Magnetic Resonance Imaging Evaluation in Legg-Calve-Perthes disease.

Magnetic Resonance Imaging (MRI) was performed in eighteen patients with unilateral Legg-Calve-Perthes disease (LCPD). In the initial stage, MRI demonstrated necrotic regions of the epiphysis as a low intensity area on T1 and T2-weighted images more clearly than on the plane X-ray films. The earlinest images of this initial stage showed the low intensity crescent zone at the subchondral lesion and this area extended throughout the epiphysis in the group 4 LCPD and within the anterior three-quarters in the group 3.In the fragmentation stage, bright areas gradually apeared in the epiphysis on T2-weighted images but no remarkable changes in the intensities of the head were seen on T1-weighted images.In the reparation stage, the brightness of the epiphysis tended to slightly weaken on T2-weighted images. On T1-weighted images recovery of the brightness of the epiphysis was prolonged representing delay in the maturation of the epiphysis. The area in the head showing high intensity on T2-weighted images and low on T1-weighted images was thought to be weak for weight bearing. The apparatus for LCPD should not be discarded until the high intensity area was seen not only on T2 images but also on T1 images in the femoral epiphysis.