Table 2.

Dataset 2 MRI variables included in the analysis for each one of the spinal segments L1-S1. A total of 19 MRI variables are defined

Variable	Image source	Definition
multifidusFF	IDEAL	(Quantitative). Fat fraction of multifidus cross-sectional area. Average between left and right muscle
erectorspinaeFF	IDEAL	(Quantitative). Fat fraction of erector spinae cross-sectional area. Average between left and right muscle
CEPdx	UTE	(Qualitative). Whether there was presence (1) or absence (0) of Cartilage Endplate damage within either superior or inferior endplates at a given lumbar disk level
MC	T1 & T2	(Qualitative). Whether there was presence (1) or absence (0) of Modic Changes within either superior or inferior endplates at a given lumbar disk level