High-resolution, three-dimensional magnetic resonance imaging axial load dynamic study improves diagnostics of the lumbar spine in clinical practice

Table 1 Three-dimensional Volume ISotropic Turbo spin-echo Acquisition magnetic resonance pulse parameters

Parameters	3D VISTA T2
Repetition time/Echo time (ms)	2000/90
Number of signal averaging	1
Field of View (mm)	300 × 200 × 75
Acquisition matrix	300 × 196
Acquisition voxel (mm)	1 × 1 × 0.5
Reconstruction matrix	640
Reconstruction voxel (mm)	0.47 × 0.47 × 0.5
Turbo factor	61
Sensitivity encoding factor	1.3
Scan time	06:46

3D: Three-dimensional; VISTA: Volume ISotropic Turbo spin-echo Acquisition.

Table 2 Cross-sectional area of the ligamentum flavum on the same levels with and without axial loading on both sides

Ligamenta flava(right + left) / section of the spine	Mean difference of area between unloaded and axial loading (%)	95%CI		P value
		Lower	Upper
L1-L2	4.1	1.8	6.4	0.001
L2-L3	4.8	2.0	7.6	0.001
L3-L4	4.0	0.5	4.7	0.024
L4-L5	2.1	-0.5	6.3	0.116
L5-S1	4.1	2.5	5.2	< 0.001
All from L1-L2 to L5-S1	3.8	2.5	5.2	< 0.001

Negative value corresponds to a decrease. CI: Confidence interval.

Table 3 Percentage difference of the cross-sectional area of the dural sac on transverse, T2-dependent magnetic resonance imaging at the same levels for phases both with and without axial loading

Dural sac/section of the spine	Mean difference of area between unloaded and axial loading (%)	95%CI		P value
		Lower	Upper
L1-L2	-2.6	-3.6	-1.6	< 0.001
L2-L3	-5.5	-6.8	-4.2	< 0.001
L3-L4	-6.7	-8.9	-4.4	< 0.001
L4-L5	-8.1	-10.5	-5.7	< 0.001
L5-S1	-3.0	-4.9	-1.0	0.004
All from L1-L2 to L5-S1	-5.2	-6.2	-4.1	< 0.001

Negative values correspond to a decrease. CI: Confidence interval.

Table 4 Percentage difference of the sagittal cross-sectional area of vertebral foramina on the same levels both with and without axial loading on both sides

Intervertebral foramina (right + left)/section of the spine	Mean difference of area between unloaded and axial loading (%)	95%CI		P value
		Lower	Upper
L1-L2	-4.0	-5.1	-2.9	< 0.001
L2-L3	-6.7	-8.0	-5.5	< 0.001
L3-L4	-5.1	-6.2	-4.0	< 0.001
L4-L5	-3.3	-4.8	-1.7	< 0.001
L5-S1	2.0	0.5	3.9	0.045
All from L1-L2 to L5-S1	-3.4	-4.1	-2.7	< 0.001

Negative values correspond to a decrease. CI: Confidence interval.

Table 5 Percentage difference of the lumbosacral angles between L1 and S1 measured based on recumbent and axial-loaded magnetic resonance images

Lumbosacral angle	Mean difference of angle between unloaded and axial loading (%)	95%CI		P value
		Lower	Upper
From L1 to S1	7.7	5.7	9.6	< 0.001

CI: Confidence interval.

Table 6 Degenerative pathologies of the lumbar spine

Analyzed factors	Grade	n	%
Intervertebral disc degeneration according to Pfirrmann et al[38] classification	1	0	0
	2	72	16
	3	196	44
	4	159	35
	5	23	5
Facet joint degeneration, according to Weishaupt et al[39] classification	0	300	33
	1	405	45
	2	149	17
	3	46	5
Grade of lumbar spinal canal stenosis according to Schizas et al[40] classification	A1	349	78
	A2	22	5
	A3	47	10
	A4	3	1
	B	20	4
	C	7	2
	D	2	0
Disc herniation according to the Michigan State University[42] classification of lumbar disc herniation	0	342	76
	1a, 1b, 1ab, 1c	88	20
	2a, 2b, 2ab, 2c	18	4
	3a, 3b, 3ab, 3c	2	0
Foraminal stenosis, according to Lee et al[41] classification	0	664	74
	1	168	19
	2	56	6
	3	12	1