[The measurement of the femoral torsion angle in children by NMR tomography compared to CT and ultrasound].
OBJECTIVE
Anteversion of the femoral neck was measured by MRI in 19 children (37 hips) preoperatively before femoral rotation osteotomies.


METHODS
The results of this new technique were compared with values for anteversion obtained by CT and ultrasound. The measurements were performed independently by two observers to determine the correlation between the three different methods and to assess their reliability.


RESULTS
It was possible to show a high correlation coefficient (Pearson) between MRI and CT (r = 0.77) as well as MRI and sonography (r = 0.81). The mean angles obtained by CT (34 degrees, range +5 to +82 degrees) and ultrasound (25.6 degrees, range +10 to +40 degrees) appeared larger than the MRI values (mean angle 23.2 degrees, range 0 to +65 degrees), which can be explained by the different measurement techniques. Mean inter- and intra-variability was low for MRI (r = 0.97 and r = 0.97) and CT (r = 0.99 and r = 0.96) but slightly higher for sonography (r = 0.88 and r = 0.88). MRI is a new reliable and precise method to evaluate femoral anteversion that does not require ionising radiation.


CONCLUSIONS
MRI is recommended for preoperative planning of paediatric femoral rotation osteotomy patients.
Tomczak
R
R
Abteilung für Röntgendiagnostik, Universitätsklinik Ulm.
Günther
K
K
Pfeifer
T
T
Häberle
H J
HJ
Rieber
A
A
Danz
B
B
Rilinger
N
N
Friedrich
J M
JM
Brambs
H J
HJ
D000293:Adolescent; D001696:Biomechanical Phenomena; D002648:Child; D002675:Child, Preschool; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000706:statistics & numerical data; D014102:Torsion Abnormality; D014463:Ultrasonography
Messung des femoralen Torsionswinkels von Kindern durch Magnetresonanztomographie im Vergleich mit CT und Ultraschall.