title: Magnetic Resonance Three-dimensional Cube Technique in the Measurement of Piglet Femoral Anteversion.
abstract: BACKGROUND
  The accurate measurement of the femoral anteversion (FA) angle is always a topic of much debate in the orthopedic surgery and radiology research. We aimed to explore a new FA measurement method to acquire accurate results without radiation damage using piglet model.
  
  
  METHODS
  A total of thirty piglets were assigned to two groups based on the age. Bilateral femora were imaged with 3.0-T magnetic resonance (MR) and 64-slice computed tomography (CT) examinations on all piglets. FA was measured on MR-three-dimensional (3D) postprocessing software with a four-step method: initial validation of the femoral condylar axis, validation of the condylar plane, validation of the femoral neck axis, and line-plane angle measurement of FA. After MR and CT examinations, all piglets were sacrificed and their degree of FA was measured using their excised, dried femora. MR, CT, and dried-femur measurement results were analyzed statistically; MR and CT measurements were compared for accuracy against each other and against the gold standard dried femur measurement.
  
  
  RESULTS
  In both groups, the mean FA value measured by MR was lower than that measured by CT. A statistically significant difference was observed between CT- and dried-femur measurements but not between MR- and dried-femur measurements. A higher correlation (0.783 vs. 0.408) and a higher consistency (0.863 vs. 0.578) with dried-femur measurement results were seen for MR measurements than CT measurements in the 1-week age group. However, in the 8-week age group, similar correlations (0.707 vs. 0.669) and consistencies (0.864 vs. 0.821) were observed.
  
  
  CONCLUSIONS
  Noninvasive MR-3D-Cube reconstruction was able to accurately measure FA in piglets. Particularly in the 1-week age group with a larger proportion of cartilaginous structures, the correlation and consistency between MR- and dried-femur measurement results were higher than those between CT- and dried-femur measurements, suggesting that MR may be a new useful examination tool for FA-related diseases in children.
authors.affiliation: Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China.
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Sun
authors.affiliation: Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China.
authors.forename: Shi-Nong
authors.initials: SN
authors.lastname: Pan
authors.affiliation: Department of Pediatric Orthopedics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China.
authors.forename: En-Bo
authors.initials: EB
authors.lastname: Wang
authors.affiliation: Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China.
authors.forename: Li-Qiang
authors.initials: LQ
authors.lastname: Zheng
authors.affiliation: Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China.
authors.forename: Wen-Li
authors.initials: WL
authors.lastname: Guo
authors.affiliation: Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China.
authors.forename: Xi-Hu
authors.initials: XH
authors.lastname: Fu
mesh_terms: D000818:Animals; D060750:Bone Anteversion / Q000175:diagnosis*; D005272:Femur Neck / Q000473:pathology*; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D013552:Swine; D014057:Tomography, X-Ray Computed