Tumor Blood Volume Determination by Using Susceptibility-corrected ΔR2☆ Multiecho MR
Tumor Blood Volume Determination by Using Susceptibility-corrected ΔR2☆ Multiecho MR
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DOI：
10.1148/radiol.10090832
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发表时间：
2010-06-01
期刊：
影响因子：
19.7
通讯作者：
Bremer, Christoph
中科院分区：
文献类型：
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作者：
Persigehl, Thorsten;Wall, Alexander;Bremer, Christoph
目的：评估磁敏校正多回波磁共振 (MR) 弛豫测量技术，以准确、稳健地确定 Delta R2（星）作为灌注肿瘤血量的无创替代参数。 材料和方法：所有实验均得到机构动物护理委员会的批准。在具有不同超顺磁氧化铁（SPIO）颗粒浓度的玻璃管模型中以及在具有DU-4475、HT-1080和MDA-MB-435肿瘤的肿瘤小鼠异种移植物中（总共n = 15个，每个模型n = 5个）注射不同超小SPIO（USPIO）剂量后具有不同程度的新生血管，通过使用固定回波时间确定横向弛豫率的变化（Delta R2（星号）） (TE) 22 毫秒和磁化率校正多梯度回波技术。确定每个肿瘤的平均 Delta R2（星号）值和血管体积分数（VVF），并与独立的体内荧光肿瘤灌注测量进行比较，组织学分析有助于确定微血管密度（MVD）。通过使用方差分析和线性相关性来测试统计差异。结果：对于体模研究，使用 22 毫秒的固定 TE 计算的 Delta R2（星形）图显示出与磁敏度校正多回波技术相比更高的噪声指数标准偏差。对于异种移植模型，平均肿瘤 Delta R2（星号）值（平均值的+/-标准误差）显示各种肿瘤之间存在显着差异（例如，DU-4475：12.3 秒(-1) +/- 2.67、HT-1080：36.47 秒(-1) +/- 5.84 和MDA-MB-435：64.01 秒(-1)每公斤 80 微摩尔铁时为 +/- 8.87；P< .05)。 Delta R2（星号）值以剂量依赖性和线性方式增加，从而实现可重复稳定的 VVF 测量。荧光肿瘤灌注测量和 MVD 计数证实了 MR 结果。结论：磁敏校正多回波 MR 弛豫测量可以高度准确和稳健地确定 Delta R2（星形）和 VVF，并在临床相关剂量的 USPIO 下具有出色的肿瘤表征动态范围。
Purpose: To evaluate a susceptibility-corrected multiecho magnetic resonance (MR) relaxometry technique for an accurate and robust determination of Delta R2(star) as a noninvasive surrogate parameter of the perfused tumor blood volume.Materials and Methods: All experiments were approved by the institutional animal care committee. In a glass tube phantom with different superparamagnetic iron oxide (SPIO) particle concentrations and at tumor mice xenografts with DU-4475, HT-1080, and MDA-MB-435 tumors (n = 15 total, n = 5 per model) with different degrees of neovascularization after injection of different ultrasmall SPIO (USPIO) doses changes of the transverse relaxation rate (Delta R2(star)) were determined by using a fixed echo time (TE) of 22 msec and a susceptibility-corrected multigradient-echo technique. The mean Delta R2(star) value and the vascular volume fraction (VVF) of each tumor was determined and compared with independent in vivo fluorescent tumor perfusion measurements and histologic analysis helped determine microvessel density (MVD). Statistical differences were tested by using analysis of variance and linear correlations.Results: For the phantom study, Delta R2(star) maps calculated with a fixed TE of 22 msec showed a higher standard deviation of the noise index compared with the susceptibility-corrected multiecho technique. For the xenograft model, mean tumor Delta R2(star) values (+/- standard error of the mean) showed signifi cant differences between the various tumors (eg, DU-4475: 12.3 sec(-1) +/- 2.67, HT-1080: 36.47 sec(-1) +/- 5.84, and MDA-MB-435: 64.01 sec(-1) +/- 8.87 at 80 mu mol of iron per kilogram; P< .05). Delta R2(star) values increased dose dependently and in a linear fashion, resulting in reproducibly stable VVF measurements. Fluorescent tumor perfusion measurements and MVD counts corroborated the MR results.Conclusion: Susceptibility-corrected multiecho MR relaxometry allows a highly accurate and robust determination of Delta R2(star) and VVF with an excellent dynamic range for tumor characterization at clinically relevant doses of USPIO.