Objective:To analyze the computed tomography (CT), high-resolution magnetic resonance imaging (HR-MRI), diffusion-weighted imaging (DWI) manifestations and parameters of postoperative anastomotic recurrence in rectal cancer patients, and to explore their diagnostic value for recurrence.MethodsPatients with suspected anastomotic recurrence after rectal cancer surgery in Ziyang Central Hospital from January 2020 to December 2022 were selected as the study subjects, all of whom underwent CT, HR-MRI, and DWI examinations. The diagnostic value of CT, HR-MRI, DWI imaging findings, parameters [CT value, signal intensity value, contrast noise ratio (CNR), average apparent diffusion coefficient (ADC) during plain scan, arterial phase, venous phase] in the diagnosis of anastomotic recurrence after rectal cancer surgery was analyzed.ResultsA total of 103 patients with suspected anastomotic recurrence after surgery for rectal cancer were included in the study. Pathological examination confirmed that 62 cases had recurrence and 41 cases had no recurrence. CT imaging findings of recurrent patients: patients with anastomotic recurrence after rectal cancer surgery have narrowed anastomotic gaps, irregular thickening of the outer edge, and involvement of pelvic tissues and organs; HR-MRI imaging findings: the intestinal wall in the surgical area of patients with anastomotic recurrence after rectal cancer surgery showed varying degrees of thickening, with slightly longer signals on T1-weighted imaging (T1WI) and longer signals on T2-weighted imaging (T2WI). The enhanced scan showed significant enhancement. Patients with no anastomotic recurrence after rectal cancer surgery showed only mild enhancement in the T1WI signal area, which was fibrous scar tissue; DWI imaging findings: patients with anastomotic recurrence after rectal cancer surgery showed slightly high or high signal intensity on DWI and low signal intensity on ADC maps. Patients with no anastomotic recurrence after rectal cancer surgery showed low signal intensity or slightly high signal intensity on DWI and high signal intensity on ADC maps. The CT value, signal intensity value, and CNR of recurrent patients during the arterial and venous phases were higher than those of non-recurrent patients, while the ADC value was lower than that of non-recurrent patients. The area under the curves (AUC) of CT value in the arterial phase, CT value in the venous phase, signal intensity value, CNR, and ADC value for the diagnosis of recurrence were 0.828, 0.791, 0.747, 0.801, and 0.801, respectively. The AUC of combined diagnosis of anastomotic recurrence after rectal cancer surgery was 0.920 (95% CI 0.850-0.964), with a sensitivity of 88.71% and a specificity of 87.80%. All of these were superior to the diagnosis of each imaging manifestation and parameter alone (Z=2.485, 2.304, 3.018, 2.313, 3.185, 3.759, 2.706, 2.713, P<0.05), and had good consistency with pathological results (Kappa=0.759, 95% CI 0.566-0.952).ConclusionMulti-modal imaging combined with CT, HR-MRI and DWI has higher diagnostic value for postoperative anastomotic recurrence of rectal cancer.