Usually a field of view of 6 – 8 cm is large enough, which can be achieved with a coil diameter of 5 – 6 cm. Circular coils with a diameter of 8 – 15 cm are most frequently used. This position again is uncomfortable and often the patient can hold still without moving the arm for a few image acquisitions only.Įxaminations of the head require the highest spatial resolution and should be performed only with dedicated surface coils. This position might be difficult for older patients and those with shoulder complaints.Įxcellent images can be obtained by using a temporomandibular joint coil incorporated in a head coil, but the patient must be in the lateral decubitus or prone position with the arm extended above the head. An off-center field of view is a prerequisite for this examination technique.įor examinations performed in the center of the magnetic field, the patient has to be prone with the arm extended above the head. The best results can be achieved by using small Helmholtz-type surface coils or flexible coils that keep the wrist next to the patient’s body while the patient is placed in a comfortable supine position. The position should be as comfortable as possible for the patient. The wrist is the most complex joint of the human body and poses high technical demands on diagnostic imaging, and it is here that MRI has opened new diagnostic avenues and will continue to forge the diagnostic and therapeutic approach in the future. With the right auxiliary equipment, however, the 〉small’ wrist is suitable for imaging at a high resolution by using appropriate surface coils. Furthermore, positioning in the MRI gantry is difficult and burdensome for the patient unless special coils are used. MRI is used less frequently for the wrist than for knee or shoulder since the wrist has fewer conditions with established MRI indications, such as ligamentous injuries, soft tissue and bone tumors, or inflammations.
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