Are there drawbacks to MRI scans?

MRI scans are ideal for diagnosing and evaluating many conditions, but they do have drawbacks. For example:

• Many people cannot be scanned safely with MRI (i.e., because they have pacemakers). Also, some people are too big to be scanned.
• Many people are claustrophobic. For them, being in an MRI machine can be very disconcerting.
• The MRI machine makes a tremendous amount of noise. The noise sounds like a continual, rapid hammering. Patients can be given earplugs or stereo headphones in an attempt to muffle the noise. The noise is from the rising electrical current in the gradient magnets' wires as it is being opposed by the main magnetic field.
• Patients must remain very still for extended periods of time when getting an MRI scan. The exams can range from 20 minutes to 90 minutes, sometimes more. Even very slight movement can cause distorted images that will have to be repeated.
• If the area of the scan has orthopedic hardware (such as screws, plates or artificial joints) the image can have severe distortions. This hardware causes a significant alteration in the magnetic field and a uniform field is critical to good imaging.
• MRI machines are very expensive; therefore the exams are also very expensive.

Despite these drawbacks, MRIs offer almost limitless benefits.