"Quantitative MRI Methods to Detect Early-Stage Ischemic Injury to the Femoral Head"

Osteonecrosis of the femoral head (ONFH) is a serious hip disorder that can lead to osteoarthritis and need for total joint replacement at a young age. ONFH has many different etiologies and affects both children and adults, but all causes involve ischemic injury to the bone marrow and bone of the femoral head that can lead to its mechanical weakening and collapse. Treatment of ONFH is focused on preserving the sphericity of the femoral head to prevent its collapse and onset of osteoarthritis. However, current hip preservation procedures often fail to prevent disease progression, and ONFH can be difficult to diagnose in the early stages of the disease when treatment would be most effective. In this talk, I will give an overview of my lab's efforts to validate quantitative MRI techniques, such as T2 and T1rho relaxation time mapping and diffusion imaging, to detect early-stage ischemic injury to the femoral head. Particular emphasis will be placed on results from studies of a piglet model of Legg-Calve-Perthes disease, a juvenile form of ONFH. These efforts aim to establish new imaging techniques to better diagnose ONFH, predict clinical outcome, and monitor treatment response.

Dr. Johnson received his PhD in Biomedical Engineering at the Mayo Clinic, where he worked on techniques for high-resolution, real-time MRI of the peripheral arteries. He then did his postdoctoral training in the laboratory of Vince Magnotta at the University of Iowa, where he focused on functional and quantitative MRI of the brain, particularly with application to bipolar disorder. Dr. Johnson then joined the University of Minnesota's Center for Magnetic Resonance Research to focus on MRI of developmental musculoskeletal disorders. In his current position as an assistant professor in the Department of Veterinary Clinical Sciences, University of Minnesota, Dr. Johnson is working to develop, validate, and translate quantitative MRI of ischemic and degenerative joint disorders to inform clinical management and treatment of patients with the goal of preventing long-term disability and chronic pain.