Wouter Stomp MD, Presenter: Speaker, General Electric Company

Johan L. Bloem MD, PhD, Abstract Co-Author: Nothing to Disclose

Tom WJ Huizinga, Abstract Co-Author: Nothing to Disclose

Annette Van Der Helm-Van Mil, Abstract Co-Author: Nothing to Disclose

Monique Reijnierse MD, Abstract Co-Author: Nothing to Disclose

In rheumatoid arthritis, identifying the exact demarcation of erosions on MR images can be difficult because the cortical defect might be obliterated by either synovium or bone marrow edema.. Opposed-phase MR imaging might enhance the visibility of this transition by visualizing it as a clear black line due to the presence of both water and fat protons within the same voxel. The purpose of this study was to determine whether opposed phase gradient-echo imaging improves visualization of erosions when compared to regular T1w TSE sequences.

Unilateral wrist and MCP joints of 14 early arthritis patients were imaged on a 1.5T extremity MRI. T1w TSE and opposed phase T1w gradient-echo sequences were obtained in the coronal plane, both before and after gadolinium contrast administration. T2w TSE images were also obtained and were available to support scoring for both image sets. Images were assessed for image quality on a 0-5 scale and scored according to the OMERACT RAMRIS score for erosions in consensus by two observers blinded to clinical data. A reference score was established using all available images together.

Scanning time was 0:43 for the opposed phase sequence and 3:30 for the TSE sequence. Overall image quality, absence of movement artifacts and sharpness were significantly better using opposed phase images than T1w TSE images. Homogeneity, Signal-to-noise ratio, RAMRIS erosion scores and rater confidence did not differ between sequences. There was a trend towards higher sensitivity of opposed phase images for detection of erosions (85.6%, 95%CI 76.6-91.6% vs 68.0%, 95%CI 57.7-76.9%). Specificity, positive predictive value and negative predictive value were similar between the sequences and all >85%.

Our results demonstrate the feasibility of using a fast out-of-phase T1w spoiled-gradient echo sequence to assess erosions according to OMERACT RAMRIS score. It decreases imaging time while providing better image quality and might increase sensitivity for small erosions.

Shorter scanning time of the opposed phase sequence reduces movement artifacts and patient discomfort, and better delineation of the bone-tissue interface may improve reliability of erosion detection.

Stomp, W, Bloem, J, Huizinga, T, Van Der Helm-Van Mil, A, Reijnierse, M, Opposed-phase Gradient Echo MR Imaging Improves Image Quality and Visualization of Erosions in Arthritis.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013785.html