Correlation of magnetic resonance imaging biomarkers (tissue bridges) with neurological recovery following traumatic spinal cord injury

Table 1 Details of acquisition of magnetic resonance images

		Axial TR	Slice gap	Slice thickness (mm)	FOV (cm)	NEX	TE
T1	Plan	650	1	4	1	2	10
T2	Sagittal	3841	1	4	0.80	2	102
T1	Sagittal	2671	1	4	1	2	24
T2	Axial	6847	1	4	0.80	3	112

TR: Repetition time; FOV: Field of view; NEX: Number of excitations; TE: Echo time.

Table 2 Demographic data of the cohort

Variable		Frequency	Percentage (%)
Age (year)	< 30	10	21.3
	31-40	9	19.1
	41-50	22	46.8
	> 60	6	12.8
Gender	Female	13	27.7
	Male	34	72.3
Socio economic status	Lower class	17	36.2
	Lower middle class	21	44.7
	Upper middle class	9	19.1
Marital status	Married	43	91.5
	Unmarried	4	8.5
Educational status	Higher sec certificate	7	14.9
	Secondary	3	6.4
	Middle school	4	8.5
	Primary school	12	25.5
	Illiterate	21	44.7
Level of injury	Cervical	8	17.02
	Upper dorsal (up to D5)	8	17.02
	Lower dorsal (D6-D11)	16	34.04
	Thoracolumbar area (D12-L2)	15	31.91
Mode of injury	Diving injury	4	8.5
	Fall	7	14.9
	Fall from height	14	29.8
	Motorcycle injury	9	19.1
	RSA	13	27.7

RSA: Road side accident.

Table 3 Distribution of subjects according to their symptomatology

Pain		Initial		1 month		3 months		6 months		P value1
		No. of cases	Percentage (%)	No. of cases	Percentage (%)	No. of cases	Percentage (%)	No. of cases	Percentage (%)
Pain score (VAS)	No	0	0.0	20	42.6%	47	100.0	47	100.0	< 0.001
	Mild	0	0.0	22	46.8%	0	0.0	0	0.0
	Moderate	0	0.0	5	10.6%	0	0.0	0	0.0
	Severe	47	100.0	0	0.0%	0	0.0	0	0.0
Swelling		47	100.00	5	10	4	8.50	3	6.40	< 0.001
Deformity		5	10.60	5	10.60	5	10.60	5	10.60	< 0.001
Weakness-lower limb		47	100.00	47	100.00	10	21.30	10	21.30	0.008
Weakness-upper limb		5	10.60	0	0.00	3	6.40	3	6.40	< 0.001
Incontinence		47	100.00	3	6.40	0	0.00	0	0.00	< 0.001
Retention		47	100.00	3	6.40	0	0.00	0	0.00

¹Cochran’s Q test.

VAS: Visual analog scale.

Table 4 Comparison motor index score and sensory index score at the 1-month, 3-month and 6-month intervals

MIS		Mean	SD	t value	P value1	Difference			95% confidence interval of the difference
						Mean	SD	SE mean	Lower	Upper
MIS upper limb (month)	1	44.32	6.29
	3	44.85	6.31	-5.080	0.001	-0.53	0.72	0.10	-0.74	-0.32
	6	45.68	5.75	-6.643	0.001	-1.36	1.41	0.20	-1.77	-0.95
MIS lower limb	1	31.21	14.57
	3	34.57	13.74	-5.601	0.001	-3.36	4.11	0.60	-4.57	-2.15
	6	38.23	13.63	-6.466	0.001	-7.02	7.44	1.09	-9.21	-4.84
Total (MIS)	1	75.53	14.99
	3	79.43	15.13	-6.699	0.001	-3.89	3.98	0.58	-5.06	-2.72
	6	83.91	15.54	-8.358	0.001	-8.38	6.88	1.00	-10.40	-6.36
SIS light touch (R + L)	1	92.60	17.41
	3	94.74	17.24	-12.121	0.001	-2.15	1.22	0.18	-2.51	-1.79
	6	99.85	17.88	-11.647	0.001	-7.26	4.27	0.62	-8.51	-6.00
SIS pin prick (R + L)	1	93.55	17.32
	3	96.21	17.35	-8.109	0.001	-2.66	2.25	0.33	-3.32	-2.00
	6	101.13	17.58	-11.678	0.001	-7.57	4.45	0.65	-8.88	-6.27
Total SIS	1	186.15	34.50
	3	190.96	34.30	-12.632	0.001	-4.81	2.61	0.38	-5.57	-4.04
	6	200.98	35.16	-14.144	0.001	-14.83	7.19	1.05	-16.94	-12.72

¹Repeated measures ANOVA.

n = 47 at all-time points for all variables. MIS: Motor index score; SIS: Sensory index score; R: Right; L: Left.

