Current treatments for Perthes disease are most effective when applied during the early stages of Perthes disease, prior to the femoral head collapsing and breaking apart. Radiographic prognosticators during these early stages of Perthes Disease are needed to guide treatment decisions. Commonly, patients receive x-rays to evaluate the extent of involvement of the femoral head. MRI provides 3D imaging of the femoral head and gadolinium-enhanced MRI with subtraction technique reveals information about the blood flow to the head. This technique can reveal early ischemia prior to significant flattening and fragmentation of the bone in the later stages of the disease.

Dr Harry Kim and the research team at Texas Scottish Rite Hospital for Children investigated pre and postcontrast MRI for reliability of measuring the amount of femoral head necrosis involvement during the initial stage of Perthes disease. Patients diagnosed with Perthes disease between the ages of 6 and 14 in Waldenström stage 1 of the disease were prospectively enrolled. Each child received an MRI with and without contrast as soon as possible after initial examination. The area of head involvement was measured on each MRI by 3 pediatric radiologists and 1 pediatric orthopedic surgeon.

Authors concluded that the postcontrast MRI showed greater reliability in measuring the area of head involvement. They qualitatively agreed that the contrast-enhanced MRI more clearly showed this area.

Reference: A comparison of non-contrast and contrast-enhanced MRI in the initial stage of Legg-Calvé-Perthes disease. HKW Kim, Kaste S, Dempsey M, and Wilkes D. Pediatric Radiology PMID: 23478799 [Epub ahead of print]