To study the frequency of technetium-99m-positive ciprofloxacin scans (Infecton scintigraphy) thought to be specific for bacterial DNA in patients with arthritis and to assess the clinical relevance of positive scans.
Four groups of adults with arthritis were studied. Group 1: 53 patients with inflammatory arthritis, 36 with spondylarthropathy (SpA) and 17 with rheumatoid arthritis (RA); group 2: five patients with crystal arthropathy; group 3: those patients with osteoarthritis (OA) of the knee, wrist or spine; and group 4: 28 patients who had no arthritis but were being investigated for renal infection. Patients were injected with 10 mCi 99Tcm-ciprofloxacin with isotope uptake analysis at 4 h. Clinically swollen joints were assessed by a rheumatologist and the positive scans assessed by a physician in nuclear medicine.
Increased Infecton uptake was noted in inflamed joints independent of the pathology. It was seen in 10 of 17 patients with SpA, 12 of 17 with RA, all five with crystal arthropathy, eight with knee OA, two with wrist OA, none with spinal OA and none in uninflamed joints. A close correlation between clinically swollen joints and articular Infecton uptake was noted (P = 0.0003), with the uptake being in the distribution of the synovial perimeter. Additional uptake was noted in the abdomen (n = 9) and pulmonary region (n = 2) of SpA patients.
The Infecton scan is not specific for infection but may be a reliable procedure for identifying the presence and distribution of the inflammation within joints. It has the potential for monitoring the response of inflamed joints to treatment.