Abstract
This pilot study aims to investigate the utility and feasibility of a unique upright MR scan for imaging hips affected by Legg-Calve-Perthes Disease (LCPD) with patient standing up, in comparison to the standard supine scans.
Protocol development using this unique upright MRI included healthy adult and child volunteers. Optimum patient positioning in a comparable way between supine to standing was assessed. The balance between shorter scan time (to what a child can tolerate) and longer scan time (for better image acquisition). The study protocol has begun in 2 children with LCPD. Patient recruitment continues.
Early results indicate a dynamic deformity of the femoral head in early stage LCP disease. Femoral epiphysis height decreased on standing (7.8 to 6.8mm), width increased on standing (16.6 to 20.9mm) and lateral extrusion increased (3.5 to 4.1mm). Overall epiphyseal shape changed from trapezoidal (LCP femoral head when supine) to flattened triangular (LCP femoral head when standing). Differences were thus demonstrated in all parameters of bony epiphyseal height, width, extrusion and shape of a femoral head with LCP Disease when the child stood and loaded the affected hip.
Satisfactory image acquisition was possible with Coronal T1 GFE sequences, with both hips in the Field of View. 2.5min scans were performed with the child standing first, then supine. Hip position was comparable when standing and supine. Longer scans were not tolerated by younger children, more so those with LCP disease.
To our knowledge this is the first reported use of standing MRI in LCPD. A dynamic deformity has been demonstrated, with flattening, widening and worsened lateral extrusion when the child is standing compared to supine. This proof of concept investigation demonstrates the feasibility of upright MRI scanning and may demonstrate previously undetected deformity.
