Abstract:  MRI Intravenous contrast enhancement of inflammatory synovium has been studied at two different doses to determine to what extent enhancement is does dependant. 19 patients with clinically active rheumatoid arthritis involving a knee were scanned twice, one week apart, using 0.1 mmol/kg of gadoteridol (Prohance) on the first occasion and 0.3 mmol/kg on the second.