Evaluation of femoral perfusion in a non-traumatic rabbit osteonecrosis model with T2*-weighted dynamic MR1

We evaluated femoral perfusion in a non-traumatic rabbit serum sickness osteonecrosis (ON) model, using serial repetitive T2*-weighted (T2*W) dynamic magnetic resonance imaging (MRI) and investigated prediction of ON occurrence in early stages, comparing T2*W dynamic MRI with non-enhanced (T2-, T1- and fat suppression T1-weighted) and contrast-enhanced MRI. Early microcirculatory injury or necrotic lesion was detected in 0% of femora (extravasation, 0/6) at 72 It, 33% (necrotic, 4/12) at I week and 100% (necrotic, 14/14) at 3 weeks using non-enhanced MRI, and in 67% of femora (extravasation, 4/6) at 72 h, 58% (necrotic, 7/12) at I week and 100% (necrotic, 14/14) at 3 weeks using contrast-enhanced MRI. In contrast, microcirculatory injury or necrotic lesion was detected in 83% of femora (extravasation, 5/6) at 72 h, 92% (necrotic, 11/12) at I week and 100% (necrotic, 14/14) at 3 weeks using T2*W dynamic MRI as no transient decrease or less marked transient decrease in signal intensity of regions of interest (ROIs), compared to normal femora, which showed a clear transient decrease in signal intensity of ROIs. These results indicate that T2*W dynamic MRI with optimal imaging parameters and a dose of contrast agent is the most sensitive of these three MRI methods and may be clinically useful for evaluating femoral perfusion in artery phase and predicting ON occurrence. (C) 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.