Introduction
Magnetic resonance imaging (MRI) of the foot is a type of imaging that does not require X-rays and can be helpful if the findings are unclear. In this procedure, hydrogen molecules (protons) in the body are excited, which then emit a signal that is measured and converted into images. If, for example, a fracture could not be excluded with certainty or if the age of a fracture is to be determined, MRI is the method of choice.
Ligaments and muscles of the foot can only be well visualized by MRI if a torn ligament is suspected. In addition, an MRI is often performed to plan an operation. However, there are situations in which an MRI cannot be performed, e.g. if the patient wears a pacemaker.
An MRI of the foot is necessary if a fracture cannot be reliably ruled out in X-rays or computed tomography (CT) or if the findings are unclear. Furthermore, the age of a fracture can be estimated with the MRI. Since the soft tissue in particular, i.e. the ligaments and muscles, can also be depicted well in the MRI, this method is well suited to rule out the possibility of ligament rupture in the foot or to exclude the involvement of ligaments in a fracture. Chronic inflammation of muscles can also be depicted well in the MRI of the foot.
Indications
An MRI of the foot is necessary if a fracture cannot be reliably ruled out on X-ray or CT or if the findings are unclear. Furthermore, the MRI can be used to assess the age of a fracture. Since the soft tissue in particular, i.e. the ligaments and muscles, can also be depicted well in the MRI, this method is well suited to rule out the possibility of a torn ligament or the involvement of ligaments in a fracture.
Chronic inflammation of muscles can also be depicted well in the MRI of the foot. Before the examination, there is an informative discussion with the doctor performing the examination, in which he explains the course of the examination to the patient and makes sure that the MRI is the appropriate method for examining the clinical picture. He also asks about possible risks for the examination such as a pacemaker, metal splinters in the body or a cochlear implant.
Before the MRI of the foot, the radiologist decides whether a contrast medium is necessary for the specific problem and, if so, provides information on this. Next, the patient must remove jewelry and metallic objects (glasses, hair clips, belts with buckles or bras with metallic underwiring). Sometimes the patient is given a patient shirt to put on, although it is not unusual for the patient to be allowed to keep the clothes on if they do not affect the quality of the examination and there is no danger that they could be attracted by the magnet.
Then the patient lies down on the table with his feet in the direction of the tube. The foot is positioned so that the patient can lie as still and comfortable as possible without distorting the images by wobbling. Ear protection is also put on.
A special coil, a box with metal coils that improve the quality of the recording, can be used, which is placed over the foot. If contrast medium is used in the MRI of the foot, a venous access is placed before the examination. Now different sequences are made, whereby the tube emits loud, throbbing noises.
In the MRI of the foot, only the foot is inserted into the tube, parts of the leg may also be in the tube. However, not the whole body and especially not the head is inside the tube. Patients who are afraid of narrow spaces should therefore have no problems with the MRI of the foot.
Whether or not you have to undress during the MRI of the foot depends on the practices in the practice or hospital. It can be independent of the examination that each patient must undress except for underwear and then put on a patient shirt. In some departments, however, it is also handled in such a way that the patient can wear metal-free clothing (cloth trousers, bra without underwire) if only a picture of the foot is taken.
