INTRAARTICULAR DIFFUSION OF GD-DOTA AFTER INTRAVENOUS-INJECTION IN THE KNEE - MR-IMAGING EVALUATION

Intraarticular concentration of gadolinium tetraazacyclododecanetetraa cetic acid (DOTA) after intravenous injection and the diagnostic contr ibution of the subsequent arthrographic effect were assessed for menis cal lesions in the knee. Kinetics were studied in three healthy volunt eers. Passage of contrast material into the synovial fluid of the join t was evaluated in 53 knees by measuring the signal intensity on T1-we ighted images before, immediately after, and 1 hour after injection. S ynovial fluid enhancement was 1.46-fold greater than the unenhanced va lue after 10 minutes, plateaued after 30 minutes, and was 1.95-fold gr eater after 1 hour. In articular fluid samples from four patients 1 ho ur after intravenous injection, the average intraarticular concentrati on was 141 mumol +/- 47 (1 standard deviation) at atomic absorption sp ectrophotometry. Knee mobilization improved the passage of contrast ma terial into the synovial fluid by approximately 120% at 10 minutes and 25% at 1 hour. In eight of 39 tears, unenhanced standard sequences we re equivocal. In seven of these uncertain cases, delayed contrast-enha nced images permitted adequate interpretation. Intraarticular concentr ation of Gd-DOTA produces a sufficient arthrographic effect for menisc us evaluation.