MRI图像融合技术在肛瘘评估中的初步应用

A pilot study of magnetic resonance image fusion technology in the evaluation of anal fistula

目的采用图像融合技术获得T2WI与T2WI-FS的融合图像,评估其在肛瘘及肛周结构显示中的优势。方法2016年6月至2018年6月,前瞻性选择中山大学附属第一医院29例肛瘘患者进行肛管磁共振(MR)检查,采用图像融合技术获取T2WI与T2WI-FS的融合图像T2WIFusion,利用Fisher score算法计算瘘管及肛门括约肌的组织间分辨力Fisher值、脂肪与肛门括约肌间的Fisher值,评估融合图像中瘘管及肛周结构的显示情况。采用改进的双刺激连续质量量表(DSCQS)对T2WI-FS、T2WI、增强3D-VIBE和T2WI-Fusion序列图像进行主观图像质量评价。结果29例患者均成功获得T2WI与T2WI-FS的融合图像T2WI-Fusion。T2WI-Fusion、T2WI瘘管与括约肌间Fisher均值分别为6.46、3.31,T2WI-Fusion图像对瘘管的显示优于T2WI序列图像(P<0.001)。T2WI-Fusion、T2WI-FS脂肪与括约肌间Fisher均值分别为10.61、2.45,T2WI-Fusion图像对括约肌的显示优于T2WI-FS序列图像(P<0.001)。T2WI-Fusion对瘘管与括约肌的图像质量评价总评分均高于T2WI-FS、T2WI、增强3D-VIBE序列(P<0.001)。结论MRI图像融合技术同时具备T2WI及T2WI-FS的优势,无需增加扫描序列及扫描时间,且操作简单,花费时间短,显著提高病变及肛周解剖结构的对比度和图像质量。

Objective To get the fusion image of T2 WI and T2 WI-FS sequence by applying the image fusion technology, and evaluate the advantages in anal fistulas and surrounding structures. Methods From June 2016 to June 2018, twenty-nine patients with anal fistula were collected prospectively in the First Affiliated Hospital, Sun Yat-sen University. All the patients received anal magnetic resonance imaging(MRI) examination. T2 WI and T2 WI-FS images were used to generate fusion images(T2 WIFusion). The discriminability of fistula, perianal sphincter, and perianal fat in T2 WI, T2 WI-FS, and T2 WIFusion images was quantified with Fisher’s scoring algorithm. For subjective visual image assessment by researchers, five-point scale scores were determined using a modified double-stimulus continuous qualityscale(DSCQS) test to evaluate T2 WI-FS, T2 WI, enhanced axial 3 D-volumetric interpolated breath-hold examination(3 D-VIBE), and T2 WI-Fusion sequence images. Results Mean Fisher scores for fistulas vs sphincters obtained from T2 WI-Fusion images(value=6.46) were significantly higher than those from T2 WI images(value=3.31)(P<0.001). Mean Fisher scores for sphincters vs fat from T2 WI-Fusion images(value=10.61) were significantly higher than those from T2 WI-FS images(value=2.45)(P<0.001). T2 WIFusion images showed better whole anal fistula and sphincter discriminability than that of T2 WI-FS, T2 WI and enhanced 3 D-VIBE images(P<0.001). Conclusions MRI fusion technology combines the advantages of the T2 WI and T2 WI-FS images without increasing scan sequence and scan time. This technology is easy to operate and timesaving, and can significantly increase the anal fistula and sphincter discriminability and improve the imaging quality.