The benefits of getting an accurate diagnosis and treatment plan generally outweigh the few risks associated with undergoing a CT angiogram. The main risks associated with CT angiogram: Radiation Exposure: The radiation from the X-rays during a CT scan is equivalent to receiving up to five years of natural background radiation and is thus considered minimal. However, there is always a slight risk for cancer from repeated exposure to radiation and thus we try to minimise the number of scans people undergo, particularly if another non-X-ray based imaging modality will provide similar information. Kidney injury: The contrast media used to visualise the artery on the CT scan is excreted through your kidneys. Patients with underlying kidney disease may suffer a further deterioration in their kidney function as a result of the contrast injuring the kidney filtration system. This is temporary in the vast majority of cases, but can occasionally cause permanent damage to the kidneys leading to the requirement for dialysis. Prior to your CT angiogram your kidney function will be assessed to guide your requirement for prophylactic therapy to help prevent this complication. Allergic reaction: Some people may have an allergy to the contrast media or other materials used during these procedures which has not been previously identified. The majority of these reactions are self-limiting and mild, causing hives or a rash. On rare occasions (1:100,000) an anaphylactic reaction can occur requiring emergency treatment.