Services - MRA
MRA (Magnetic Resonance Angiography) refers to a study in which blood vessels are studied without the limitation of soft tissue superimposition. It represents the non-invasive version of an invasive conventional catheterization obtained on an MRI machine. Just like all magnetic resonance studies, MRA instead of using ionizing radiation uses magnetic fields and radiofrequency pulses.
The intravenous contrast used for MRA studies is gadolinium-based, not iodine-based, and is not nephrotoxic. However, in patients who have compromised kidney function defined as a glomerular filtration rate (GFR) of 30 or less, gadolinium-based contrast should only be used with the approval of a nephrologist when the potential benefits of the study outweigh the risks.
Both arteries (MRA) and veins (MRV) can be evaluated using different techniques.
- If your study requires the use of intravenous (IV) contrast, your last meal should be no less than four hours before the study.
- A good hydration regime the day before the study as well as the day of the contrast media injection is highly recommended.
- The American College of Radiology (ACR) protocol requires a pre-medication regime for patients with a history of allergies to any IV contrast.
- A recent creatinine level of no more than six weeks is required for patients with one of the following: age 60 or older, hypertension, diabetic, or existing renal condition.
- MRCP Studies: Fasting is required for patients with a gallbladder.
- Renal Patients: Gadolinium based agents are not toxic to the kidneys. However, we must evaluate a recent (not older than six weeks) creatinine level and calculate your GFR (glomerular filtration rate) to avoid risk of NSF (Nephrogenic Systemic Fibrosis)
- GFR less than 30 – cannot receive IV contrast media
- GFR 30 to 35 – authorization from primary doctor or nephrologist is required
- GFR greater than 35 – can receive IV contrast media
- We offer sedation services in MRI for pediatric patients unable to lie still and adult claustrophobic patients for an additional fee not covered by medical insurance, established by the physician in charge. Please verify with our personnel for availability.
- Patients with MRI conditional pacemakers can undergo scanning for those models that are designated by Medtronic, Boston Scientific, and St. Jude. Please contact our Communication Center for more information.
- Non MRI compatible intracranial aneurysm clips.
- Patients with metallic prosthetic material and biomedical implants must provide manufacturer documentation to verify compatibility.