Department of Radiology, UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
J Magn Reson Imaging. 2010 Mar;31(3):556-61. doi: 10.1002/jmri.22077.
To prospectively evaluate whether dose reduction and the application of a prebolus technique can effectively alleviate signal saturation effects in T1 dynamic contrast enhanced (T1-DCE) magnetic resonance imaging (MRI) data in breast tumors and lead to increased diagnostic efficacy of the regional tumor blood flow (TBF) values obtained with deconvolution of T1-DCE MRI data.
After obtaining informed consent, 23 women (32-80 years) with histologically proven breast tumors underwent MR mammography that included a whole-breast T1 DCE sequence. In the slice where the tumor enhanced maximally, a prebolus protocol was applied. One mL of Gd-DTPA solution at 2 mL/s was injected at the beginning of a dynamic axial single slice inversion-prepared turbo field echo acquisition. At the 400th dynamic, a high dose of either 20 mL (15 patients) or 10 mL (8 patients) of contrast agent was injected at 2 mL/s and a further 400 dynamics were acquired. From the aortic prebolus curve an arterial input function (AIF) was reconstructed by time-shifting and adding the prebolus data. The relative enhancement time course from the tumor region of interest was deconvolved with the reconstructed AIF to generate the impulse response function, the maximum of which yielded the TBF. The institutional ethical committee approved the study.
Reducing the contrast dose by a factor of 2 led to an increase in diagnostic contrast for the TBF values of malignant and benign tumors by a factor of slightly more than 2. Addition of the prebolus technique improved this further by 45%. receiver operating characteristic analysis showed a significant increase of diagnostic yield related to the combined use of a prebolus and minimal dose.
Using a prebolus approach provides an estimate of the unsaturated AIF, while reduction of the high-dose bolus minimizes possible saturation effects in the tumor time course.
前瞻性评估在乳腺肿瘤的 T1 动态对比增强（T1-DCE）磁共振成像（MRI）数据中，减少剂量和应用预脉冲技术是否能有效减轻信号饱和效应，并提高 T1-DCE MRI 数据去卷积获得的局部肿瘤血流（TBF）值的诊断效能。
在获得知情同意后，23 名经组织学证实患有乳腺肿瘤的女性（32-80 岁）接受了包括全乳 T1 DCE 序列的磁共振乳腺成像检查。在肿瘤增强最大的层面，应用预脉冲方案。在动态轴向单层面反转准备涡轮场回波采集开始时，以 2 mL/s 的速度注入 1 mL 的 Gd-DTPA 溶液。在第 400 次动态时，以 2 mL/s 的速度快速注入 20 mL（15 例）或 10 mL（8 例）的对比剂，再采集 400 次动态。从主动脉预脉冲曲线通过时间移位和添加预脉冲数据重建动脉输入函数（AIF）。通过将重建的 AIF 与肿瘤感兴趣区的相对增强时间曲线进行卷积，生成脉冲响应函数，其最大值即为 TBF。该研究得到了机构伦理委员会的批准。
将对比剂剂量减少到原来的二分之一，使恶性和良性肿瘤的 TBF 值的诊断对比度增加了略多于两倍。添加预脉冲技术进一步提高了 45%。受试者工作特征分析显示，联合使用预脉冲和最小剂量可显著提高诊断效能。
使用预脉冲方法可以估计不饱和的 AIF，而减少高剂量的团注可以最大限度地减少肿瘤时间过程中的可能饱和效应。
