Imaging of the Wrist and Hand

, Royal Victoria Hospital, McGill University, Montrèal, Canada.

Disclosures

Medscape General Medicine. 1999;1(1) 

In This Article

Computerized Tomography (CT)

As with plain radiography and arthrography, CT employs ionizing radiation. It allows three-dimensional visualization of the carpal bones and provides soft tissue detail. Helical CT, also known as spiral CT, is a form of three-dimensional imaging that also uses ionizing radiation. Its major advantage over conventional CT is the rapidity with which it can image large areas. However, relative to conventional CT, spiral CT produces an image which is less sharp. Because the wrist and hand have relatively small anatomic areas and because a high degree of detail is required for accurate assessment, conventional CT is often more practical than spiral CT for evaluation of wrist/hand trauma.[17]

As in other anatomic regions, transaxial CT imaging of one or both wrists may be performed. Images are obtained while the patient is prone and with arm(s) stretched above the head. Because of the size and flexibility of the wrist, it is possible to obtain direct scans of the wrist in the coronal and sagittal planes. (CT scans acquired directly are sharper than reconstructed images and therefore easier to interpret.) With the patient prone, the elbow in 90[infinity] of flexion above the patient's head, and the palm face down on the CT table, direct sagittal scans may be acquired through the symptomatic wrist. If the patient's palm is rotated 90[infinity] to face the patient's head, direct coronal scans of the symptomatic wrist may be acquired. Last, in the trauma setting, CT images may be acquired in one additional plane, specially designed to assess the scaphoid. Images obtained in the sagittal oblique plane are taken along the long axis of the scaphoid. The scan is performed with the ulnarly-deviated wrist prone against the table.

In current clinical practice, wrist CT is most often requested in assessing nonunion of fractures, particularly a scaphoid waist fracture (Fig. 16). Less frequently, CT is utilized to better define a previously detected fracture or to assess the distal radioulnar joint for subluxation or dislocation (Fig. 17).[18]

Figure 16. Sagittal CT image of the right wrist demonstrates sclerosis at the margins of the proximal and distal pole scaphoid fracture fragments. No bony bridging is present at the scaphoid waist fracture site consistent with a nonunion.
Figure 17. Transaxial CT image of both wrists performed at the level of the distal radioulnar joint (DRUJ). On the left there is diastasis of the DRUJ to almost 2cms.

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