Delayed contrast enhanced MRI of meniscus with ionic and non-ionic agents.

PURPOSE: To evaluate the potential difference in post-contrast T(1) relaxation time of the meniscus (T(1Gd)) between osteoarthritic patients (OA) and healthy subjects (HS), and to verify if charge density has any influence on meniscal T(1Gd).

MATERIALS AND METHODS: We performed a retrospective analysis of meniscal T(1) relaxation time on data previously acquired for studying articular cartilage with both ionic and non-ionic contrast media. MR imaging was performed in 10 OA and 8 HS at 120 min following administration of double-dose ionic Gd-DTPA(2-) on one day and non-ionic Gd-DTPA-BMA on a different day. A three-dimensional Look-Locker sequence with echo time of 2 ms was used for data acquisition to allow T(1) mapping of the meniscus.

RESULTS: Compared with HS, significantly lower meniscal T(1Gd) was observed in OA with either ionic Gd-DTPA(2-) (P < 0.01) or non-ionic Gd-DTPA-BMA (P < 0.001) contrast agent. There was a correlation between meniscal T(1) (Gd-DTPA(2-)) versus T(1) (Gd-DTPA-BMA). Meniscal T(1) (Gd-DTPA-BMA) showed a larger difference and smaller overlap between OA and HS. No significant differences in either pre-contrast T(1) or post-contrast T(1Gd) were observed between inner and outer zones of the meniscus with either agent.

CONCLUSION: Significant differences in meniscal T(1Gd) between OA and HS were observed with both ionic and non-ionic contrast agents, suggesting that charge density is not responsible for the observed differences.