Spectral CT was used to prospectively collect medical images and clinical data related to colorectal cancer, evaluate the effect of image quality in the diagnosis of colorectal cancer, and evaluate the application value in the accurate staging of colorectal cancer, so as to provide a more accurate clinical basis for diagnosis, promote the development of individualized treatment, and ultimately improve the prognosis of patients.

Inclusion Criteria:

• (1) Undergo contrast-enhanced Quark energy spectral CT examination of the lower abdomen/pelvis within 1 week before treatment;(2) MSI status confirmed;(3) Age >18 years;(4) Patients with suspected colorectal cancer;(5) Patients who provided informed consent.

Exclusion Criteria:

• (1) Severe cardiac, pulmonary, or renal insufficiency;(2) Allergy to iodine-based contrast agents;(3) Inability to cooperate during the CT examination;(5) Poor image quality from Quark spectral CT scans;(6) Pregnant or lactating women.