title: 3D MRI Quantification of Femoral Head Deformity in Legg-Calvé-Perthes Disease.
abstract: The purpose of this study was to quantify femoral head deformity in patients with Legg-Calvé-Perthes disease (LCPD) using a novel three dimensional (3D) magnetic resonance imaging (MRI) reconstruction and volume based analysis. Bilateral femoral heads of 17 patients (mean age 9.9 ± 2.0 years; 12 boys, 5 girls) with LCPD were scanned 1-2 times (n = 33 LCPD heads, 20 normal heads) using a 1.5T MRI scanner. Fourteen patients had unilateral and three had bilateral LCPD with five hips in the Waldenström initial stage, 9 in the fragmentation stage, 14 in the reossification stage, and 5 in the healed stage. 3D digital reconstructions of femoral heads were created using MIMICS software. Deformity was quantified using a 3D volume ratio method based on reference hemisphere volume as well as two surface geometry methods. Intra-observer analysis showed that 97% of the LCPD femoral heads were within 10% of the original value and test shapes had 99.6% accuracy. For normal femoral heads, the volume ratios of all except one were between 95 and 98% (n = 20) of a perfect hemisphere volume. For femoral heads affected with LCPD, the volume ratios ranged from 43% to 96% of a perfect hemisphere (n = 33). The volume ratio method and the two surface geometry comparison methods had high correlation (r = 0.89 and 0.96). In summary, the 3D MRI volume ratio method allowed accurate quantification and demonstrated small changes (<10%) of the femoral head deformity in LCPD. This method may serve as a useful tool to evaluate the effects of treatment on femoral head shape. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2051-2058, 2017.
authors.affiliation: Texas Scottish Rite Hospital for Children, Dallas, Texas.
authors.forename: Karen D
authors.initials: KD
authors.lastname: Standefer
authors.affiliation: Texas Scottish Rite Hospital for Children, Dallas, Texas.
authors.forename: Molly
authors.initials: M
authors.lastname: Dempsey
authors.affiliation: Texas Scottish Rite Hospital for Children, Dallas, Texas.
authors.forename: ChanHee
authors.initials: C
authors.lastname: Jo
authors.affiliation: Center for Excellence in Hip Disorders, Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas 75219, Texas.|Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Texas.
authors.forename: Harry K W
authors.initials: HKW
authors.lastname: Kim
mesh_terms: D002648:Child; D000070603:Coxa Magna / Q000000981:diagnostic imaging* / Q000209:etiology; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D021621:Imaging, Three-Dimensional; D007873:Legg-Calve-Perthes Disease / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male
keywords: 3D MRI; Legg-Calvé-Perthes disease; femoral head deformity; femoral head morphology; osteonecrosis