血管壁磁共振成像在老年颈动脉粥样硬化患者术前评估中的应用

The value of carotid plaque magnetic resonance imaging and sequence optimization in preoperative assessment in elderly patients with carotid atherosclerosis

目的探讨磁共振成像（MRI）对老年颈动脉粥样硬化患者术前评估的应用价值及序列优化。方法70例老年缺血性脑血管疾病的患者，超声检查发现颈动脉分叉处有斑块，分别进行颈动脉MRI和数字减影血管造影（DSA）检查。颈动脉MRI检查序列包括平扫及增强T1加权（T1W1）、T2加权、质子加权（PDWI）和3D时间飞跃法MR血管成像（3INTOFMRA）。扫描完成后将图像分为两种序列组合，即5序列组合（上述5个序列）和2序列组合（T1WI和3DTOF）MRI图像。DSA检查摄取颅外段颈动脉常规正位及侧位图像。分析MRI与DSA之间、MRI不同序列组合之间对管腔狭窄和纤维帽破溃的检出差异。结果70例患者中1例图像质量较差，余69例中除3支血管为支架置入术后，共135支血管。5序列及2序列MRI组合检测的平均管腔狭窄程度分别为（38．3±31．0）％和（38．5±30．9）％，差异无统计学意义（t=2．447，P〉0．05）。DSA检测的平均血管狭窄程度为（35．1±31．8）％，以其作为金标准，MRI两种序列组合与金标准间具有很好的一致性（Kappa值0．773）。两种序列组合分别检出36支血管具有溃疡斑块，差异无统计学意义；DSA检出16支血管具有溃疡斑块，MRI与DSA检出溃疡斑块的差异有统计学意义（x2=12．0，P〈0．01）。结论MRI可以准确判断颈动脉的管腔狭窄程度并检出溃疡斑块的存在，通过对扫描序列的优化可以有效减少检查时间，是老年颈动脉粥样硬化患者术前评估的较好的检查手段。

Objective To study the value of carotid plaque magnetic resonance imaging （MRI） in pre-operation assessment in the elderly patients with carotid atherosclerosis and explore the possibility of minimizing the contrast weightings to gain sweeptime. Methods Totally 70 elderly patients with cerebral ischemia （average age of 68.8 years） underwent carotid MRI and digital subtraction angiography （DSA） due to the appearance of carotid plaque detected by ultrasound. Carotid plaque MRI was acquired with 3.0T MR scanner and 8 channel surface coil. The standard carotid plague MRI program included pre-and post-contrast T1 weighted imaging （TlWI）, T2 weighted imaging, proton density weighted imaging and 3D time of flight MR angiography （3D TOF MRA）. All these program were divided into two combinations： the 5 sequence MRI （all the sequences） and 2-sequence MRI （TIWI and TOF MRA）. Digital subtraction angiography （DSA） in coronal and lateral views of carotid artery was performed with GE Advantx LCN＋ . The software SPSS 13.0 was used to statistically analyze the difference between MRI and DSA, and that of two sequence combinations was used in the detection of luminal stenosis and fibrous cap （FC） rupture. Results Totally 135 arteries were analyzed while 3 arteries in one patient were excluded due to the poor quality image and stent placement. The degree of luminal stenosis were （38.3±31.0）% and （38.5± 30.9）%, respectively, detected by the two MRI sequence-combination with no significant difference （t=2. 447, P〉0.05） and was （35.1±81.8）% by DSA. There was a good concordance between MRI and DSA in luminal stenosis detection （Kappa value： 0. 773）. No statistical difference was found between two MR sequence combinations in detecting FC rupture （both in 36 vessels）. DSA detected FC rupture of 16 vessels, showing remarkably difference contrast to MRI（z2 = 12.0, P〈0.01）. Conclusions MRI can accurately detect the luminal stenosis and FC rupture. The short time scanning resulting from sequence optimization could make MRI much more suitable than DSA to do the pre-operation assessment for senile carotid atherosclerotic patients.