正常直肠系膜横径的MRI解剖学研究

目的　基于核磁共振图像探讨正常成人直肠系膜横径及其影响因素。 方法　收集100例符合纳入标准的行盆腔MRI检查的成人临床资料进行回顾性分析。其中，男性42例，女性58例，年龄27~83岁。在轴位T1W1图像的精囊腺/子宫体层面上，测量直肠系膜最大横径、直肠最大横径、膀胱最大横径、双侧股骨头间距、前腹壁皮下脂肪厚度及女性子宫最大横径；对直肠系膜横径与其他测量指标之间的相关性进行统计学分析。 结果　（1）58例女性中，直肠系膜最大横径为（7.15±0.97）cm，子宫最大横径为（5.86±0.61）cm。直肠系膜横径与子宫横径无统计学相关性（P>0.05）。（2）合并男性、女性数据进行统计学分析。直肠系膜最大横径为（7.15±0.87）cm，直肠最大横径为（2.84±0.74）cm，膀胱最大横径为（8.58±1.66）cm，双侧股骨头间距为（12.79±0.96）cm，前腹壁皮下脂肪厚度为（2.01±0.76）cm。直肠系膜横径与性别、年龄以及膀胱横径无统计学相关性（P>0.05）；直肠系膜横径与前腹壁皮下脂肪厚度、直肠横径、双侧股骨头间距存在线性正相关（t=3.807、2.612、2.002，P<0.05）。以直肠系膜最大横径（Y）为应变量，前腹壁皮下脂肪厚度（X1）、直肠横径（X2）、双侧股骨头间距（X3）为自变量，得回归方程为：Y=3.500+0.389 X1+0.275 X2+0.163 X3，P<0.05，R2=0.522。 结论　直肠系膜横径与双侧股骨头间距、前腹壁皮下脂肪厚度及直肠横径有关。直肠系膜横径的观察和测量，可为直肠病变的诊疗提供影像学依据。

MRI anatomic analysis of influential factors of normal mesorectal transverse diameter in adult

Objective　To investigate the influential factors of transverse diameter of mesorectum in adults based on magnetic resonance imaging (MRI).　Methods　Clinical data of 100 patients who met the inclusion criteria and then treated with MRI on pelvic cavity were analyzed retrospectively. The 100 cases (42 males and 58 females) aged from 27~83 years old. On the axial MR T1WI, the following parameters were measured at the seminal vesicle/uterine body level: the maximal transverse diameter of mesorectum, bladder and rectum, and the interval of the bilateral femoral head, the thickness of anterior abdominal subcutaneous fat tissue, the uterus maximal transverse diameter of female. The correlation between the maximal transverse diameter of mesorectum and the above measured parameters was analyzed statistically.　Results　(1) According to the data of 58 females cases, the maximal transverse diameter of mesorectum was (7.15±0.97) cm, uterine maximal transverse diameter was (5.86±0.61) cm. There was no statistical correlation between the maximum transverse diameter of the mesorectum and the transverse diameter of the uterus (P＞0. 05). (2) The data of male and female were combined for statistical analysis: the maximal transverse diameter of mesorectum was (7.15±0.87) cm. The maximal transverse rectum diameter was (2.84±0.74) cm, and the maximal transverse diameter of bladder was (8.58±1.66) cm. The interval of the bilateral femoral head was (12.79±0.96) cm. The thickness of anterior abdominal subcutaneous fat tissue was (2.01±0.76) cm at the same level. There was no statistical correlation between the transverse diameter of the mesorectum with gender, age, and the transverse diameter of the bladder (P＞0.05). It was positively correlated with the thickness of subcutaneous fat tissue in the anterior abdominal wall, the transverse diameter of the rectum, and the interval of the bilateral femoral head (t=3.807, 2.612, 2.002, P<0.05). Set the transverse diameter of mesorectum (Y) as the dependent variable, with the thickness of anterior abdominal fat tissue (X1), rectal transverse diameter (X2), the interval of the bilateral femoral head (X3) as the independent variables, the regression equation was: Y=3.500+0.389 X1+0. 275 X2+0.163 X3, P＜0.05, R2=0.522.　Conclusions　The mesorectal transverse diameter is related to the interval of the bilateral femoral head, the thickness of fat tissue in the anterior abdominal wall and the transverse diameter of the rectum. Observing and measurement of the mesorectal transverse diameter is helpful for the clinical diagnosis and treatment of the rectal lesions.