Contrast-Enhanced Photon-Counting Detector CT (PCD-CT) for the Local Staging of Rectal Cancer

Inclusion Criteria: * Adult patients 18 to 99 years of age * Patients with proven rectal cancer clinically referred for staging pelvic MRI and contrast-enhanced CT of the abdomen and pelvis (for evaluation of liver and peritoneal disease) * Endoscopic or imaging report that tumor is 2 cm or larger * Patients who are able and willing to sign the informed consent * Negative pregnancy test if subject is of child-bearing age (females of child-bearing potential will be screened for pregnancy using a urine pregnancy test, which will be administered by the unit study coordinator at no cost to the patient) Exclusion Criteria: * Minors less than 18 years old * Known mucinous adenocarcinoma (may not enhance well) * Patient unable to provide written informed consent * Pregnancy * estimated Glomerular Filtration Rate (eGFR) ≤ 60 * History of prior moderate or severe contrast reaction including unresponsiveness, severe respiratory distress, convulsions, arrhythmia, cardiopulmonary distress, progressive angioedema, laryngeal edema, dyspnea, bronchospasm, symptomatic tachycardia, symptomatic bradycardia, hypotension, hypertensive crisis * Any history of premedication prior to iodinated contrast * Hip replacement/prosthesis * Patients that consent to participation but do not undergo their clinically indicated MRI scanning for any reason (e.g., bad IV, infiltration, reaction, change in indication)