Improved Leakage Correction for Single-Echo Dynamic Susceptibility Contrast Perfusion MRI Estimates of Relative Cerebral Blood Volume in High-Grade Gliomas by Accounting for Bidirectional Contrast Agent Exchange
Improved Leakage Correction for Single-Echo Dynamic Susceptibility Contrast Perfusion MRI Estimates of Relative Cerebral Blood Volume in High-Grade Gliomas by Accounting for Bidirectional Contrast Agent Exchange
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DOI：
10.3174/ajnr.a4759
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发表时间：
2016-08-01
影响因子：
3.5
通讯作者：
Ellingson, B. M.
中科院分区：
文献类型：
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作者：
Leu, K.;Boxerman, J. L.;Ellingson, B. M.
作者的假设是，将双向造影剂转运纳入DSC MR成像信号模型将改善脑肿瘤的rCBV估计。对比造影剂单向外渗模型（Boxerman-Weisskoff）和双向造影剂交换模型。对于这两种模型，他们比较了21例胶质母细胞瘤患者与亲本泄漏污染弛豫率曲线的拟合优度以及模型间质弛豫率曲线与动态对比增强MR成像的差异。作者得出结论，双向模型通过将间质冲洗率纳入DSC MR成像松弛率模型，更准确地校正了高级别胶质瘤中由于血脑屏障破坏引起的造影剂外渗引起的T1或T2*增强。背景与目的：造影剂通过血脑屏障外渗会导致DSC MR成像对相对CBV的不准确估计。我们探讨了在单回波、梯度回波DSC MR成像的泄漏校正模型中加入间隙冲洗率是否能改善高级别胶质瘤的相对CBV估计。材料和方法：我们修改了传统的基于模型的后处理泄漏校正算法，假设造影剂单向外渗（Boxerman-Weisskoff模型），以考虑造影剂在血管内和血管外空间之间的双向交换（双向模型）。对于21例多形性胶质母细胞瘤患者，我们使用Akaike信息准则比较了模型与亲本泄漏污染松弛率曲线的拟合优度，并使用欧氏距离比较了模型间质松弛率曲线与动态对比增强MR成像的差异。结果：与双向模型相比，双向模型在所有21例多形性胶质母细胞瘤的>50%的增强肿瘤体素上改善了Akaike信息标准（77% 9%,P < 0.0001），在17/21例多形性胶质母细胞瘤的>50%的增强肿瘤体素上减少了欧氏距离（62% +/- 17%,P = 0.0041）。双向模型和动态对比度增强衍生的k（ep）显示出很强的相关性（r = 0.74 +/- 0.13）。平均而言，Boxerman-Weisskoff模型的肿瘤相对CBV增强比双向模型高16.6% +/- 14.0%。结论：将双向交换纳入单回声DSC MR成像的泄漏校正模型，可以改善模型与泄漏污染的DSC MR成像数据的拟合，并显著提高对高级别胶质瘤相对CBV的估计。
The authors' hypothesis is that incorporating bidirectional contrast agent transport into the DSC MR imaging signal model will improve rCBV estimates in brain tumors. A unidirectional contrast agent extravasation model (Boxerman-Weisskoff) was compared with a bidirectional contrast agent exchange model. For both models, they compared the goodness of fit with the parent leakage-contaminated relaxation rate curves and the difference between modeled interstitial relaxation rate curves and dynamic contrast-enhanced MR imaging in 21 patients with glioblastoma. The authors conclude that the bidirectional model more accurately corrects for the T1 or T2* enhancement arising from contrast agent extravasation due to blood-brain barrier disruption in high-grade gliomas by incorporating interstitial washout rates into the DSC MR imaging relaxation rate model.BACKGROUND AND PURPOSE: Contrast agent extravasation through a disrupted blood-brain barrier potentiates inaccurate DSC MR imaging estimation of relative CBV. We explored whether incorporation of an interstitial washout rate in a leakage-correction model for single-echo, gradient-echo DSC MR imaging improves relative CBV estimates in high-grade gliomas.MATERIALS AND METHODS: We modified the traditional model-based postprocessing leakage-correction algorithm, assuming unidirectional contrast agent extravasation (Boxerman-Weisskoff model) to account for bidirectional contrast agent exchange between intra- and extravascular spaces (bidirectional model). For both models, we compared the goodness of fit with the parent leakage-contaminated relaxation rate curves by using the Akaike Information Criterion and the difference between modeled interstitial relaxation rate curves and dynamic contrast-enhanced MR imaging by using Euclidean distance in 21 patients with glioblastoma multiforme.RESULTS: The bidirectional model had improved Akaike Information Criterion versus the bidirectional model in >50% of enhancing tumor voxels in all 21 glioblastoma multiformes (77% 9%; P < .0001) and had reduced the Euclidean distance in >50% of enhancing tumor voxels for 17/21 glioblastoma multiformes (62% +/- 17%; P = .0041). The bidirectional model and dynamic contrast-enhanced-derived k(ep) demonstrated a strong correlation (r = 0.74 +/- 0.13). On average, enhancing tumor relative CBV for the Boxerman-Weisskoff model exceeded that for the bidirectional model by 16.6% +/- 14.0%.CONCLUSIONS: Inclusion of the bidirectional exchange in leakage-correction models for single-echo DSC MR imaging improves the model fit to leakage-contaminated DSC MR imaging data and significantly improves the estimation of relative CBV in high-grade gliomas.