High-concentration iodinated contrast media for T1-weighted direct magnetic resonance arthrography

To quantify in vitro the T1-weighted (T1W) expression of iodinated contrast media (CM), and to compare the in vivo performances of iodinated CM and gadolinium-based CM for T1W direct magnetic resonance imaging (MRI) arthrography.

An in vitro study on a 1.5 T MRI system was performed using Gd-DOTA, a mixture of iopromide and Gd-DOTA, and iopromide alone. The fat-suppressed (FS) T1W signal intensities were measured and analysed. In an in vivo study, 15 normal rabbits were used to compare the expression of iopromide (370 mg iodine/ml), and the mixture of iopromide and diluted Gd-DOTA. In nine of the 15 rabbits, extra-articular administrations of CM were performed to mimic the situation of CM leak. The rabbits were scanned on a 1.5 T MRI system, and the FS T1W sequence and an axial iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) T1W sequence were acquired. Signal intensities were measured and signal-to-noise ratios (SNR) were analysed.

In the in vitro study, a higher SNR was noted in a higher concentration of iopromide, and the highest SNR of iopromide was 45.9% of that of Gd-DOTA. In the in vivo study, the iopromide and the mixture were well identified in all rabbits. The SNRs of the intra-articular and extra-articular iopromide and the mixture were significantly higher than the SNR of the muscles in the FS T1W images (all, p<0.01) and the IDEAL images (all, p<0.01).

A high-concentration iodinated CM can provide good imaging quality for T1W direct MRI arthrography, and may be an alternative option in certain clinical situations.