Table 5 Distribution of subjects according to neurological parameters on clinical examination

Variables		1 month		3 months		6 months		P value1
		No. of cases	Percentage (%)	No. of cases	Percentage (%)	No. of cases	Percentage (%)
ASIA score	A	10	21.3	2	4.3	2	4.3	0.548
	B	0	0	0	0	0	0
	C	10	21.3	12	25.5	9	19.1
	D	22	46.8	28	59.6	21	44.7
	E	5	10.6	5	10.6	15	31.9
Voluntary anal contraction	0	14	29.8	17	36.2	14	29.8	0.857
	1	22	46.8	22	46.8	22	46.8
	2	11	23.4	8	17.0	11	23.4
Temperature		8	17.0	4	8.5	0	0.0	0.345
Deep anal pressure		12	25.5	4	8.5	0	0.0	0.548
Superficial reflexes	Abdominal reflex (absent)	18	40	4	8.0	4	8.0	< 0.001
	Babinski reflex (absent)	47	100	47	100	47	100	-
	Patellar (absent)	18	40.0	8	16.0	6	12.0	< 0.05
	Ankle (absent)	18	40.0	8	16.0	4	8.0	< 0.01
	Clonus (absent)	47	100	47	100	47	100	-

¹Cochran’s Q test.

n = 47 at all-time points for all variables.

Table 6 The radiological indices at various time intervals

Radiological variables	Time interval in months	Mean	SD	t value	P value1	Difference			95% confidence interval of the difference
						Mean	SD	SE mean	Lower	Upper
Sagittal index	1	10.30	3.20
	3	5.41	2.19	12.468	0.000	4.88	2.68	0.39	4.09	5.67
	6	4.70	1.56	12.140	0.000	5.60	3.16	0.46	4.67	6.52
Regional kyphosis	1	17.40	2.60
	3	16.68	2.12	2.174	0.035	0.72	2.28	0.33	0.05	1.39
	6	16.76	2.08	2.028	0.048	0.65	2.19	0.32	0.00	1.29
Gardener segmental kyphotic deformity	1	16.00	0.42
	3	15.47	1.63	2.477	0.017	0.53	1.47	0.21	0.10	0.96
	6	15.47	1.64	2.452	0.018	0.53	1.49	0.22	0.10	0.97

¹Repeated measures ANOVA.

n = 47 at all-time points for all variables.

Table 7 Correlation coefficients and P-values for the relationship between radiological measurements at 1 and 6 months (sagittal index, regional kyphosis, gardener segmental kyphotic deformity) and magnetic resonance imaging parameters related to tissue bridges at 1 and 6 months

MRI parameters at 1 month	1 month				6 months
	Spearman’s rho	Sagittal index	Regional kyphosis	Gardener segmental kyphotic deformity	Sagittal index	Regional kyphosis	Gardener segmental kyphotic deformity
Ventral tissue bridge	Correlation coefficient	0.006	0.108	0.226	-0.161	0.134	0.073
	P value	0.969	0.470	0.126	0.280	0.369	0.628
Dorsal tissue bridge	Correlation coefficient	0.024	0.047	-0.181	-0.055	-0.182	-0.094
	P value	0.871	0.753	0.224	0.714	0.221	0.529
Total width of tissue bridges	Correlation coefficient	0.037	0.082	0.152	-0.112	-0.019	0.045
	P value	0.806	0.583	0.307	0.452	0.901	0.766
Midsagittal tissue bridge ratios	Correlation coefficient	0.005	-0.011	-0.095	0.046	-0.116	-0.076
	P value	0.973	0.940	0.525	0.760	0.436	0.612

n = 47 at all-time points for all variables. MRI: Magnetic resonance imaging.

Table 8 Compares the mean and SD of lesion length, width, and area at different time intervals

MRI parameters	Mean	SD	t value	P value1	Difference			95% confidence interval of the difference
					Mean	SD	SE mean	Lower	Upper
Lesion length (mm)
1 month	33.96	27.09
3 months	18.43	14.68	4.808	0.001	15.53	22.14	3.23	9.03	22.03
6 months	14.14	15.59	4.837	0.001	19.82	28.09	4.10	11.57	28.07
Lesion width (mm)
1 month	4.65	1.76
3 months	3.94	1.65	4.900	0.001	0.71	0.99	0.14	0.42	1.00
6 months	3.57	1.73	6.957	0.001	1.07	1.06	0.15	0.76	1.39
Lesion area (mm2)
1 month	110.66	83.41
3 months	80.05	32.29	2.532	0.015	30.61	82.88	12.09	6.27	54.94
6 months	73.35	37.22	2.700	0.010	37.31	94.76	13.82	9.49	65.14

¹Repeated measures ANOVA.

n = 47 at all-time points for all variables. MRI: Magnetic resonance imaging.

