3.0 T磁共振多序列成像在肛瘘诊断分型中的应用效果分析

Effect analysis of applying 3.0 T multi-sequence MRI in the diagnosis and classification of anal fistula

目的探究3.0 T磁共振多序列成像在肛瘘诊断和临床分型判断中的应用价值。方法回顾性分析56例肛瘘患者临床及影像学资料,所有患者均行3.0 T磁共振多序列成像检查,检查序列包括T1加权成像(T1WI)、T2加权成像(T2WI)、T2WI抑脂序列、扩散加权成像(DWI)序列和增强扫描,分析肛瘘不同扫描序列影像学特征,比较不同序列显示肛瘘内口及瘘管的准确性。以肛瘘位置及走行结合Praks分型和临床经验将肛瘘分为括约肌间型、经括约肌型、括约肌上型、括约肌外型及复杂型,并以截石位时钟法描述内口分布状况。结果瘘管于T1WI呈条状略低信号影,在T2WI序列、T2WI抑脂序列及DWI序列上呈条状或管状高信号,在T1WI增强图像上瘘管呈明显管状强化,内口多表现为圆点状强化。括约肌间型12例,经括约肌型14例,括约肌上型7例,括约肌外型6例,复杂型17例。56例患者病理学检测证实有43个内口和62个瘘管,内口位于截石位3~9点方向。T1WI序列显示36个内口(83.72%),53个瘘管(85.48%);T2WI序列显示37个内口(86.05%),55个瘘管(88.71%);T2WI抑脂序列显示41个内口(95.35%),59个瘘管(95.16%);DWI序列显示42个内口(97.67%),60个瘘管(96.77%);增强扫描序列显示42个内口(97.67%),61个瘘管(98.39%)。DWI对内口及瘘管的检测准确率与T2WI抑脂序列对比,差异无统计学意义(P>0.05)。增强扫描序列对内口和瘘管的检测准确率与T2WI抑脂序列及DWI对比,差异无统计学意义(P>0.05)。增强扫描序列对内口和瘘管的检测准确率高于T1WI序列、T2WI序列,差异有统计学意义(P<0.05)。结论3.0 T磁共振多序列成像在肛瘘诊断与分型中显象效果突出,能清晰表现内口与瘘管位置,对复杂性肛瘘检查意义突出,对肛瘘外科手术有指导作用。

Objective To investigate the application value of 3.0 T multi-sequence magnetic resonance imaging(MRI)in the diagnosis and clinical classification of anal fistula.Methods The clinical and imaging data of 56 patients with anal fistula was retrospectively analyzed.All patients were subjected to 3.0 T MRI examination.The examination sequence comprised T1 weighted imaging(T1WI),T2 weighted imaging(T2WI),T2WI lipid suppression sequence,diffusion weighted imaging(DWI)sequence and enhanced scan.The imaging characteristics of different scanning sequences of anal fistula were analyzed.The accuracy of different sequences in displaying internal opening and fistula of the anal fistula was compared.Anal fistulas were divided into intersphincteric type,transsphincteric type,suprasphincteric type,external sphincter type and complex type based on the position and course of anal fistula combined with Praks classification and clinical experience.Results The fistula showed a stripe-like shadow low signal on T1WI,and a strip-like or tubular shape high signal on T2WI sequence,T2WI lipid suppression sequence and DWI sequence.On T1WI enhanced image,the fistula showed an improved signal of clear tubular shape with most of the inner mouth representing as enhanced round points.12 cases were of intersphincteric type,14 cases were of transsphincteric type,7 cases were of suprasphincteric type,6 cases were of external sphincter type,and 17 cases were of complex type.Pathological examination of 56 patients confirmed that there were 43 internal orifices and 62 fistulas,wherein the internal orifices located in the 3-9 o’clock direction of the lithotomy.T1WI sequence showed 36 internal openings(83.72%)and 53 fistulas(85.48%);T2WI sequence showed 37 internal openings(86.05%)and 55 fistulas(88.71%);T2WI lipid suppression sequence showed 41 internal openings(95.35%)and 59 fistulas(95.16%);DWI sequence showed 42 internal openings(97.67%)and 60 fistulas(96.77%);and the enhanced scan sequence showed 42 internal openings(97.67%)and 61 fistulas(98.39%).The difference in the detection accuracy of internal orifice and fistula between DWI and T2WI lipid suppression sequence was not statistically significant(P>0.05).The difference in the detection accuracy of internal orifice and fistula by comparing the enhanced scanning sequence with T2WI lipid suppression sequence and DWI was not statistically significant(P>0.05).The enhanced scanning sequence had higher detection accuracy of internal orifice and fistula than T1WI and T2WI sequences,and the difference was statistically significant(P<0.05).Conclusion 3.0 T multi-sequence MRI has outstanding imaging results in the diagnosis and classification of anal fistula.It can clearly show the position of internal orifice and fistula.It has outstanding significance in the examination of complex anal fistula,so it plays a guiding role in the surgical operation of anal fistula.