Imaging Time-Intensity Curve Shape Purpose : Methods : Results : Conclusion :

Abstract

Purpose: To analyze the distribution of different shapes of time- intensity curves (TICs) in synovial tissue of patients with rheumatoid arthritis (RA) and to compare relative num- bers of TIC shapes between patients with RA and healthy control subjects. Materials and Methods: This prospective study was approved by the institutional review board; patients and control subjects gave written informed consent. Dynamic contrast material–enhanced magnetic resonance (MR) imaging of the knee joint in five patients with early RA and in five control subjects was performed. Parametric maps showing seven TIC shape types were created. Spatial information of the synovial TIC shape distribution pattern and relative number of TIC shapes were calculated on a three-dimensional region of interest. Relative TIC shape numbers were compared by using a nonparametric Mann-Whitney U test. Results: Synovial enhancement in patients with RA consisted of type 2 TIC shapes (slow enhancement) with heteroge- neous zones of types 3 (fast enhancement followed by plateau phase), 4 (fast enhancement followed by early washout phase), and 5 (fast enhancement followed by slow enhancement increase) TIC shapes, compared with almost only type 2 TIC shapes in control subjects. The heteroge- neous zones were seen in the lateral and medial knee compartments and around the cruciate ligaments. A signif- icantly higher relative number of type 4 TIC shapes was observed in the patient group compared with the control group (16.5% vs 6.9%, P  .008).