GLYCOSAMINOGLYCAN IN ARTICULAR-CARTILAGE - IN-VIVO ASSESSMENT WITH DELAYED GD(DTPA)(2-)-ENHANCED MR-IMAGING

PURPOSE: To investigate the feasibility of applying magnetic resonance (MR) imaging with use of an anionic compound, Gd(DTPA)(2-) (gadoliniu m diethylenetriaminepentaacetic acid), for measuring glycosaminoglycan concentration in human cartilage in clinical studies. MATERIALS AND M ETHODS: Penetration of Gd(DTPA)(2-) into cartilage was monitored throu gh sequential T1-calculated images obtained after intraarticular (n = 2) or intravenous (n = 2) injection. T1-weighted and T1-calculated ima ge series were then obtained in seven volunteers (nine knees) after pe netration of Gd(DTPA)(2-) into cartilage. If T1 was heterogeneous on G d(DTPA)(2-)-enhanced images, images were also obtained after penetrati on of the cartilage with the nonionic contrast agent, gadoteridol. RES ULTS: Gd(DTPA)(2-) penetrated cartilage from the articular surface aft er intraarticular injection and from both the articular surface and th e subchondral bone after intravenous injection. The latter resulted in shorter overall penetration time. T1 values on Gd(DTPA)(2-)-enhanced images were homogeneous in four knees, but in five knees T1 difference s of up to 30% were observed. These T1 differences were not seen in th e presence of gadoteridol. These variations in T1 reflected about 50% variations in glycosaminoglycan. CONCLUSION: The data suggest that Gd( DTPA)(2-)-enhanced MR imaging has potential for monitoring glycosamino glycan content of cartilage in vivo.