Temporal behavior of intraarticular gadolinium

Purpose: As imaging delays during MR arthrography can result in suboptimal studies and potential pitfalls in diagnosis, we sought to evaluate the temp oral behavior of intraarticular Gd-DTPA. Method: We prospectively studied four shoulders, four knees, and four hips. Two of each group received either an intraarticular injection of 3 mmol/L Gd-DTPA and iodinated contrast medium or 2 mmol/L Gd-DTPA and 0.9% saline. We measured contrast-to-noise ratio (CNR) and joint distention on serial T1 -weighted sequences. Retrospectively, we measured CNR and imaging delays in 31 MR arthrography patients (20 shoulders, 7 knees, and 4 hips). Results: In the shoulder, maximal CNR and joint distention occurred at 15 m in. CNR decreased 53% by 1 h. In the knee, maximal distention occurred at 1 h, whereas CNR peaked at 2.75 h and then declined 20 and 86% by 3.5 and 6. 25 h, respectively. In the hip, peak CNR and distention occurred at 0.5 h. CNR declined 53% by 2 h. Both contrast mixtures yielded similar results. Conclusion: MR arthrography may tolerate imaging delays of 1 h for the shou lder, 2 It for the hip, and 3.5 It for the knee.