Using MRI and PET to Detect Early Knee Osteoarthritis

Researchers from Stanford University have developed the first protocol using magnetic resonance imaging (MRI) for detecting early stage knee osteoarthritis (OA) in all joint tissues. Their findings were recently published in Osteoarthritis and Cartilage. 

Traditionally, joint tissues are examined separately, and MRI can only assist in monitoring changes in the subchondral bone when the disease has progressed substantially. The group of researchers led by Feliks Kogan, PhD, saw the need to create a technique that could non-invasively assess changes in bone remodeling and adjacent tissues.

The researchers studied patients with unilateral injured anterior cruciate ligament (ACL), which is commonly at risk for OA. Through using positron emission tomography (PET) and MRI, they fully examined the bone and cartilage’s early metabolic and cellular changes. With PET, the (18) F-Sodium fluoride traced the bone osteoblast activity. The MRI allowed the researchers to quantify early OA changes in cartilage. They found that the injured areas showed “increased (18)F-NaF PET uptake in subchondral bone compared to their unaffected contralateral knees.”

“…our novel approach allows for simultaneous, and quantitative assessment of spatial relationships between multiple early markers of disease in subchondral bone and articular cartilage,” Kogan told Orthopedics This Week. “We used this strength to study spatial relationships between increased subchondral bone metabolism and adjacent MRI markers of cartilage matrix changes.”