Intracranial plaque enhancement (IPE) identified by contrast-enhanced vessel wall MR imaging (VW-MR imaging) is an emerging marker of plaque instability related to stroke risk, but there was no standardized timing for postcontrast acquisition. We aim to explore the optimal postcontrast timing by using multiphase contrast-enhanced VW-MR imaging and to test its performance in differentiating culprit and nonculprit lesions.

Patients with acute ischemic stroke due to intracranial plaque were prospectively recruited to undergo VW-MR imaging with 1 precontrast phase and 4 consecutive postcontrast phases (9 minutes and 13 seconds for each phase). The signal intensity (SI) values of the CSF and intracranial plaque were measured on 1 precontrast and 4 postcontrast phases to determine the intracranial plaque enhancement index (PEI). The dynamic changes of the PEI were compared between culprit and nonculprit plaques on the postcontrast acquisitions.

Thirty patients with acute stroke (aged 59 ± 10 years, 18 [60%] men) with 113 intracranial plaques were included. The average PEI of all intracranial plaques significantly increased (up to 14%) over the 4 phases. There was significantly increased PEI over the 4 phases for culprit plaques (an average increase of 23%), but this was not observed for nonculprit plaques. For differentiating culprit and nonculprit plaques, we observed that the performance of IPE in the second postcontrast phase (cutoff = 0.83, AUC = 0.829 [0.746–0.893]) exhibited superior accuracy when compared with PEI in the first postcontrast phase (cutoff = 0.48; AUC = 0.768 [0.680–0.843]) (P = .022).

A 9-minute delay of postcontrast acquisition can maximize plaque enhancement and better differentiate between culprit and nonculprit plaques. In addition, culprit and nonculprit plaques have different enhancement temporal patterns, which should be evaluated in future studies.

通过对比增强血管壁 MR 成像（VW-MR 成像）识别的颅内斑块增强 (IPE) 是与中风风险相关的斑块不稳定的新兴标志物，但没有标准化的对比后采集时间。我们的目标是通过使用多相对比增强 VW-MR 成像来探索最佳的对比后时机，并测试其在区分罪魁祸首和非罪魁祸首病变方面的性能。

前瞻性招募因颅内斑块导致的急性缺血性中风患者接受 VW-MR 成像，包括 1 个造影前阶段和 4 个连续的造影后阶段（每个阶段 9 分 13 秒）。在 1 个造影前和 4 个造影后阶段测量 CSF 和颅内斑块的信号强度 (SI) 值，以确定颅内斑块增强指数 (PEI)。在对比后采集中，比较了罪魁祸首和非罪魁祸首斑块之间 PEI 的动态变化。

包括 30 名急性中风患者（年龄 59 ± 10 岁，18 名 [60%] 男性），有 113 个颅内斑块。所有颅内斑块的平均 PEI 在 4 个阶段显着增加（高达 14%）。罪魁祸首斑块的 PEI 在 4 个阶段中显着增加（平均增加 23%），但在非罪魁祸首斑块中未观察到这种情况。对于区分罪魁祸首和非罪魁祸首斑块，我们观察到，与第一对比后阶段的 PEI（截止值 = 0.48；截止值 = 0.48； AUC = 0.768 [0.680–0.843]) ( P = .022)。

造影后采集延迟 9 分钟可以最大限度地增强斑块，并更好地区分罪魁祸首和非罪魁祸首斑块。此外，罪魁祸首和非罪魁祸首斑块具有不同的增强时间模式，应在未来的研究中进行评估。