目的:探讨术前影像学检查手段对于中低位直肠癌侧方淋巴结转移诊断、手术中侧方淋巴结的清扫策略及患者预后的意义。方法:本研究纳入79例行侧方淋巴结清扫的中低位直肠癌患者共计112枚侧方淋巴结，探讨其术前影像学中侧方淋巴结影像学特征、临床特点与侧方淋巴结转移的关系。结果:38例（48%）患者的术后病理证实为侧方淋巴结转移。转移阳性侧方淋巴结直径与转移阴性侧方淋巴结相比显著增大（n P<0.01）。单因素分析发现患者的性别、术前放化疗、T分期、淋巴结最大短径≥7 mm、淋巴结最大长短径之比、密度或信号不均匀、边缘不规则、无淋巴门、发现钙化或坏死与直肠癌侧方淋巴结转移均有关（均n P<0.05）。多因素分析显示，肿瘤分化差（n P=0.006）、侧方淋巴结最大短径≥7 mm（n P=0.024）、密度或信号不均匀（n P=0.022）是侧方淋巴结转移的独立危险因素。n 结论:肿瘤分化差、侧方淋巴结最大短径≥7 mm、密度或信号不均匀是中低位直肠癌侧方淋巴结转移的独立危险因素。“,”Objective:To evaluate CT and or MRI imaging in the diagnosis of lateral lymph node metastasis in patients of middle and low rectal cancer.Methods:In this study, 112 lateral lymph nodes were harvested in 79 patients with middle and low rectal cancer. The relationship between the preoperative imaging features of the lateral lymph nodes and the postoperative pathology was evaluated.Result:Thirty-eight cases (48%) were pathologically confirmed to have lateral lymph node metastasis. The diameter of metastasis-positive lateral lymph nodes was significantly larger than that of metastasis-negative lateral lymph nodes (n P<0.01). Multivariate analysis of clinical features and imaging features found that, tumors poorly differentiated, mucinous adenocarcinoma, signet ring cell carcinoma (n P=0.006), and the largest short diameter of the lateral lymph node ≥7 mm (n P=0.024), uneven density or signal (n P=0.022) were independent risk factors for lateral lymph node metastasis.n Conclusion:Poor tumor differentiation, lateral lymph node maximum short diameter ≥7 mm, density or signal unevenness are independent risk factors for lateral lymph node metastasis in middle and low rectal carcinoma.