変形性膝関節症のMRI画像で見られる大腿骨輪郭不整の経年的変化 : Irregularity Index Systemを用いて計測したOsteoarthritis Initiative (OAI)のデータを用いた平均14か月のフォローアップ

摘要

Osteoarthritis of the knee joint (KOA) is an important problem to be solved in aged society. Objective assessment of disease progression is mandatory for establishing adequate treatment system. Radiographic examination is a standard method but it is too rough to detect subtle changes occur in limited period. Contrary to this, magnetic resonance imaging (MRI) is expected to work as biomarker as it appears to be keen enough to capture subtle changes. Several MRI-based assessment systems have been developed to assess the status of KOA but they are too complicated and time consuming. Originally developed system, the Irregularity Index System (I-I System) is one of those but the simplest method because it is composed of only one item; i.e., the contour of the femoral condyle. Cross-sectional study revealed good correlation between irregularity of the contour and clinical severity but longitudinal changes are yet to be solved. In this paper longitudinal change of irregularity was determined using publicly available MRI data base concerning KOA. As a result, I-I System could detect changes over average of 14 months and it related to deterioration of clinical knee score.