Fig. 4.

Analysis of multifidus fat maps using SPM t-tests reveal the individual and interactive associations of pain and pathology with spatial FI distributions Top row: Analysis of patient subgroups stratified by the presence of CEP damage (left) shows significantly greater FI% in regions of the multifidus in patients with CEP compared to patients without CEP. Additionally, comparing patients with CEP damage to controls with CEP damage (middle) reveals significantly larger FI% for patients in regions of the multifidus which are not significant in the original, unstratified patients vs. controls assessment (Fig. 2, top). Lastly, the multifidus fat-maps for patients without CEP did not differ from controls without CEP. Bottom row: Similar to CEP, stratifying patients based on high (> 3) and low(< = 3) PG revealed significant differences in FI distribution. Patients with high PG had significantly greater FI compared to patients with low PG (left) and controls (middle). However, there were no significant differences in the FI% in any region of the multifidus when comparing patients and controls with low PG (right). These results show that the presence of degenerative IVD pathology is associated with spatial differences in multifidus FI within patients, but the presence of symptoms in the absence of pathology is not a distinguishing factor in the spatial distribution of multifidus FI