先天性肛门直肠畸形患儿横纹肌复合体的MRI研究

The MRI study of the sphincter muscle complex in congenital anorectal malformations

目的了解先天性肛门直肠畸形(ARM)患儿横纹肌复合体(SMC)发育状态及其与排便功能的关系。方法 64例患儿进行盆腔 MRI 检查,其中对照组25例,为无直肠肛管疾病,因其他疾病需进行盆腔 MRI 检查者,ARM 组39例。应用不同序列体部相控阵列线圈或头部线圈 MRI 对SMC 从多个层面进行观测及定量分析,评估其发育状态与排便功能的关系。术后39例 ARM 患儿均进行1～6年的随访,对30例5岁以上患儿进行主、客观排便功能的检查。结果对照组 SMC 宽度绝对值为(3.63±0.22)mm,与年龄有相关性(r=0.998,P<0.01);SMC 宽度相对值为0.50±0.02,与年龄无相关性(r=0.265,P>0.05)。低、中位 ARM 患儿肌肉发育指数(MI)分别为0.49±0.05和0.47±0.05,发育良好;高位 ARM 患儿 MI 为0.28±0.06,仅部分 SMC 发育不良。30例5岁以上的随访患儿中,当 MI≤0.18时,直肠肛管收缩压差较 MI>0.18时明显降低[分别为(0.85±0.20)、(2.24±1.02)kPa,t=3.55,P<0.01],肛管高压区长度明显缩短[分别为(10.88±3.64)、(20.26±4.34)mm,t=5.18,P<0.01],直肠肛管角>100°,7例中5例 ARM 术后出现肛门失禁。当MI>0.18时,直肠肛管角<90°,23例中21例 ARM 术后排便功能好。结论 MRI 检查能清楚地显示对照组和 ARM 组患儿 SMC 发育状态,MI 可以作为 SMC 发育的量化指标,并可用于评估 ARM 患儿SMC 的发育状态,当 MI≤0.18时可作为 SMC 发育不良的客观指标。

Objective To evaluate the development of the sphincter muscle complex （SMC） and defecation function in pediatric patients with congenital anorectal malformations（ARM）. Methods A total of 64 children underwent MRI, among whom 39 were patients with ARM, and the others were patients without ARM undergoing MRI because of other dieases. The dimensions of the SMC in different planes were evaluated with different sequences and coils. The relationship between the SMC development and the defecation function was investigated. Results In control group, the absolute value of SMC width was （ 3.63±0. 22） mm ,which had a high correlation with age （ r = 0. 998, P 〈 0. 01 ）. The relative value of SMC width was 0.50±0. 02, which had low correlation with age （r = 0. 265, P 〉 0. 05 ）. The SMCs in intermediate ARM patients[ muscle index （MI） = 0. 47±0. 05 ] and low ARM patients （ MI = 0. 49±0. 05 ） were well developed. The SMCs in a portion of patients with high ARM （ MI = 0. 28±0.06 ） were poorly developed, when MI ≤0. 18, anorectal contraction pressurewas significantly lower （ t = 3.55, P 〈0. 01 ） compared to those with MI 〉0. 18[ （0. 85 ±0.20） vs （2. 24±1.02） kPa]. The length of anal canal with high-pressure[ （ 10. 88±3.64） vs（20.26±4. 34） mm] was shorter（ t = 5. 18 ,P 〈 0. 01 ） than that of another group, the anorectal angle was more than 100 degrees, and the incontinence was found in 5 of 7 cases. When MI 〉0. 18, the anorectal angle was less than 90 degrees, and normal continent function was found in 21 of 23 cases （91%）. Conclusion MRI can be employed to evaluate the development of SMC in patients with ARM, MI was an objective criteria to evaluate the development of SMC. When MI≤0. 18, maldevelopment of SMC will be highly suspected.