Quantitative contrast-enhanced MRI with superparamagnetic nanoparticles using ultrashort time-to-echo pulse sequences.
Quantitative contrast-enhanced MRI with superparamagnetic nanoparticles using ultrashort time-to-echo pulse sequences.
复制标题
DOI：
10.1002/mrm.25426
复制
发表时间：
2015-08
影响因子：
3.3
通讯作者：
Sridhar S
中科院分区：
文献类型：
--
作者：
Gharagouzloo CA;McMahon PN;Sridhar S
使用造影剂的常规MRI是半定量的，因为其固有地对体外磁化率伪影、场不均匀性、部分体积化、血管周围效应和运动/流动伪影敏感。在本文中，我们展示了一种使用超短回波时间脉冲序列的定量对比增强MRI技术，用于测量临床相关浓度的铁氧醇，铁氧醇是一种超顺磁性氧化铁纳米颗粒造影剂，在体外和体内具有高灵敏度和精确度。该方法通过在超短回波时间（UTE）下使用快速信号采集来产生具有纯T1加权和很少T2* 衰减的阳性对比度图像，从而实现了稳健、可重现的结果。被破坏的梯度回波方程被用来转换的UTE强度直接到浓度，使用实验确定的弛豫常数和图像采集参数。采集参数的多参数优化揭示了能够产生高保真度测量的最佳区域。在小鼠中纵向测量ferumoxytol的临床相关血管内浓度，具有高灵敏度和精密度（~7.1%误差）。通过连续抽血的元素铁分析独立验证MRI测量。ferumoxytol浓度的自动分割产生了高质量的三维图像灌注可视化。这种纵向量化血池CA浓度的能力是定量UTE对比增强（QUTE-CE）MRI所独有的，并使QUTE-CE MRI与核成像竞争。
Conventional MRI using contrast agents is semi-quantitative because it is inherently sensitive to extravoxular susceptibility artifacts, field inhomogeneity, partial voluming, perivascular effects, and motion/flow artifacts. Herein we demonstrate a quantitative contrast-enhanced MRI technique using ultrashort time-to-echo pulse sequences for measuring clinically relevant concentrations of ferumoxytol, a superparamagnetic iron oxide nanoparticle contrast agent with high sensitivity and precision in vitro and in vivo. The method achieves robust, reproducible results by using rapid signal acquisition at ultrashort time-to-echo (UTE) to produce positive contrast images with pure T1 weighting and little T2* decay. The spoiled gradient echo equation is used to transform UTE intensities directly into concentration using experimentally determined relaxivity constants and image acquisition parameters. A multiparametric optimization of acquisition parameters revealed an optimal zone capable of producing high-fidelity measurements. Clinically relevant intravascular concentrations of ferumoxytol were measured longitudinally in mice with high sensitivity and precision (~7.1% error). MRI measurements were independently validated by elemental iron analysis of sequential blood draws. Automated segmentation of ferumoxytol concentration yielded high quality three-dimensional images for visualization of perfusion. This ability to longitudinally quantify blood pool CA concentration is unique to quantitative UTE contrast-enhanced (QUTE-CE) MRI and makes QUTE-CE MRI competitive with nuclear imaging.
登录
查看更多内容
DOI：
10.1016/j.jacr.2007.03.002
发表时间：
2007-05-01
期刊：
Journal of the American College of Radiology : JACR
影响因子：
--
作者：
Amis, E Stephen Jr;Butler, Priscilla F;Zeman, Robert K
通讯作者：
Zeman, Robert K
影响因子：
82.9
作者：
Judenhofer, Martin S.;Wehrl, Hans F.;Pichler, Bernd J.
通讯作者：
Pichler, Bernd J.
影响因子：
3.3
作者：
Langley, Jason;Liu, Wei;Zhao, Qun
通讯作者：
Zhao, Qun
影响因子：
2.9
作者：
Farrar, Christian T.;Dai, Guangping;Sosnovik, David E.
通讯作者：
Sosnovik, David E.
影响因子：
3.5
作者：
Schabel, Matthias C.;Parker, Dennis L.
通讯作者：
Parker, Dennis L.