Sheen-Woo Lee MD, Presenter: Nothing to Disclose

David Leaffer, Abstract Co-Author: Nothing to Disclose

Joan Greve, Abstract Co-Author: Nothing to Disclose

Lance Lollini DVM, Abstract Co-Author: Nothing to Disclose

Anthony Manning PHD, Abstract Co-Author: Nothing to Disclose

Garry Evan Gold MD, Abstract Co-Author: Nothing to Disclose

Sandip Biswal MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To establish sensitive and reproducible in-vivo imaging methods to detect early changes in a murine model of RA.

Adjuvant-induced arthritis (AIA) was created by injecting complete Freund's adjuvant into the tail. Right hindpaws of living rats were evaluated with 4.7T microMRI. Post-mortem, formalin-fixed paw specimens were evaluated with xerography, 45um-resolution microCT and histologic processing. Animal paws were imaged on post-induction (PI) days 0, 1, 3, 5, 6, 7, 8, 9 and 12 (total n=29). MRI parameters were: sagittal T1-weighted SE (TR/TE/resolution 600/14.1msec/0.137x0.137x0.68mm) and inversion recovery (TR/TE/TI/resolution 3300/14.8/220msec/0.273x0.273x0.68mm). Three radiologists independently scored the MR images for the presence joint effusion, soft tissue swelling, bone marrow signal changes and bone erosions. Bone mineral density measurements (BMD) and the presence of bony erosions or proliferation were obtained from microCT images. Histology was analyzed by a pathologist.

The initial appearance of joint effusion, soft tissue swelling, bone marrow signal changes and bone erosions on MRI were seen on PI day 1, 5, 5, and 8, respectively. On microCT, a significant decrease in BMD was found especially around the growth plate of the distal tibia by PI day 7 (p = 0.018). Osteolysis on microCT was seen as early as 6-8 days PI. Of note, xerography was not able to detect any changes in any of the animals studied. Histologic findings of cellular infiltration in the bone marrow and related bone destruction correlated with the findings from the MRI and CT (r2>0.8). Progression of microMR and microCT imaging findings also corroborated the extent of histologic findings.

Early histological changes seen in an animal model of RA can be detected with microMRI and microCT. Progression of MRI findings, such as increasing marrow signal change, joint effusion, and soft tissue swelling, and progression of microCT findings, such as decreasing BMD and increasing bone destruction, correspond to increasing inflammatory cellular infiltrate, pannus and osteoclastic osteolysis in affected tissues.

Lee, S, Leaffer, D, Greve, J, Lollini, L, Manning, A, Gold, G, Biswal, S, et al, , Early Histological Changes Seen in a Murine Model of Rheumatoid Arthritis (RA) Can Be Detected with Micro-Computed Tomography (microCT) and Micro-Magnetic Resonance Imaging (microMRI).  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4419479.html