Abstract: ［Abstract］ Objective To summarize the MRI features and reasons of misdiagnosis of intracranial extracerebral cavernous malformations （ECMs） for improving the diagnostic level. Methods The MRI manifestations of 9 patients diagnosed ECMs with surgically and pathologically were retrospectively analyzed. The lesion and signal characteristics were observed， and misdiagnosis was analyzed by combining pathological characteristics. Results MRI examination of 9 patients had multiple lesions in 2 cases， namely， internal auditory canal combined with intracerebral cavernous hemangioma， single lesion in 7 cases， with the location at cavernous sinus in 3 cases， at middle cranial fossa， posterior horn of lateral ventricle， the fourth ventricle and confluence of sinuses separately each had one. Peripheral tissue edema in 1 case and no edema in 8 cases. Non?uniform signal were found in 5 patients， uniform signal was found in 4 patients， presenting as iso?signal on T1WI， high?signal on T2WI and FLAIR， and heterogeneous enhancement， the intensity of which was similar to vascular enhancement. Presenting iso?signal on susceptibility weighted imaging（SWI） in 3 cases， and heterogeneous signal in 4 cases. Presenting mild high?signal on diffusion weighted image（DWI） in 3 case and heterogeneous iso?signal in 1 case， presenting slightly high?signal on appearance diffusion coefficient（ADC） in 4 cases. The choline（Cho） peak and N?Acetyl?L?aspartic（NAA） peak recorded at baseline level in 3 patients were scanned magnetic resonance spectrum（MRS）， one of which was found Lactate（Lac） peak. One patient presented low blood flow of brain in perfusion weighted imaging（PWI）. Conclusion ECMs are cerebral vascular malformations，which are characterized by high?signal on T2WI and FLAIR，finding “iron ring sign”， with low perfusion and rare peripheral tissue edema. Making use of new technology such as SWI， MRS， PWI， can increase the diagnostic accuracy of ECMs， as well as providing comprehensive and accurate information for clinical therapy.

Key words: susceptibility weighted imaging；magnetic resonance spectroscopy, misdiagnosis analysis, extracerebral cavernous malformations MRI features

摘要： ［摘要］ 目的 分析颅内脑外型海绵状血管瘤（ECMs）的MRI表现及误诊原因，以提高术前诊断准确率。方法 回顾性分析9例经手术病理确诊ECMs患者的MRI表现，观察病变部位、信号特点，结合病理特点，进行误诊分析。结果 本组9例病例中，多发病灶2例，即内听道并脑内型海绵状血管瘤，单发病灶7例，其中病变位于海绵窦区3例，颅中窝、侧脑室后角、第四脑室、窦汇区各1例。周围组织水肿1例，无水肿8例。信号不均匀者5例，均匀者4例，以T1WI呈等信号、T2WI与FLAIR呈高信号为主，增强后早期明显强化，强化程度同血管样强化。4例SWI呈等、低、高混杂信号，2例呈等信号。DWI呈稍低信号3例，1例呈等低混杂信号，ADC图呈稍高信号4例。MRS中Cho、NAA峰位于基线水平者3例，发现Lac1例。PWI提示低灌注1例。结论 ECMs以T2WI、FLAIR高信号为主、常见“环铁征”、低灌注的脑组织外血管畸形病变，少见周围组织水肿。利用SWI、MRS及PWI等影像新技术，提高ECMs的诊断准确性，为临床治疗提供全面、准确的信息。

关键词: 磁共振波谱成像, 磁共振表现, 误诊分析, 磁敏感加权成像, 脑外型海绵状血管瘤