By Alpesh D. Patel, MD
Magnetic Resonance Imaging (MRI) uses magnetic energy to derive images of the body for diagnostic purposes. For many issue indications, this is the ultimate form of imaging of the body. MRI applications are vast but the modality is most commonly used for imaging of the brain, head and neck, spine, and the extremities. It is also excellent for imaging of the abdomen and heart.
Magnets Make a Difference
Many factors go into producing high- quality images and the magnetic field strength of the MRI magnet is one of the most important factors. The quality of
the images produced by MRI is directly proportional to the strength of the magnet. Up to a point, the higher the magnetic field strength, the better the quality of the image, and therefore, the better its diagnostic capability.
One of the most common limitations of MRI for the general population has been claustrophobia. Most high-field-strength MRI units are enclosed, which makes many patients feel claustrophobic and makes the unit untenable for certain patients. Also, since most exams take 30 to 40 minutes to complete, the size of the population that was unable to tolerate MRI and not benefit from its outstanding diagnostic capabilities was considerable.
Open MRI units were developed specifically for this large population. However, in the past, these units typically had very low-field-strength. As a result, image quality suffered considerably. Because of the suboptimal diagnostic quality of the images, use of these units fell out of favor. Unfortunately, some of these low- field MRI units are still around.
Open MRI Units are Cutting out Claustrophobia for Good
Recently, technological advancements have led to the development of high-field open MRI units. These newer units combine a wide, open design to mitigate claustrophobia and simultaneously maintain high-field-strength (and thus maintain the high diagnostic quality of the images). These high-field open units are very well tolerated by most claustrophobic patients and can be used even for patients without claustrophobia, as the image quality is excellent.
Because of the expense of these units, there are very few of them available. It is imperative for patients who can’t tolerate high-field closed MRI units to make sure that they are imaged in a high-field open MRI unit.
When scheduling a MRI, it is important to question the imaging facility in order to be certain that the open unit they will have their imaging in is a high-field open unit.