Fig 1.
Number of imaging-related lumbar multifidus muscle research publications by decade: 1990–2017.
MRI: magnetic resonance imaging; DUS: diagnostic ultrasound; CT: computed tomography [Databases: PubMed, Web of Science, Embase, SPORTDiscus, PEDro, CINAHL].
Fig 2.
Different measurement procedure examples.
A: Histogram outlining process. B: Histogram from A. Small white box indicates the region of intersection of the green histogram line with the X-axis at “0”. Note: to identify the point at which the histogram curve contacted the X-axis to the nearest value of 10, one must zoom in on the histogram within the sliceOmatic program. The inset box shows the point of intersection of the green histogram line with the X-axis, indicated by the blue line. In this example, the cut-off point would be 170. C: Overlapped T1-weighted and T2-weighted total cross-sectional area outlines for visual comparison. D: Fat (bright green/pale green) and muscle (red/purple) tissue highlighted, with related measurement outcomes [surf. measures (cm2) apply].
Fig 3.
Bland-Altman plots for between-sequence measures.
A & B: Total cross-sectional area (CSA) measures of the lumbar multifidi bilaterally at L4 and L5, respectively. C & D: Total fat area as a percentage of Total CSA (Fat %) bilaterally at L4 and L5, respectively.
Table 1.
Bland-Altman analysis: T1 and T2-weighted measures for total cross-sectional area (TCSA) and percentage fat (Fat %).
Table 2.
Ratings for visual assessment of muscle outline.
Table 3.
Cases requiring consensus between raters for visual assessment of muscle outline.
Table 4.
Intra-rater reliability for measurement of cross-sectional area (CSA).
Fig 4.
Bland-Altman plots for intra-rater assessment of total CSA.
A & B: Measures of the lumbar multifidi at L4 for T1 and T2-weighted imaging, respectively. C & D: Measures of the lumbar multifidi at L5 for T1 and T2-weighted imaging, respectively.
Table 5.
Bland-Altman analysis: Intra-rater measurement of total cross-sectional area (TCSA) and percentage fat (Fat %).
Fig 5.
Bland-Altman plots for intra-rater assessment of fat percentage (Fat %) of total CSA.
A & B: Measures of the lumbar multifidi Fat % at L4 for T1 and T2-weighted imaging, respectively. C & D: Measures of the lumbar multifidi Fat % at L5 for T1 and T2-weighted imaging, respectively.
Fig 6.
Examples of subtle but important variations in appearance of anatomy.
A & B: T2-weighted and T1-weighted sequences with cross-sectional outlines. Note obvious differences in outlining adjacent to the facet joint on the right and lateral muscle margin on the left, both rated at 2 for mismatch. C: T2-weighted image (original). Arrows highlight the subtle fascial plane used by the examiner as the dividing line between multifidus and erector spinae muscle groups; white dotted circle highlights obvious bone hypertrophy from facet arthrosis, not included by the examiner. D: T1-weighted image (original). Arrows with “?” highlight the absence of a clear fascial plane, with two potential options open to the examiner–the outer option was used; white dotted circle highlights same region as image C, but the type of tissue is not as obvious, and was included as muscle on the T1 image.