Use of routine clinical multimodality imaging in a rabbit model of osteoarthritis - part I

Objective: To evaluate in vivo the evolution of osteoarthritis (OA) lesions temporally in a rabbit model of CA with clinically available imaging modalities: computed radiography (CR), helical single-slice computed tomography (CT), and 1.5 tesla (T) magnetic resonance imaging (MRI). Methods: Imaging was performed on knees of anesthetized rabbits [10 anterior cruciate ligament transection (ACLT) and contralateral sham joints and six control rabbits] at baseline and at intervals up to 12 weeks post-surgery. Osteophytosis, subchondral bone sclerosis, bone marrow lesions (BMLs), femoropatellar effusion and articular cartilage were assessed. Results: CT had the highest sensitivity (90%) and specificity (91%) to detect osteophytes. A significant increase in total joint osteophyte score occurred at all time-points post-operatively in the ACLT group alone. BMLs were identified and occurred most commonly in the lateral femoral condyle of the ACLT joints and were not identified in the tibia. A significant increase in joint effusion was present in the ACLT joints until 8 weeks after surgery. Bone sclerosis or cartilage defects were not reliably assessed with the selected imaging modalities. Conclusion: Combined, clinically available CT and 1.5 T MRI allowed the assessment of most of the characteristic lesions of OA and at early time-points in the development of the disease. However, the selected 1.5 T MRI sequences and acquisition times did not permit the detection of cartilage lesions in this rabbit OA model. (C) 2008 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.