Prior to now, we have discussed ways a doctor can get an
image of your foot in the office.
However, as we discussed, there are times when a more advanced and
detailed image is needed. Magnetic
Resonance Imaging (MRI) is a great tool to use in these situations.
In order to obtain an MRI, a patient is placed in a room
with machine containing a giant magnet.
This magnet causes the hydrogen ions in your bones, muscle, and other
soft tissue to give off a signal that can be detected by a computer. Depending on the tissue, different signals
will be given off. The computer analyzes
the signals and develops a picture. Once
the 1st picture is taken, the machine moves a couple millimeters and
takes the next picture. If you can imagine slicing up a tomato or onion, an MRI
is like slicing the foot into many individual sections. These individual slices are then grouped
together so the doctor can get a good picture of the inside of the foot.
The major benefit to an MRI is that it can show bone,
tendon, and cartilage in a very detailed image.
This can be used by the doctor as a surgical planning tool before he
takes a patient to the operating room.
MRI can be helpful to diagnose a condition, but most problems can be
diagnosed during a routine office visit without the help of an MRI. Although there are exceptions to that rule,
an MRI is not usually ordered until the doctor and patient have agreed that
surgical treatment is needed.
Another benefit to MRI is that no radiation is received by
the patient, and it does not require a dye or contrast to be injected into the
patient. MRI is a completely noninvasive
imaging technique. For these reasons,
MRIs are very safe for the patient.
On the other hand, an MRI requires you to lie motionless for
an extended period of time. If you are
moving when the slices are being taken, the image becomes distorted and
impossible to interpret. This can be
somewhat uncomfortable. In addition, if
you have metal plates or screws in your body from previous surgery, the metal
will distort the image, making it hard to see anything. For that reason, some patients may not be
able to get a useful MRI. Lastly, MRIs
are very expensive. Most insurance
providers will not pay for an MRI until multiple conservative measures have
been exhausted with no improvement in treating the patient.
