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Everything you need to know about Computed Tomography (CT) & CT Scanning

Reactions and Complication

question1. How often do contrast reactions occur to IV contrast? Are there patients at increased risk?
question2. Although most iodinated contrast reactions are typically mild, what is the long term sequelae to the patient who gets a reaction?
question3. Are there specific patients or risk factors that make it more likely to get a contrast reaction?
question4. Will faster injection rates (5 cc/sec vs. 1 cc/sec) result in an increased incidence of contrast reactions?
question5. What are the categories of contrast reactions?
question6. Death is one of the potential complications of IV contrast. How often does this occur?
question7. What are the risks of IV contrast in terms of renal failure (CIN)? How often does CIN occur? How we prevent CIN?
questionDefinition and Timing of CIN

Definition of CIN:

  • An impairment in renal function occurring within 3 days after administration of CM in the absence of an alternative etiology
  • Generally defined as an increase in SCr from baseline of ≥25% or ≥0.5 mg/dL (44 μmol/L)

Timing of CIN

  • Increase in SCr within 1–2 days because of decrease GFR
  • Peak at 3–4 days after CM administration

CIN, contrast-induced nephropathy
Morcos SK.
In: Textbook of Contrast Media. 1999:135-148.

Implications of CIN

CIN may result in any or all of the following:

  • Delay in discharge of patient
  • Permanent kidney damage
  • Dialysis
  • Increased patient mortality
CIN, contrast-induced nephropathy; CKD, chronic kidney disease
Dangas G et al.
Am J Cardiol
. 2005;95:13-19.



Prevention Strategies

  • Hydrate to a target urine output of 150 mL/h in the 6 hours postprocedure
  • Avoid nephrotoxic drugs. Use prophylactic pharmacologic agents or procedures (eg, NAC, statins, ascorbic acid, hemofiltration)?
  • Minimize volume of CM
  • Consider choice of CM
question8. Who can not get IV contrast material?

Allergic Reactions


1. Part 1: Can a patient get a rash from IV contrast? Can it occur 24-36 hours post CT study?

Part 2: How do you treat the rash?

question2. Is it possible for a patient to get a delayed reaction to IV contrast?
question3. What if a patient is allergic to IV contrast material?

4. Part 1: What patients are allergic to IV contrast?

Part 2: Can we premedicate these patients and if yes what is our premedication protocol?

question5. Our patient needs the study now. What else can we do?
question6. The patient is allergic to shellfish or crabs. Can they get a IV contrast?


question1. What is contrast extravasation and how often does it occur?
question2. How do you prevent contrast extravasation?

3. Part 1: How do we treat contrast extravasation when it happens?

Part 2: Is cold compresses the rule or hot compresses?
question4. What if extravasation does occur. How often are there severe complication?


© 1999-2020 Elliot K. Fishman, MD, FACR. All rights reserved.