van Dorth Daniëlle, Venugopal Krishnapriya, van der Werff Karen N, Smits Marion, Warnert Esther A H, Hernandez-Tamames Juan A, van Osch Matthias J P, Poot Dirk H J
C. J. Gorter MRI Center, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands.
Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, Netherlands.
Magn Reson Med. 2025 Apr;93(4):1761-1770. doi: 10.1002/mrm.30383. Epub 2024 Nov 28.
Dynamic susceptibility contrast (DSC) MRI is commonly part of the clinical brain tumor imaging protocol. Usually, a preload of contrast agent is administered to minimize contrast-leakage T effects. However, recent studies have indicated that with adaptation of scan parameters (in particular, low flip angle), a preload is not required. For advanced approaches, like MR vascular fingerprinting (MRVF), which is based on combining gradient-echo and spin-echo readouts, excitation flip angles cannot easily be reduced, but postprocessing might alleviate leakage effects. In this study, the aim was to verify whether DSC-MRVF can be performed without preload.
A previously established simulation model was used to create a dictionary of DSC-MRVF signals resulting from a double-bolus injection with varying input values for permeability, vessel radius, and relative cerebral blood volume (rCBV). A sensitivity analysis based on a Cramer Rao Lower Bound approach was performed, from which the logarithmic ratio of standard deviations for parameter estimation was derived. A ratio above zero corresponded with a better determination without preload. Two brain tumor patients were included for validation.
The results show that the standard deviation for determining permeability was lower without preload, whereas for determining rCBV, the opposite result was found. For vessel radius, the standard deviation was similar with and without preload. The in vivo data reasonably agreed with the simulation results.
This work has shown the potential of DSC-MRVF with a single bolus injection for determining vessel radius and permeability, although for rCBV, a preload is still advisable.
动态磁敏感对比（DSC）磁共振成像（MRI）通常是临床脑肿瘤成像方案的一部分。通常会预先注射造影剂以尽量减少造影剂渗漏的T效应。然而，最近的研究表明，通过调整扫描参数（特别是低翻转角），无需预先注射。对于基于梯度回波和自旋回波读数相结合的先进方法，如磁共振血管指纹识别（MRVF），激发翻转角不易降低，但后处理可能会减轻渗漏效应。在本研究中，目的是验证DSC-MRVF是否可以在不预先注射的情况下进行。
使用先前建立的模拟模型创建一个DSC-MRVF信号字典，该字典由双团注注射产生，具有不同的渗透率、血管半径和相对脑血容量（rCBV）输入值。基于克拉美罗下界方法进行了敏感性分析，从中得出参数估计标准差的对数比。大于零的比值对应于不预先注射时更好的测定。纳入两名脑肿瘤患者进行验证。
结果表明，不预先注射时确定渗透率的标准差较低，而确定rCBV时则得到相反的结果。对于血管半径，有无预先注射时的标准差相似。体内数据与模拟结果合理一致。
这项工作表明了单次团注注射的DSC-MRVF在确定血管半径和渗透率方面的潜力，尽管对于rCBV，仍然建议预先注射。
