Imaging of the Wrist and Hand

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

Disclosures

Medscape General Medicine. 1999;1(1) 

In This Article

Bone Scintigraphy

Bone scintigraphy relies on the detection of radiotracer activity by gamma camera following intravenous injection of a radioactive agent. Images obtained during the injection of radiotracer are referred to as arterial phase or flow images. Additional images may be obtained within 15 minutes or at 2 to 4 hours following the injection of radiotracer. These are referred to as blood pool and delayed or static images, respectively. Flow and blood pool images demonstrate radiotracer activity within the soft tissues, whereas delayed images, obtained following the clearance of the majority of soft tissue radiotracer activity, demonstrate radiotracer activity localized to bone (Fig. 22).

Figure 22. (a) Posteroanterior radiograph of the right hand is normal. Three-phase bone scintigraphy: (b) the arterial and (c) blood pool phases demonstrate increased radiotracer activity to the entire distal right extremity; (d) the delayed phase shows localized increased radiotracer activity surrounding the wrist, metacarpophalangeal, and interphalangeal joints. This pattern of uptake is pathognomonic for reflex sympathetic dystrophy.

Bone scintigraphy (static phase images alone) is ideal as a screening tool for bone pathology because of its high sensitivity. However, in centers where MRI is available, MRI is preferable for fracture detection, primarily because of the additional specificity that it provides. In centers where MRI is not readily available, bone scintigraphy remains quite useful. A positive bone scan suggests the need for further investigation, usually with CT to provide fine bone detail and fracture recognition.[30]

A negative bone scan indicates that patient pathology is not within the bone. Thus no further bone imaging is warranted.

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