کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5407136 | 1393204 | 2008 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The effect of impermeable boundaries of arbitrary geometry on the apparent diffusion coefficient
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: The effect of impermeable boundaries of arbitrary geometry on the apparent diffusion coefficient The effect of impermeable boundaries of arbitrary geometry on the apparent diffusion coefficient](/preview/png/5407136.png)
چکیده انگلیسی
The apparent diffusion coefficient (ADC) obtained from NMR measurements is modelled for diffusion in a compartment restricted by an impermeable boundary. For a given pulse sequence, the ADC can be determined from the connected velocity autocorrelation function (the second-order velocity cumulant), which we show can be expressed as a double surface integral over the boundary, involving the probability for molecules to diffuse from one boundary point to another. There is no restriction on the geometry of the boundary. This result allows a fast calculation of the ADC for an arbitrary time course of the diffusion-sensitizing gradient. Explicit examples are given for diffusion within three basic geometries for different pulse sequences. The ADCs measured with the Stejskal-Tanner pulse sequence and a more realistic pulse sequence with slice selection gradient and eddy current compensation are found to yield almost identical results. The application of the results are discussed in relation to determination of the microscopic structure of brain white matter.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetic Resonance - Volume 194, Issue 1, September 2008, Pages 128-135
Journal: Journal of Magnetic Resonance - Volume 194, Issue 1, September 2008, Pages 128-135
نویسندگان
Astrid F. Frøhlich, Sune N. Jespersen, Leif Ãstergaard, Valerij G. Kiselev,