Table 9 Regression analysis between various clinical measures at 6 months and magnetic resonance parameters at 1 month

Clinical measure at 6 months; dependent variable	MR parameter at 1 month; independent variable	R	R square	P value1	Standardized regression coefficients	95% confidence interval
						Lower bound	Upper bound
MIS upper limb	MSCC	0.454	0.206	0.001	-1.442	-2.291	-0.592
	MCC	0.135	0.018	0.365	-0.232	-0.744	0.279
	Lesion length (mm)	0.098	0.010	0.513	0.021	-0.043	0.084
	Lesion width (mm)	0.030	0.001	0.840	0.099	-0.879	1.076
	Lesion area (mm2)	0.217	0.047	0.142	0.015	-0.005	0.035
	Total width of tissue bridges	0.301	0.090	0.040	3.755	0.179	7.332
	Midsagittal tissue bridge ratios	0.342	0.117	0.019	25.095	4.408	45.781
MIS lower limb	MSCC	0.194	0.038	0.192	-1.459	-3.676	0.759
	MCC	0.144	0.021	0.333	-0.588	-1.798	0.622
	Lesion length (mm)	0.242	0.059	0.101	-0.122	-0.268	0.025
	Lesion width (mm)	0.368	0.135	0.011	-2.841	-4.997	-0.685
	Lesion area (mm2)	0.286	0.082	0.051	-0.047	-0.094	0.000
	Total width of tissue bridges	0.209	0.044	0.159	6.182	-2.512	14.876
	Midsagittal tissue bridge ratios	0.146	0.021	0.328	25.355	-26.281	76.991
Total (MIS)	MSCC	0.338	0.114	0.020	-2.900	-5.326	-0.475
	MCC	0.177	0.031	0.235	-0.820	-2.193	0.552
	Lesion length (mm)	0.176	0.031	0.237	-0.101	-0.271	0.069
	Lesion width (mm)	0.311	0.097	0.033	-2.743	-5.255	-0.231
	Lesion area (mm2)	0.171	0.029	0.251	-0.032	-0.087	0.023
	Total width of tissue bridges	0.294	0.087	0.045	9.937	0.250	19.625
	Midsagittal tissue bridge ratios	0.255	0.065	0.084	50.450	-7.101	108.000
SIS light touch	MSCC	0.359	0.129	0.013	-3.543	-6.312	-0.775
	MCC	0.402	0.162	0.005	-2.149	-3.618	-0.679
	Lesion length (mm)	0.145	0.021	0.330	-0.096	-0.292	0.100
	Lesion width (mm)	0.341	0.116	0.019	-3.458	-6.318	-0.598
	Lesion area (mm2)	0.337	0.114	0.021	-0.072	-0.133	-0.012
	Total width of tissue bridges	0.077	0.006	0.608	2.985	-8.646	14.616
	Midsagittal tissue bridge ratios	0.069	0.005	0.645	15.748	-52.577	84.073
SIS pin prick	MSCC	0.353	0.125	0.015	-3.427	-6.155	-0.700
	MCC	0.333	0.111	0.022	-1.748	-3.236	-0.261
	Lesion length (mm)	0.086	0.007	0.565	-0.056	-0.250	0.138
	Lesion width (mm)	0.322	0.104	0.027	-3.206	-6.037	-0.375
	Lesion area (mm2)	0.264	0.070	0.073	-0.056	-0.117	0.005
	Total width of tissue bridges	0.064	0.004	0.670	2.434	-9.008	13.876
	Midsagittal tissue bridge ratios	0.084	0.007	0.576	18.770	-48.307	85.846
Total SIS	MSCC	0.359	0.129	0.013	-6.971	-12.413	-1.528
	MCC	0.371	0.137	0.010	-3.897	-6.828	-0.966
	Lesion length (mm)	0.117	0.014	0.434	-0.152	-0.539	0.235
	Lesion width (mm)	0.334	0.112	0.022	-6.664	-12.301	-1.027
	Lesion area (mm2)	0.303	0.092	0.038	-0.128	-0.248	-0.007
	Total width of tissue bridges	0.071	0.005	0.636	5.419	-17.459	28.297
	Midsagittal tissue bridge ratios	0.077	0.006	0.607	34.518	-99.736	168.773

¹Spearman's rho correlation.

n = 47 at all-time points for all variables. MR: Magnetic resonance; MIS: Motor index score; SIS: Sensory index score; MSCC: Maximum spinal cord compression; MCC: Maximum canal compromise.