Magnetic resonance imaging (MRI) for assessment of differences in geometrical parameters in muscles stabilizing vertebral column in young and older persons. Case study.

Today non-traumatic low back pain (LBP) is a social disease being attributed to weakening the function of abdominal and back muscles. Condition of deep muscles, inaccessible to non-invasive examinations, can be assessed by means of magnetic resonance imaging (MRI). The method allows for the assessment of cross-sections, muscle girths, as well as their intensity (brightness). The aim of the investigations was to determine the opportunities to employ MRI technique for assessing the geometry of muscles which stabilize spinal column. The study covered 4 women without LBP symptoms. The cross-sectional area, thickness and brightness of abdominal and back muscles were measured at the level of L3-L4. Measurement of geometrical parameters in the positions studied was aimed at setting such measurement conditions that would force higher isometric contraction in the muscles examined. As a result of measurements it can be inferred that other conditions of the experiment affect neither an increase in cross-sectional surface area nor the thickness of the muscles examined. The differences observed in geometrical parameters of the muscles testify to different coordination of muscle activation in the positions studied, both in young and older subjects, and to the purposefulness of continuing this type of measurements.