Evaluation of Femoral Perfusion in a Rabbit Osteonecrosis Model with T2*-weighteddynamic Mri

Introduction: Magnetic resonance imaging (MRI) is highly sensitive and considered less invasive than other modalities to early diagnosis of non-traumatic osteonecrosis (ON). However, it is generally based on detection of reparative reactions to ON and it is quite difficult to directly detect bone ischemia, which corresponds to initial Stage 0 of the ARCO (Association Research Circulation Osseous) international classification system. Femoral perfusion has been evaluated using T1weighted dynamic MRI with gadolinium (Gd) contrast agent, so far. However, this method may not always be appropriate for evaluating femoral perfusion in point of a mechanism of contrast enhancement and the pharmacokinetics of Gd contrast agent. On the other hand, T2*weighted dynamic MRI utilizes a transient decrease of signal intensity during the first pass of Gd contrast agent and is used for evaluating brain perfusion mainly. We applied T2*-weighted dynamic MRI to a rabbit non-traumatic ON model and investigated the possibility of evaluating femoral perfusion and predicting ON occurrence.