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.

Objective: To investigate the diagnostic value of whole liver CT perfusion imaging in the quantitative evaluation of hemodynamic changes before and after transcatheter arterial chemoembolization (TACE). Methods: Twenty-six patients with hepatocellular carcinoma underwent TACE therapies were recruited. Whole -liver computed tomographic perfusion imaging (CTPI) was performed 2~3 days before TACE and 1 month after TACE. We measured the following perfusion parameters: hepatic arterial perfusion (HAP), portal venous perfusion (PVP), total liver perfusion (TLP), hepatic arterial perfusion index (HAPI), and time-to-peak (TTP).The F-test, t-test and Rank sum test were used for statistical analysis. Results: A total of 34 HCC lesions were detected. According to the deposition of lipiodol after TACE, they were divided into a lipiodol dense group (21) and a lipiodol light group (13). The length of hepatocellular carcinoma lesions after TACE showed a decreasing trend compared with preoperative TACE. The lesions in the lipiodol dense group had smaller lesions than those in the lipiodol light group. The preoperative and postoperative longitudinal diameters were (3.12 ± 0.58) cm vs. (1.93 ± 0.79) cm, (2.98 ± 2.01) cm vs. (2.58 ± 2.00) cm, the differences were statistically significant (t = 15.1, 8.65, P < 0.05). The preoperative HAP and HPI of the lipiodol dense group were the highest, and the peritumoral within 1cm was higher than that of the surrounding liver parenchyma. The PVP, TLP, and TTP were highest in the surrounding of liver parenchyma, and 1 cm higher than the tumor area in the background. The corresponding perfusion parameters were statistically significant (P < 0.05); HAP and HPI were 1 cm higher than the surrounding liver parenchyma. After the operation, PVP, TLP and TTP were lower than the background liver parenchyma, the difference was statistically significant (P < 0.05); HAP and HPI decreased by 1 cm after the operation, and the PVP, TLP, and TTP increased. There was no significant difference after operation in the blood perfusion of background liver parenchyma (P ˃ 0.05). The HAP and HPI decreased, and the PVP and TTP increased in the lipiodol light group after operation (P < 0.05). There was no significant difference between the other two regions (P ˃ 0.05). Conclusion There was no blood perfusion in the lipiodol deposition area after TACE. The perfusion volume of hepatic artery in the peritumoral 1 cm and lipiodol light group decreased and the portal venous perfusion increased. CTPI can quantitatively evaluate blood perfusion state, which is of great significance for the determination of treatment plans before TACE treatment to assume the postoperative therapeutic effect in liver cancer.