کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9587343 1393236 2005 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Measurements and modeling of long range 3He diffusion in the lung using a “slice-washout” method
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Measurements and modeling of long range 3He diffusion in the lung using a “slice-washout” method
چکیده انگلیسی
In healthy lung tissue, pulsed-gradient-spin-echo (PGSE) methods reveal apparent diffusion coefficients (ADC) of the order 0.20 cm2 s−1; for diffusion times of ≈2 ms. For these short diffusion times the ADC is only sensitive to structures approximately (2Dt)1/2 ≈ 0.6 mm in size. Recent work, using magnetic tagging of the longitudinal magnetization has revealed much smaller ADC values for longer length scales. In this work, the in vivo ADC from within the air-spaces, was measured using a new technique. The signal from a series of images was analyzed from a slice that was repeatedly imaged. Diffusion tends to “top-up” the non-renewable polarization within the slice, which leads to a non-exponential decay in image signal. Image data were compared to 1D finite-difference simulations of diffusion to calculate a long range ADC value. The results yield values of the order 0.034 cm2 s−1, which are nearly an order of magnitude smaller than those reported by PGSE measurements at shorter diffusion times.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetic Resonance - Volume 174, Issue 1, May 2005, Pages 28-33
نویسندگان
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