Study of the Relation Between the Fat Infiltration of the Multifidus Muscle and the Lumbar Foraminal Stenosis, by 2D and 3D Segmentation

The aim of this study is to evaluate the correlation between the fat infiltration of the lumbar multifidus muscle and several parameters including the severity of the lumbar foraminal stenosis. The investigators will analyse lumbar MRI of patients previously included in a database of patients suffering from low back pain. Foraminal stenosis, muscle fat infiltration and other imaging lumbar parameters will be studied by 2D and 3D manuel segmentation, semi-automatic segmentation. Correlations between factors influencing the muscle fat infiltration will be studied by univariate and multivariate statistical analysis.