质子加权预饱和脂肪抑制序列在肛瘘中的应用价值

The Application Value of MRI PDW PFS Sequence in the Perianal Fistulas

目的评价质子加权预饱和脂肪抑制序列(PDW PFS)对肛瘘显示的准确性及图像质量的清晰性,探讨PDW PFS在肛瘘中的应用价值。资料与方法 20例经手术证实的肛瘘患者术前进行MRI检查,序列包括T1WI、T2W频谱选择性衰减反转恢复序列(SPAIR)和PDW PFS。MRI检查前均向患者肛管直肠内置入肛肠水囊以撑开肛管和直肠。获得图像后,观察患者的瘘管、内口和肛周脓肿,评估和比较MRI各序列显示的瘘管、内口、脓腔,并对PDW PFS和T2W SPAIR序列瘘管的信号强度(SI)、信噪比(SNR)及瘘管与周围肌肉的对比噪声比(CNR)进行测量及比较。结果 PDW PFS序列显示瘘管(100%)、内口(95.7%)、肛周脓肿(100%)的准确率较T1WI及T2WSPAIR序列为高。Kruskal Wallis检验显示上述各序列对瘘管(χ2=6.95,P<0.05)及内口(χ2=31.53,P<0.05)的显示具有显著统计学差异,PDW PFS序列显示瘘管及内口最多。PDW PFS序列SI、SNR值和CNR值均显著高于T2W SPAIR序列(P<0.05)。结论 PDW PFS成像技术具有较高的图像SNR和CNR,更易认识辨别瘘管和内口,可以作为一种新的无创性磁共振成像技术应用于肛瘘成像。

Objective To evaluate the accuracy of PDW PFS sequence in displaying the perianal fistulas and definition of the PDW PFS images,and discuss the application value of PDW PFS sequence in the perianal fistulas.Materials and Methods 20 patients of the perianal fistulas confirmed by surgery received MR scans with the anorectal water plug in order to dilate the anal canal and rectum.The MR sequences included T1WI,T2W SPAIR and PDW PFS.The numbers of fistulas,internal openings and perianal abscesses were evaluated and compared among the above MR sequences,and fistula signal intensity（SI）,signal to noise ratio（SNR） and contrast to noise ratio（CNR）of fistula and the surrounding muscles were measured and compared between PDW PFS and T2W SPAIR sequences.Results On MRI examinations,the PDW PFS sequence had the highest accuracy of fistulas（100%）,internal openings（95.7%） and abscesses（100%）.Kruskal Wallis test revealed significant difference in displaying the fistulas（χ2=6.95,P0.05） and the internal openings（χ2=31.53,P0.05） in these sequences.The PDW PFS sequence was the best method in displaying the fistulas and the internal openings.The SI,SNR and CNR of PDW PFS images were significantly higher than that of T2W SPAIR images（P0.05）.Conclusion PDW PFS sequence has higher SNR and CNR,and more easily identify the perianal fistulas and the internal openings.The PDW PFS can be used as a new kind of noninvasive magnetic resonance imaging technique for the patients with perianal fistulas.