磁共振成像在复杂性肛瘘诊断中的应用

目的探讨磁共振成像（MRI）在复杂性肛瘘诊断中的应用价值。方法28例临床诊断为复杂性肛瘘的患者，术前进行磁共振相控阵列线圈检查。以手术结果为标准，比较术前指诊和MRI的诊断结果。结果有25例患者诊断为复杂性肛瘘，1例为骶前囊肿合并与直肠相通的瘘道，2例肛瘘伴癌变。25例肛瘘Parks分类显示：经括约肌肛瘘3例，括约肌间肛瘘10例，括约肌外肛瘘5例，括约肌上肛瘘7例；MRI与术前指诊检查结果比较，内口检出符合率为84％比48％；原发主管、支管或脓腔检出准确率为100％比76％、94．7％比57．9％；两种检查方法比较，差异有统计学意义（P〈0．01）。结论应用MRI相控阵列线圈能准确定位复杂性肛瘘的内口、瘘管的走向及其与肛管直肠括约肌复合体之间的复杂关系，对排除肛瘘伴其他肛管直肠周围病变具有确切意义。

Application of magnetic resonance imaging in the diagnosis of complex anal fistula

OBJECTIVE: To evaluate the value of magnetic resonance imaging (MRI) in the diagnosis of complex anal fistula. METHODS: The preoperative digital examination and MRI with the phased-array coil were implemented for 28 patients who were clinically suspected with complex anal fistula. The final diagnosis were based on surgical findings. Outcomes of MRI and digital examination were compared with surgical results. RESULTS: Twenty-five patients were diagnosed as complex anal fistula, 1 presacral cyst and 2 chronic anorectal fistula combined with perianal mucinous adenocarcinoma. All the patients were correctly diagnosed by MRI,while the patients with presacral cyst and perianal mucinous adenocarcinoma could not be diagnosed correctly by digital examination. According to the Parks classification, 3 patients were suffered from trans-sphincteric fistula, 10 intersphincteric, 5 supra- sphincteric and 7 extra-sphincteric. The diagnosis rates of the internal opening with digital examination and MRI were 48% and 84%, the rates of the primary tract were 76% and 100%, and the rates of the secondary extensions were 57.9% and 94.7% respectively. The differences in detection of internal opening, primary tract and secondary extensions between MRI and digital examination were significant (P<0.01). CONCLUSION: MRI with the phased-array coil can correctly orient the internal opening and direction of the complex anal fistula, and find the relationship between anorectal sphincters and the complex fistula.