Table 1.

A non-systematic summary of methods across investigations describing cervical spine muscle analysis using magnetic resonance imaging (MRI)

Citation	Reliability	MRI Sequence	Slice Selection	Muscles of Interest	ROI Selection	Fat Detection	Measure
Elliott et al., 2006 [1] Elliott et al., 2008 [7] Elliott et al., 2009 [78] Elliott et al., 2011 [2]	Inter-rater (0.94) Intra-rater (0.94)	T1	Axial images aligned parallel to C2–3 disc; Measured at single slice per level C3-C7; most cephalad slice of each vertebral body selected	MF SSCerv SSCap SpCap UT	Manual	Quantitative Pixel Intensity	Fat Infiltration %MFI = (muscle signal)/(fat signal)*100
Fernandez De Las Penas et al., 2007 [79]	Inter-rater (0.80–0.98)	T1	Axial images aligned parallel to C2–3 disc; measured at single slice per level; most cephalad slice of each vertebral body selected	SSCap SpCap	Manual	N/A	CSA
Elliott et al., 2007 [47]	Intra-rater (0.84–0.99) Inter-rater (0.89–0.96)	T1	Axial images aligned parallel to C2–3 disc; measured at single slice per level C3-C7; most cephalad slice of each vertebral body selected	MF SSCerv SSCap SpCap UT	Manual	N/A	CSA
Okada et al., 2011 [80] Matsumoto et al., 2012 [12]	Intra- rater (0.90) Inter-rater (0.844)	T2	Measurements from a single axial slice aligned parallel to each IVD C3–4, C4–5, and C5–6	MF SSCerv SSCap SpCap	Manual	N/A	CSA
Ulbrich et al., 2012 [14]	Inter-rater (0.79–0.98)	STIR	Axial images aligned perpendicular to the vertebral body in the middle of a 20-slice slab. 2 or 3 overlapping slabs used; measurements from single slice per vertebral level C2, C4, and C5	Deep Extensors All Extensors SCM	Manual	N/A	CSA
Elliott et al., 2013 [41]	Inter-rater for fat-water sequence (0.83–0.99)	T1 vs. Dixon	Axial images aligned perpendicular to the spinal cord at the C2-C3 IVD; measurement from single slice per vertebral level C3-C7	MF	Manual	Quantitative Pixel Intensity vs. Fat (F)-Water (W)	Fat Infiltration % MFI = (fat signal)/(fat signal + water signal) *100
Elliott et al., 2014 [8]	From Elliott et al., 2007 [47] for CSA Intra- rater (0.84–0.99) Inter-rater (0.89–0.96)	T1	Axial images aligned parallel to C2–3 IVD; measurements from single slice crossing IVDs C2-C3 and C5-C6	MF SSCerv SSCap SpCap LCap/LCol SCM	Manual	Quantitative Pixel Intensity	Fat Infiltration %MFI = (fat signal)/(fat signal + water signal)*100 CSA
Elliott et al., 2015 [3]	Not reported	Dixon	Measurements from single slice per vertebral level C3-C7; alignment and slice selection not reported	MF	Manual	Fat-Water	Fat Infiltration %MFI = (fat signal)/(fat signal + water signal)*100
Abbott et al., 2015 [6]	Intra-rater (0.98) Inter-rater (0.93)	Dixon	Measurements averaged over 5 slices for each vertebral level C3-C7; Slab alignment not reported.	MF + SSCerv (combined)	Manual with automatic quartile measure	Fat-Water	Fat Infiltration %MFI = (fat signal)/(fat signal + water signal)*100
Karlsson et al., 2016 [5]	For muscle fat Intra-rater (0.81–0.93) Inter-rater (0.82–0.97)	Dixon	Axial images aligned parallel to vertebral segments; measurements averaged over 5 slices for each vertebral level C4-C7	MF	Manual	Fat-Water	Fat Infiltration %MFI = (fat signal)/(fat signal + water signal)*100 CSA
Au et al., 2016 [57]	Not reported	T1	Axial images aligned parallel to C2–3 intervertebral disc; 3D reconstruction	IC, IS, LS, LoCap, LoC, LCap, LCol, MF, LoCap, LoCerv, SSCap, SSCerv, SCM, UT	Manual	N/A	N/A
Fortin et al., 2017 [27] Fortin et al., 2018 [81]	From [81]:Intra-rater (0.83–0.99) Inter-rater (0.38–0.98)	T2	3D multiplanar reconstruction to align images perpendicular to muscle mass; measurements from a single slice per IVD C2–3 through C6–7	MF SSCerv SSCap SpCap	Manual ROI with semi-automatic muscle/fat thresholding technique	Gray-scale threshold technique to calculate CSA of fat within total muscle CSA; gray-scale range determined for each slice individually	Total CSA Functional CSA (FCSA) (= fat free area) Fatty Infiltration = FCSA/Total CSA
Inoue et al., 2012 [82]	Intra-rater (0.85)	T1 T2-fat suppression	Measured from single slice per level; most caudal slice of C3 and most cephalad slice of each vertebral body C4-C7 selected; slab alignment not reported	MF	Manual	Lean muscle CSA: ROI drawn on T1-W images not including fat Total muscle CSA: ROI drawn on fat suppression T2-W image including fat Fat CSA = Total CSA – Lean Muscle CSA	Fatty Infiltration = (Fat CSA)/(Total muscle CSA)
Mitsutake et al., 2016 [83]	Intra-rater 0.85–0.94 Inter-rater (0.84–0.89)	T1	Measured from single, most cephalad slice at level of injury (C4, C5, or C6)	MF	Manual	Quantitative Pixel Intensity	MFI index = Muscle signal/Fat signal
Abbott et al., 2017 [67]	Intra-rater (0.77–0.88) Inter-rater (0.67–0.82)	Dixon	Axial images aligned parallel to each IVD; measured from 5 slices across each vertebral level C4-C7	MF	Manual	Qualitative grading (0, 1, 2) for each 8 regions within visualized ROI on fat image	Fat Infiltration MFI Score: 0 = no or marginal fat 1 = light fat 2 = distinct fat Sum of scores Total # of 2’s
Choi et al., 2016 [84]	Inter-rater (0.82)	T1	Axial images aligned parallel to the inferior end plate of each vertebral body from C4–5 to C7-T1; measured from single slice per vertebral level	Flexor Group: LCap + LCol Extensor Group: MF + SSCerv	Manual	N/A	CSA Normalized Extensor CSA = (Extensor Muscle CSA)/(Vertebral body CSA) *100
Cagnie et al., 2009 [85]	Inter-rater (0.91)	T1	Measured from a single slice aligned parallel IVD at C4-C5	LCap LCol UT LS SpCap SSCerv MF	Manual	Quantitative Pixel Intensity	Muscle/Fat Index = Muscle signal/Fat signal
Uthaikup et al., 2017 [86]	Intra-rater (0.75–0.96) Inter-rater (0.84–0.99)	T1	Axial images aligned parallel to the C2–3 IVD; measured from a single slice at each vertebral level C2-C3	MF SSCap SpCap LCap LCol SCM	Manual	Quantitative Pixel Intensity	Fat Infiltration MFI = Muscle signal/Fat signal