Patient Safety for Referring Health Providers
The use on contrast agents in medical imaging continues to evolve. In some clinical settings like renal colic, contrast was required for diagnosis (e.g. IVP). Now obstructive uropathy can be made more accurately without contrast with a “renal stone” CT study. In other settings, contrast is not only needed but need to be delivered during a particular time so that optimum visualization of pathology can be achieved.
Adverse reactions with certain drugs, namely metformin, require careful screening. Reduced renal function, diabetes and the use of iodinated contrast requires screening creatinine in certain populations to determine where the patient stands on a risk risk benefit basis.
Finally, the recently described risk of nephrogenic systemic fibrosis (NSF) associated with gadolinium chelates has made screening patients at risk mandatory before the use of gadolinium contrast.
We at RMR ascribe to those recommendations promulgated by the American College of Radiology. The following links go into detail regarding these and other topics. We also include links to GFR calculators that we use at our hospitals and imaging centers which help in assessing patient risk for contrast induced nephropathy as well as nephrogenic systemic fibrosis.
Finally, the risk of anaphlactoid to contrast agents thankfully remains extremely low in the general population, but certain populations do carry a greater risk for this severe reaction.
- ACR Manual on Contrast Media
- Contrast Induced Nephropathy (CIN) See Topic 9; page 33
- Metformin (Glucophage) and iodinated contrast media See Topic 10; page 45
- Nephrogenic Systemic Fibrosis (NSF) and gadolinium contrast media See Topic 15; page 85
- FDA Newsletter on Gadolinium Agents
- Allergic reactions to contrast media For Iodinated See Topic 7; page 22; For Gadolinium See Topic 14; page 81
- CT_GFR_Calculator (Please right click on this Excel file to download to your computer using “Save Link As”)
- GFR Calculator for MRI (Please right click on this Excel file to download to your computer using “Save Link As”)
- Contact an RMR Radiologist
As the use of medical imaging utilizing radiation continues to expand, concerns regarding population dose and in particular individual dose are being raised, and rightly so. Medical imaging constitutes the number one source of non-natural radiation to the United States population. It is imperative that medical practitioners continue to strive for the judicious use of these studies. This is especially true with children and pregnant women, who are known to be more susceptible to the adverse effects of medical radiation. On the other hand, over reaction to radiation risk should also be avoided, as the correct use of imaging can make a significant and potentially life saving difference to the patient. The tried and true acronym of ALARA should always be heeded: As Low AsReasonably Achievable. If you are ever in doubt, don’t hesitate to confer with one of the radiologists at RMR. Radiation safety is an integral part of our training and ongoing practice.
While MRI does not use ionizing radiation and is generally safe for use in most patients, there are several relative and a few absolute contraindications that must be taken into consideration when prescribing an MRI study. Given the magnetic field strength required for even a low field MRI scanner, you wouldn’t want to walk in the room with a box of nails. Similarly, you wouldn’t want to bring in your favorite electronic device into the imaging room. This is generally true for most medically implanted devices such as pace makers, pain management devices and pumps. Please contact one of our radiologists if you have a concern regarding your patients particular situation.