Radionuclide joint imaging in the seronegative spondyloarthropathies

Radionuclide joint imaging (RJI) of the peripheral and axial skeleton is a recent advance in the detection of early articular inflammation and has proven useful in establishing the extent and pattern of this involvement. The bone-seeking agents--the radiophosphates--are the radiopharmaceuticals presently favored for RJI in adults. They are more sensitive than the clinical examination in detecting inflammatory joint disease in all peripheral joints with the exception of the shoulders, elbows and knees. Radiophosphate may also be used to evaluate the axial skeletion for inflammatory involvement. The sacroiliac joints may be evaluated by a new technique, quantitative saroiliac scintigraphy (QSS). Studies to date have demonstrated that QSS is most sensitive in early sacroiliitis, a time when conventional radiography is normal or shows equivocal abnormalities. While extremely sensitive as a screening procedure for inflammatory articular disease, RJI is nonspecific diagnostically. Radiophosphate uptake by bone occurs in metabolic bone disease, osteoarthritis, trauma and juxta-articular bony abnormalities such as osteomyelitis and bone infraction. The results obtained by radionuclide joint imaging must be supplemented by the clinical findings and conventional investigations to establish a specific diagnosis.