RadNet medical imaging centers offer physician-centered care. We understand when it comes to radiology referrals, accuracy is essential. But it’s just one part of the picture. We also know that fast turnaround, dedicated support and responsive service and processes are equally important. When you refer patients to us, you can be sure they will receive the highest level of care.
CT & MRI IV Contrast Guidelines
We at VRI recognize that contrast administered during imaging studies is not without risk. In order to prevent contrast induced nephropathy in CT, nephrogenic systemic fibrosis in MR, and contrast reactions in both CT and MR, we have briefly outlined our protocol below to maximize safety while achieving the highest diagnostic accuracy. Our guidelines are informed by the latest American College of Radiology’s Manual on Contrast Media, Version 10.3.
CT
For CTs with contrast, renal function tests should be obtained within 90 days for patients with diabetes, hypertension requiring medical therapy, a history of renal disease, or that may have possible renal dysfunction.
- for eGFR > 60, a full dose of contrast will be administered.
- for eGFR 40-60, pre-scan IV hydration and the use of the lowest possible dose of contrast for an adequate study will be administered.
- for eGFR 30-39, order will be reviewed and the referring physician may be contacted to ensure contrast is absolutely necessary; if so, pre-scan IV hydration and the use of the lowest possible dose of contrast for an adequate study will be administered.
- for eGFR < 30, contrast will not be used due to the significant risk of contrast induced nephropathy.
- for patients in chronic renal failure on dialysis and no reasonable expectation of native renal function, contrast may be used.
MRI
For the vast majority of MRI examinations with contrast (Dotarem at our facilities), renal function tests are no longer recommended unless the patient is undergoing a rare specific liver examination requiring Eovist contrast (rare). In that case, laboratory tests should be obtained within 90 days for patients with diabetes, hypertension requiring medical therapy, a history of renal disease, or that may have possible renal dysfunction.
- eGFR >30, both Dotarem and Eovist can be administered. Please note neither agent has ever had a nonconfounded case of nephrogenic systemic fibrosis.
- eGFR < 30 & not on dialysis, Eovist not recommended, but could be used if referrer believes the benefits outweigh the risks. Dotarem can be administered.
- on dialysis, Dotarem can be administered, but dialysis should occur within 24 hours. Eovist not recommended, but could be used if referrer believes the benefits outweigh the risks. Dialysis should occur within 24 hours.
Allergy Premedication Guidelines
No pretreatment needed
- Vast majority of patients. Existing allergies, even anaphylactic ones, unrelated to specifically iodinated contrast no longer require premedication.
Premedication needed (50mg Prednisone PO 13, 7 and 1 hour before injection & 50mg Benadryl PO within 1 hour of injection)
- Existing mild reaction to iodinated contrast i.e. hives, nonanaphylactic reaction
IV contrast contraindicated
- Prior anaphylaxis to iodinated contrast
MRI Contraindications
MRIs are contraindicated if there are:
- Pacemakers or other implanted pump devices.
- Metallic debris in the soft tissues of the orbit.
- Older intracranial vascular aneurysm clips (most modern clips are MRI compatible and can be cleared by our techs if the clip model is identified).
MRIs are NOT contraindicated with:
- Orthopedic implanted hardware (joint replacements, spinal fusion, etc.).
- Soft tissue shrapnel (except for within the orbit).
- Non-intracranial vascular stents.
Please call any of our offices if you have any questions regarding the suitability of your patient for MRI examinations and we will be happy to assist you.