Colorectal cancer is the third most commonly diagnosed cancer in the world. The 5-years survival rate depends on the tumor stage and grade at patient presentation. Individual treatment strategy based on the tumor stage and grade should be applied to improve the prognosis, So the pre-operative diagnostic evaluation and grading of colorectal cancer are important.

Diagnosis of cancer colon is usually based on colonoscopy which provides direct visualization of the lesions and allows for biopsies. However the pre-operative specimens from endoscopic biopsies sometimes fail to grade tumor because of the lack of sufficient tissue. Recent improvements in computed tomography have allowed for minimally invasive evaluation of cancer colon. Quantitative iodine density measurement can be used to differentiate low and high grade colorectal cancer. However, debate continues regarding the correlation between tumor grade and computed tomography perfusion parameters of colorectal cancer demonstrating the need for further investigation in this area of research.

Inclusion Criteria:

• Any patient with primary colorectal mass

Exclusion Criteria:

• Colorectal mass pathologically proved to be benign Female patient at child bearing period with suspected pregnancy Raised renal chemistry Hypersensitivity to contrast.

Patients with colorectal mass pathologically proved to be adenocarcinoma by colonoscpoic biopsy