaluation purposes.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Magnetic Resonance Imaging - Volume 27, Issue 4, May 2009, Pages 541–548
نویسندگان
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