Avascular necrosis of the femoral head following hysteroscopic myomectomy: Evaluation of bone perfusion using dynamic contrast-enhanced MRI and intravoxel incoherent motion.

Avascular necrosis of the femoral head (ANFH) results from compromised vascular supply, leading to osteonecrosis and progressive structural weakening that may culminate in articular collapse and functional disability. We report a case of a 33-year-old woman who developed avascular necrosis of the right femoral head six weeks after a three-hour hysteroscopic myomectomy. Initial non-contrast magnetic resonance imaging (MRI) demonstrated early-stage osteonecrosis. Two weeks later, a sudden increase in hip pain raised concern for femoral head collapse, prompting a non-contrast computed tomography (CT) scan. CT revealed intraosseous gas within the necrotic region, with subtle evidence of articular collapse at the superior aspect of the femoral head. A contrast-enhanced MRI was subsequently performed to exclude a possible superimposed anaerobic infection and included dynamic contrast-enhanced (DCE-MRI) and intravoxel incoherent motion (IVIM) sequences. Functional MRI techniques allowed in vivo evaluation of perfusion and microvascular diffusion within the affected femoral head, providing valuable insight into areas likely corresponding to necrotic bone, reparative tissue, and preserved marrow. Multimodal imaging integrating morphological and functional findings enabled detailed interpretation of distinct zones representing different stages or characteristics of tissue response to ischemic injury. This case report highlights the potential of functional MRI techniques to enhance understanding of perfusion alterations in avascular necrosis of the femoral head.