Intraarticular diffusion of Gd-DOTA after intravenous injection in the knee: MR imaging evaluation.

Intraarticular concentration of gadolinium tetraazacyclododecanetetraacetic acid (DOTA) after intravenous injection and the diagnostic contribution of the subsequent arthrographic effect were assessed for meniscal lesions in the knee. Kinetics were studied in three healthy volunteers. Passage of contrast material into the synovial fluid of the joint was evaluated in 53 knees by measuring the signal intensity on T1-weighted images before, immediately after, and 1 hour after injection. Synovial fluid enhancement was 1.46-fold greater than the unenhanced value after 10 minutes, plateaued after 30 minutes, and was 1.95-fold greater after 1 hour. In articular fluid samples from four patients 1 hour after intravenous injection, the average intraarticular concentration was 141 mumol +/- 47 (1 standard deviation) at atomic absorption spectrophotometry. Knee mobilization improved the passage of contrast material into the synovial fluid by approximately 120% at 10 minutes and 25% at 1 hour. In eight of 39 tears, unenhanced standard sequences were equivocal. In seven of these uncertain cases, delayed contrast-enhanced images permitted adequate interpretation. Intraarticular concentration of Gd-DOTA produces a sufficient arthrographic effect for meniscus evaluation.