Background

Measurement of luminal stenosis and determination of plaque instability using MR plaque imaging are effective strategies for evaluating high-risk carotid stenosis. Nevertheless, new methods are required to identify patients with carotid stenosis at risk of future stroke. We aimed to clarify the mechanisms and clinical implications of the hyperintense vessel sign (HVS) as a marker of high-risk carotid stenosis.

Methods

We included 148 patients who underwent carotid stent (CAS) or carotid endarterectomy (CEA). MRI FLAIR was performed to detect HVS prior to and within 7 days after CAS/CEA. MR plaque imaging and ¹²³I-iodoamphetamine SPECT was performed prior to CEA/CAS. Detailed characteristics of HVS were categorized in terms of symptomatic status, hemodynamic state, plaque composition, and HVS on time series.

Results

Forty-six of 80 symptomatic hemispheres (57.5%) and 5 of 68 asymptomatic hemispheres (7.4%) presented HVS (P < 0.01). Of the 46 symptomatic hemispheres with HVS, 19 (41.3%) presented with hemodynamic impairment and 27 (58.7%) presented without hemodynamic impairment. Of 19 hemispheres with hemodynamic impairment, 12 subjects (63.2%) showed high intensity and 7 (36.8%) showed iso-intensity plaques on T1WI. All 27 hemispheres without hemodynamic impairment showed high-intensity plaques. Of the five asymptomatic and HVS-positive hemispheres, one showed hemodynamic impairment; MR plaque imaging revealed T1 iso-intensity. The other four hemispheres that did not show hemodynamic impairment showed T1WI high-intensity plaques.

Conclusion

There are two possible mechanisms of HVS, hemodynamic impairment due to severe carotid stenosis and micro-embolism from unstable plaques. HVS could be a radiological marker for high-risk carotid stenosis.

中文翻译：

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高强度血管在体液倒置恢复成像上的体征：高危颈动脉狭窄的新型成像标志物-MRI和SPECT研究。

背景

测量腔狭窄和使用MR斑块成像确定斑块不稳定性是评估高风险颈动脉狭窄的有效策略。尽管如此，仍需要新的方法来识别具有未来卒中风险的颈动脉狭窄患者。我们旨在阐明高强度血管征（HVS）作为高危颈动脉狭窄标志物的机制和临床意义。

方法

我们纳入了148例接受了颈动脉支架（CAS）或颈动脉内膜切除术（CEA）的患者。在CAS / CEA之前和之后的7天内进行MRI FLAIR检测HVS。在CEA / CAS之前先进行MR斑块成像和¹²³ I-碘苯丙胺SPECT。HVS的详细特征按症状状态，血液动力学状态，菌斑组成和时间序列上的HVS进行分类。

结果

80个有症状半球中的46个（57.5％）和68个无症状半球中的5个（7.4％）表现为HVS（P <0.01）。在46例有HVS的症状性半球中，有19例（41.3％）表现为血液动力学损害，而27例（58.7％）表现为无血液动力学损害。在19个有血流动力学障碍的半球中，有12名受试者（63.2％）表现出高强度，而7名受试者（36.8％）表现出T1WI上的等强度斑块。没有血流动力学损害的所有27个半球均显示高强度斑块。在5个无症状和HVS阳性的半球中，有1个显示血流动力学障碍。MR斑块成像显示T1等强度。没有显示出血流动力学损害的其他四个半球显示出T1WI高强度斑块。

结论

HVS有两种可能的机制：严重的颈动脉狭窄引起的血流动力学损害和不稳定斑块引起的微栓塞。HVS可能是高危颈动脉狭窄的放射学标志物。