Abstract: To explore the T2 value of patellar cartilage grouped respectively by radiographic stage of patellofemoral OA and by body mass index(BMI). Methods72 subjects were grouped based on KL into the normal, mild OA, and severe OA groups and on BMI into the normal, overweight, and obese groups. They were scanned using four echoes′ spineecho, and the T2 value of patellar cartilage was measured. ResultsThe mean T2 value was 37.9±4.9 ms, 48.5 ±7.5 ms, and 51.7±5.2 ms in the normal group, mild OA group, and severe OA group. No significance was found between the mild and severe OA groups(P＞0.05). BMI had a significant effect on T2 value (P＜0.001, and P＜0.05 among the three groups). ConclusionResults indicate that the T2 values are not sensitive to changes according to radiographic stages of OA. T2 values with BMI signify structural changes of patellar cartilage, and BMI may be a potential factor for an increase of T2 values.

Key words: Osteoarthritis, Patellar cartilage, Knee joint, T2 value, Magnetic resonance imaging, Xray,diagnostic