In this retrospective study is to establish a diagnostic model for rectal adenoma canceration. The model will include multimodal comprehensive HR-T2WI morphological score, IVIM functional imaging and radiomics features, and clinical indicators such as tumor markers, serum Gelsolin protein and peripheral blood inflammatory cell ratio. It can be to provide accurate diagnostic information for patients before surgery, which is of great value for formulating personalized treatment plans and improving the prognosis of patients.

Imaging tests is the main method for evaluating rectal mass, especially MRI, which has been widely used in the preoperative diagnosis of rectal mass disease due to its very good soft tissue resolution. Previous studies in our group found that HR-T2WI-based radiomics, HR-T2WI-based morphology, and IVIM-based functional imaging can be used for the diagnosis of adenoma canceration. In addition to imaging, other tests, such as peripheral blood tests, can also reflect the development and progression of adenocarcinoma by counting tumor markers (colorectal tumor markers mainly CEA, AFP, CA199, CA724, CA50, CA242), inflammatory cell ratio (lymphocyte/C-reactive protein ratio, neutrophil/lymphocyte ratio, lymphocyte/monocytes ratio), and special types of proteins (such as coagulant protein).This study identifies the progression of adenoma to carcinoma by analyzing the combined cellular, morphological, and functional changes in adenoma carcinomas, with the expectation that multimodal co-diagnosis will improve the accuracy of clinical diagnosis.

Inclusion Criteria:

1. surgical resection
2. pathologically confirmed rectal adenoma or rectal adenoma with canceration
3. rectal MRI examination including IVIM-DWI, within two weeks before surgery

Exclusion Criteria:

1. preoperative treatment
2. poor image quality, including intestinal gas or fecal artifact and IVIM image fitting error
3. no surgical resection but colonoscopy
4. pathologically confirmed rectal cancer.

Collect patients who come to our hospital for surgery due to rectal mass, and preoperative colonoscopy is diagnosed as adenoma or suspected adenoma cancerous, and did not receive any treatment before surgery. Exclusion criteria: patients with malignant tumors of other organs, patients who have received neoadjuvant chemoradiotherapy before surgery, patients with other acute and chronic inflammation, and claustrophobia.