MR Imaging of Proximal Femur: Age-related Changes

ABSTRACT

PURPOSE: The purpose of this study is to illustrate MR patterns of signal intensity of proximal femur in normal subjects according to the age distribution. METHOD AND MATERIAL: Tl-weighted MR images of the proximal femur in 125 subjects, aged 13 days to 25 years, were retrospectively analyzed. Age distribution was classified to 4 groups;below 4 months, 5 months to 4 years, 5 years to 14 years, and 15 years to 25 years. RESULTS: By the age of 4 months, the non-ossified femoral epiphysis was seen as intermediate-signal-intensity cartilage. At 5 months-4 years, the ossified fernoral capital epiphysis was seen within intermediate-signal-intensity cartilage and appeared as decreased or increased signal-intensity red or yellow marrow surrounded by a rim of low-signal-intensity cortical bone. At 5-14 years, the ossified femoral capital and greater trochanteric epiphysis were seen within the intermediate-signal-intensity cartilage and appeared as decreased or increased signal-intensity red or yellow marrow. At 15-25 years, the proximal metaphyseal marrow showed increased signal intensity. Four patterns of the metaphyseal marrow were recognized by Ricci et al. The frequency of pattern la progressively decreased with age. Pattern 2 and 3 were visible in the 15-25 years age group. CONCLUSION: An understanding of the spectrum of normal age-related change of the proximal femoral cartilage and marrow patterns serves as the foundation for interpretation of proximal femur pathologies.