[Value and related factors of preoperative diagnosis of extramural vascular invasion of rectal cancer by 3.0T magnetic resonance imaging].

Objective: To evaluate the value of preoperative diagnosis of extramural vascular invasion (EMVI) of rectal cancer with 3.0T high-resolution magnetic resonance imaging (MRI) and the MRI-related factors of EMVI in rectal cancer. Methods: The clinical and imaging data of 40 patients with rectal cancer were retrospectively analyzed. The postoperative pathological diagnosis was used as the gold standard to evaluate the diagnostic efficacy of preoperative diagnosis of EMVI of rectal cancer by high-resolution MRI, and to analyze the relationship between the EMVI and clinical and MRI features. Results: Of the 40 patients, 19 cases were diagnosed as positive EMVI and 21 were negative by MRI. Pathological diagnosis of EMVI was positive in 10 cases and negative in 30 cases. The sensitivity, specificity and accuracy of MRI in the diagnosis of EMVI were 100%, 70.0% and 77.5%, respectively. Preoperative MRI and postoperative pathology were moderately consistent in the diagnosis of EMVI in rectal cancer (Kappa=0.538, P<0.001). Pathological EMVI positivity were related to tumor size under MRI examination (P=0.028), degree of differentiation (P<0.001), depth of invasion (P=0.002), lymph node metastasis (P=0.001), liver metastasis (P=0.011), tumor apparent diffusion coefficient (ADC) value (P=0.010) and exponential apparent diffusion coefficient (eADC) value (P=0.003). It also related to extramural nerve invasion by pathological examination (P=0.005). Conclusion: According to the EMVI imaging score of rectal cancer, preoperative MRI has a high value in the diagnosis of EMVI of rectal cancer.