Diffusion-weighted MRI Reveals Epiphyseal and Metaphyseal Abnormalities in Legg-Calvé-Perthes Disease: A Pilot Study

Abstract

Background Legg-Calvé-Perthes disease (LCP) is thought to be associated with ischemic events in the femoral head. However, the types and patterns of reperfusion after these ischemic events are unclear. Purposes We therefore determined whether (1) there would be any age-related diffusion changes; (2) diffusionweighted MR imaging would reveal ischemic damage; and (3) diffusion changes are correlated with prognostic MR findings in patients with LCP. Methods We prospectively performed conventional, perfusion, and diffusion-weighted MR imaging studies in 17 children with unilateral LCP. We then measured the apparent diffusion coefficient (ADC) values in the epiphysis and the metaphysis, and compared them with those of the contralateral normal side. Based on perfusion MR imaging, we assessed reperfusion to the epiphysis as either periphyseal or transphyseal. We studied T2-signal intensity changes in the metaphysis and the presence of focal physeal irregularity. We correlated diffusion changes with reperfusion to the epiphysis, T2-signal intensity change, and focal physeal irregularity. Results Normal diffusion decreased with age. In LCP hips, epiphyseal diffusion increased early and remained elevated through the healing stage. Six of the 17 patients who had a metaphyseal ADC greater than 50% over the Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. 123Clin Orthop Relat Res (2011) 469:2881-2888 DOI 10.1007/s11999-011-1931 normal side had 13 times greater odds of having an association with transphyseal reperfusion to the epiphysis. The increase of metaphyseal ADC also was associated with an increased T2-signal intensity in the metaphysis and presence of focal physeal irregularity. Conclusions Diffusion-weighted MR imaging can be used as a complimentary modality to evaluate ischemic tissue damage with a potential prognostic value in patients with LCP.

Magnetic resonance perfusion and diffusion imaging characteristics of transient bone marrow edema, avascular necrosis and subchondral insufficiency fractures of the proximal femur

“…As necrotic tissue would indicate restricted diffusion, this result is unexpected. However, increased diffusion in necrotic bone was also demonstrated in several studies, which applied DWI to evaluate Patients with femoral head avascular osteonecrosis [18,22] and Legg-Calvé-Perthes disease [17,23]. The increase of diffusion was explained by a breakdown of the matrix components and more active water diffusion in bone marrow.…”

Magnetic resonance imaging in children with sickle cell disease—detecting alterations in the apparent diffusion coefficient in hips with avascular necrosis

“…Hip ischemia in a piglet model of avascular necrosis (AVN) demonstrates initial restriction in diffusion with reduced blood flow. With increasing duration of ischemia, the diffusion increases rapidly and remains elevated [3][4][5] and in Legg-Calvé-Perthes disease, preliminary data indicate that epiphyseal diffusion varies with the stage of disease [5,6].…”

The Pelvis and Hip: Acquired Disorders

“…MRI techniques including diffusion-weighted imaging (DWI) and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) may provide additional information about perfusion as well as early cartilage damage. DWI shows increased diffusion in affected femoral heads in both early and reparative stages of disease [ 70 ]. The dGEMRIC technique may provide information about early cartilage damage that is not apparent on standard imaging.…”