A comparison of non-contrast and contrast-enhanced MRI in the initial stage of Legg-Calvé-Perthes disease
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A prognostic indicator of outcome for Legg-Calvé-Perthes disease (LCP) is needed to guide treatment decisions during the initial stage of the disease (stage 1), before deformity occurs. Radiographic prognosticators are applicable only after fragmentation (stage II).
We investigated pre- and postcontrast MRI in depicting stage I femoral head involvement.
Materials and methods
Thirty children with stage I LCP underwent non-contrast coronal T1 fast spin-echo (FSE) and corresponding postcontrast fat-suppressed T1-weighted fast spin-echo (FSE) sequences to quantify the extent of femoral head involvement. Three pediatric radiologists and one pediatric orthopedic surgeon independently measured central head involvement.
Interobserver reliability of percent head involvement using non-contrasted MR images had intraclass correlation coefficient (ICC) of 0.72. Postcontrast MRI improved interobserver reliability (ICC 0.82). Qualitatively, the area of involvement was more clearly visible on contrast-enhanced MRI. A comparison of results obtained by each observer using the two MRI techniques showed no correlation. ICC ranged from −0.08 to 0.03 for each observer. Generally, greater head involvement was depicted by contrast compared with non-contrast MRI (Pearson r = −0.37, P = 0.04).
Pre- and postcontrast MRI assess two different components of stage I LCP. However, contrast-enhanced MRI more clearly depicts the area of involvement.
KeywordsLegg-Calvé-Perthes disease Hip Avascular necrosis Femoral head Pediatric Contrast MRI Perfusion MRI
The authors thank Dr. Richard Browne for statistical analysis, Lela Paksoy for administrative coordination of this project and Sandra Gaither for manuscript preparation. This work was supported in part by funding from Texas Scottish Rite Hospital for Children, St. Jude Children’s Research Hospital, American Lebanese Syrian Associated Charities and the International Perthes Study Group.
Conflicts of interest