Zhou Wei, Dinishak David, Lane Barton, Hernandez-Boussard Tina, Bech Fritz, Rosen Allyson
Department of Surgery, Stanford University, Stanford, Calif; VA Palo Alto Health Care System, Palo Alto, Calif, USA.
J Vasc Surg. 2009 Dec;50(6):1314-9. doi: 10.1016/j.jvs.2009.07.105. Epub 2009 Oct 17.
Subclinical microemboli on diffusion-weighted magnetic resonance imaging (DWI) have been identified immediately following carotid revascularization procedures, but the clinical significance and long-term effects are largely unknown. The purpose of this study was to evaluate long-term radiographic outcomes of these DWI lesions.
Patients who underwent perioperative magnetic resonance imaging (MRI) evaluations for carotid interventions at a single institution from July 2004 to December 2008 were evaluated, particularly those who had additional follow-up MRI. DWI with apparent diffusion coefficient (ADC), fluid-attenuated inversion recovery (FLAIR), and T2-weighted MRI images were compared to determine long-term effect of microemboli.
One-hundred sixty-eight consecutive patients (68 carotid artery stenting [CAS] and 100 carotid endarterectomy [CEA]) who received perioperative MRI were included. All CAS were performed with an embolic protection device. The incidence of microemboli was significantly higher in the CAS group than the CEA group (46.3% and 12%, respectively, P < .05) despite a relative low incidence of procedure-associated neurologic symptoms in both groups (2.9% vs 2%). Thirty patients (16 CAS and 14 CEA) who had follow-up MRI were further analyzed and a total of 50 postoperative DWI lesions (mean size 46.57 mm(2); range 16 to 128 mm(2)) were identified among them. During a mean MRI follow-up of 10 months (range, 2 to 23 months), residual MRI abnormalities were only identified in DWI lesions larger than 60 mm(2) on postoperative MRI and on postoperative FLAIR images (n = 5, P < .001). The CEA group had fewer but larger ipsilateral distributed emboli (total 12 lesions, mean 79 mm(2)) compared with the CAS group (total 38 lesions, mean 27.5 mm(2), P < .05).
The majority of microemboli do not have long-term radiographic sequelae. Size and hyperintensity on postoperative FLAIR are predictive of residual brain structure abnormality, and further neurocognitive evaluations are warranted.
在颈动脉血运重建术后立即通过弥散加权磁共振成像（DWI）检测到亚临床微栓子，但临床意义和长期影响在很大程度上尚不清楚。本研究的目的是评估这些DWI病变的长期影像学结果。
对2004年7月至2008年12月在单一机构接受颈动脉介入围手术期磁共振成像（MRI）评估的患者进行评估，特别是那些接受额外随访MRI的患者。比较具有表观扩散系数（ADC）的DWI、液体衰减反转恢复（FLAIR）和T2加权MRI图像，以确定微栓子的长期影响。
纳入168例连续接受围手术期MRI的患者（68例行颈动脉支架置入术[CAS]，100例行颈动脉内膜切除术[CEA]）。所有CAS均使用栓子保护装置进行。尽管两组与手术相关的神经症状发生率相对较低（分别为2.9%和2%），但CAS组微栓子的发生率显著高于CEA组（分别为46.3%和12%，P < 0.05）。对30例接受随访MRI的患者（16例CAS和14例CEA）进行进一步分析，共在其中发现50个术后DWI病变（平均大小46.57 mm²；范围16至128 mm²）。在平均10个月（范围2至23个月）的MRI随访期间，仅在术后MRI和术后FLAIR图像上大于60 mm²的DWI病变中发现残留的MRI异常（n = 5，P < 0.001）。与CAS组（共38个病变，平均27.5 mm²）相比，CEA组同侧分布的栓子数量较少但较大（共12个病变，平均79 mm²，P < 0.05）。
大多数微栓子没有长期影像学后遗症。术后FLAIR上的大小和高信号强度可预测残留脑结构异常，因此有必要进行进一步的神经认知评估。
