Diffusion-weighted imaging of the prostate and rectal wall: comparison of biexponential and monoexponential modelled diffusion and associated perfusion coefficients
Diffusion-weighted imaging of the prostate and rectal wall: comparison of biexponential and monoexponential modelled diffusion and associated perfusion coefficients
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DOI：
10.1002/nbm.1328
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发表时间：
2009-04-01
影响因子：
2.9
通讯作者：
de Souza, N. M.
中科院分区：
文献类型：
--
作者：
Riches, S. F.;Hawtin, K.;de Souza, N. M.
这项研究比较了正常和恶性前列腺组织以及正常直肠壁组织的扩散加权成像的单指数和双指数模型的参数。对50例IC期前列腺癌患者行直肠T(2)加权和扩散加权成像，共11个扩散敏感值(b值分别为0、1、2、4、10、20、50、100、200、400、800 S/mm(2))。感兴趣区位于非恶性中央腺体及周围带、恶性前列腺组织和正常直肠壁组织。在不同的b值范围内，分别用单指数模型和双指数模型进行拟合，得到单指数模型的表观扩散系数(ADC)和双指数模型的扩散系数、灌流系数和灌流分数。在所有组织中，在整个b值范围内，单指数模型的ADC值显著高于双指数模型的相应扩散系数。随着最小b值的增加，ADC减小，在某些b值范围内，ADC等于扩散系数。当包含低b值时，双指数模型最好地描述了数据，这表明存在快速血流灌注成分。两种模型都不能根据扩散系数区分良性前列腺组织，但直肠壁组织和恶性前列腺组织的扩散系数明显低于正常前列腺组织。灌注系数和比例在人群中的变化很大，因此它们的临床应用可能有限，但当将临床差异归因于组织内的扩散时，从报告的扩散系数中去除这种可变的灌注成分是很重要的。版权所有(C)2008 John Wiley&Sons，Ltd.
This study compares parameters from monoexponential and biexponential modelling of diffusion-weighted imaging of normal and malignant prostate tissue and normal rectal wall tissues. Fifty men with Stage Ic prostate cancer were studied using enclorectal T(2)-weighted imaging and diffusion-weighted imaging with 11 diffusion-sensitive values (b-values = 0, 1, 2, 4, 10, 20, 50, 100, 200, 400, 800 s/mm(2)). Regions of interest were drawn within non-malignant central gland and peripheral zone, malignant prostate tissue and normal rectal wall tissue. Both a monoexponential and biexponential model was fitted over various b-value ranges, giving an apparent diffusion coefficient (ADC) from the monoexponential model and a diffusion coefficient, perfusion coefficient and perfusion fraction from the biexponential model. In all tissues, over the full range of b-values, the ADC from the monoexponential model was significantly higher than the corresponding diffusion coefficient from the biexponential model. As the minimum b-value increased, the ADC decreased and was equal to the diffusion coefficient for some b-value ranges. The biexponential model best described the data when low b-values were included, suggesting that there is a fast perfusion component. Neither model could distinguish between benign prostate tissues on the basis of diffusion coefficients, but the rectal wall tissue and malignant prostate tissue had significantly lower diffusion coefficients than normal prostate tissues. Perfusion coefficients and fractions were highly variable within the population, so their clinical utility may be limited, but removal of this variable perfusion component from reported diffusion coefficients is important when attributing clinical differences to diffusion within tissues. Copyright (C) 2008 John Wiley & Sons, Ltd.