technetium-tc-99m-pyrophosphate and Synovitis

Topics: Adult; Diagnosis, Differential; Hemarthrosis; Hemophilia A; Humans; Joints; Osteoarthritis; Radionuclide Imaging; Recurrence; Synovitis; Technetium Tc 99m Pyrophosphate

We examined the time course of the development of hemorrhagic synovitis in response to repeated autologous blood injections into knee joints in mature dogs and the possible usefulness of joint imaging with technetium-99m pyrophosphate (Tc99m-PYP) in monitoring the early response of synovium to blood. Experimental hemarthrosis was induced in dogs by twice weekly injection of autologous blood into the knee joints. Sequential examination of the synovium at monthly intervals over a period of 12 weeks revealed early inflammatory cell infiltration and capillary neovascularization with eventual replacement of the normal fatty synovium by dense fibrous tissue. Serial Tc99m-PYP joint images demonstrated a progressive increase in isotope accumulation in the knees during the course of the study. Further isotope accumulation was observed after CO2 laser synovectomy. During the 24-week course of the entire study, no changes in joint cartilage or bone were observed by gross inspection or radiologic and light-microscopic examination. The findings indicate that the progressive proliferative, inflammatory, fibrotic changes in joint synovium associated with experimental hemarthrosis in dogs may be noninvasively and semiquantitatively assessed with the use of Tc99m-PYP scintigraphy. Evidence is also presented that the intensity of Tc99m-PYP joint accumulation (immediate static images) may not readily reflect synovial vascularity or synovial tissue mass.

Topics: Animals; Diphosphates; Dogs; Hemarthrosis; Knee Joint; Radionuclide Imaging; Synovitis; Technetium; Technetium Tc 99m Pyrophosphate

Radionuclide joint imaging with the technetium-99m-labeled phosphates is a sensitive technique for the detection of inflammatory articular disease, although it is nonspecific as to the cause of the increased uptake and offers poor resolution in comparison to conventional radiography. There does not appear to be any place for the routine use of joint imaging of the peripheral joints, as there is little evidence that it benefits patient management. Scintigraphy is of benefit in the detection of osteomyelitis, Legg-Perthes' disease, and osteonecrosis, where changes may antedate roentgenologic abnormalities. Technetium-99m-phosphates may have an increasing role in the evaluation of knee and hip prosthetic joint loosening and infection, especially regarding the femoral components. Scintigraphy may be useful in excluding synovitis and allaying concern in selected patients with chronic articular pain in whom a conventional diagnostic evaluation is unrewarding. Attempts have been made to use radionuclide joint imaging to quantitate the degree of synovitis present in individual joints, particularly the sacroiliac joints. To date, reliable methods that distinguish normal from abnormal joints have not been established, although this remains an area of potential usefulness and active research. Scintigraphy with 99mTc-phosphates is useful in the detection of spinal fracture and pseudoarthrosis in individuals with ankylosing spondylitis.

Topics: Adult; Arthritis; Bone Neoplasms; Child; Diphosphates; Diphosphonates; Female; Gallium Radioisotopes; Humans; Joint Diseases; Legg-Calve-Perthes Disease; Male; Middle Aged; Osteoarthritis; Osteomyelitis; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Spondylitis, Ankylosing; Synovitis; Technetium; Technetium Compounds; Technetium Tc 99m Medronate; Technetium Tc 99m Pyrophosphate