Test Details & Preparation
Magnetic Resonance Imaging (MRI) is a diagnostic technique that uses a combination of magnetic fields and radio waves to visualize structures within the body with improved clarity and resolution. The procedure is entirely non-invasive and usually no patient preparation is necessary. The exam lasts 30 to 60 minutes depending on the body part being scanned and is usually divided into 3 or 4 imaging segments.
One of the great advantages of the MRI system is that no x-rays are used. Tests with these magnetic fields and radio waves that are used in this imaging system have been performed over the last forty years and have shown no harmful effects. The most common exceptions to this are in patients with pacemakers, internal defibrillators or brain aneurysm clips these usually cannot be scanned in the MRI system. Scans requested on pregnant patients should be discussed with the radiologist.
In some instances, a contrast agent (gadolinium DTPA) will be administered when requested by the referring physician. All MRI studies require a written prescription or referral stating the exam being ordered and the medical necessity of the procedure.
MR Angiography (MRA)
MRA is an MR scan that images the blood vessels. This scan is usually done with the injection of a contrast agent. It is usually performed to find aneurysms, arteriosclerosis, or abnormal narrowing in blood vessels.