When staging prostate cancer, determining whether there is extraperitoneal invasion is an important indicator for classifying limited and progressive prostate cancer, and there is a great difference in clinical treatment between these two, so when choosing treatment for prostate cancer patients and evaluating expected outcomes, it is important to first accurately identify whether there is extraperitoneal invasion. In general, tumor growth into the periprostatic fat is a more definite indication of peri-peritoneal breakthrough. In addition, peri-peritoneal thickening with irregular and limited prominence is also an indication of peri-peritoneal breakthrough. It has been reported in the literature that irregular protrusion of the envelope has a 75% probability of envelope breakthrough, while smooth protrusion has less than a 25% probability. The efficacy of using 3.0T MR scanner to diagnose pericardial invasion is further improved, allowing detection of pericardial invasion <2 mm in extent. Other manifestations related to prostate cancer staging are: periprostatic neurovascular bundle invasion, seminal vesicle invasion, pelvic floor muscle invasion, lymph node metastasis, and bone metastasis, all of which can be evaluated more accurately by MRI within the pelvic scan. The posterior lateral neurovascular bundle of the prostate is susceptible to tumor invasion, which manifests as prominent soft tissue with loss of normal neurovascular bundle, limited thickening of the neurovascular bundle or bilateral asymmetry, which is better observed on axial T1W I. The sensitivity, specificity and accuracy of magnetic resonance in diagnosing neurovascular bundle invasion were 68%-81%, 59%-72% and 64%-76%, respectively. Limited T2WI signal hypoplasia, wall thickening and loss of prostatic seminal vesicle angle in the seminal vesicle gland are signs of seminal vesicle invasion, and coronal and sagittal images are better for showing invasion of the seminal vesicle base. Hemorrhage, endocrine therapy and post-radiotherapy changes can also cause a decrease in the T2WI signal of the seminal vesicle gland, which reduces the diagnostic accuracy to some extent. The sensitivity of MRI to predict seminal vesicle invasion has been reported to be 22% and the specificity to be 88%. Lymphatic metastasis is the most common metastatic route for prostate cancer, and lymph node metastasis can occur in 7-23% of prostate cancers. Therefore, when performing MRI in patients with suspected prostate cancer, the scan should include the entire pelvis, from the pelvic floor to the level of the skeletal vascular bifurcation, which is also the area where metastases occur most frequently. Lymph node metastases are better observed by axial surface lipid suppression T2WI and appear as high-signal nodules with clear margins, sometimes fusing into a mass. Lymph node metastases can generally be considered in the smallest diameter >1.0 cm, but pathological findings show that a significant number of lymph nodes <1 cm also have metastases. The typical bone metastasis of prostate cancer is osteogenic, showing very low signal in T1WI and very low signal in T2WI, and osteolytic metastasis shows low signal lesions in T1WI and high signal lesions in T2WI. In a study of 71 patients with prostate cancer, the sensitivity, specificity and accuracy of MRI in diagnosing bone metastases were 94.7%, 100% and 98.6%, respectively, higher than those of isotopes 89.5%, 84.6% and 85.9%O, but the scanning range was limited.