Introduction
The term myelopathy describes pathologic conditions that cause spinal cord, meningeal or perimeningeal space damage or dysfunction. Thus, myelopathy is a broad term that refers to spinal cord involvement of multiple etiologies and can be divided into compressive and non-compressive. Compressive diseases of the spinal cord are divided into acute and chronic, including degenerative changes, trauma, tumor infiltration, vascular malformations, infections with abscess formation.1
Spinal cord diseases often have devastating consequences, ranging from quadriplegia and paraplegia to severe sensory deficits. Many of these diseases are potentially reversible if recognized and treated at an early stage. Thus, they are among the most critical neurologic emergencies, where prognosis depends on an early and accurate diagnosis.1
In comparison with CT, MRI detects more traumatic disc herniations, epidural haematomas and spinal cord abnormality, though it is less sensitive in the detection of posterior element fractures. Now a days MR imaging has replaced CT in noninvasive evaluation of patients with painful myelopathy because of superior soft tissue resolution and multiplanar capability and hence can depicts the spinal cord directly, assesses its contour and internal signal intensity characteristics reliably and early.2
The present study highlights the various causes of compressive myelopathy and their characteristics evaluated by MRI with their distribution in demographic attributes of suspected cases.
Materials and Methods
After getting approval from the ethical committee of Patna Medical college, a descriptive hospital-based study was conducted in department of Radiology, Patna Medical College & Hospital, Patna for the duration of 18 months from February 2018 to August 2019.
Operational definition
For the purpose of this study Compressive myelopathy is conceptualized as the spinal cord compression either from outside or within the cord itself, excluding degenerative disc herniation.
By prospective sampling total 50 cases who attended / referred to the department with clinical suspicion of compressive myelopathy were selected.
Exclusion criteria
Cases of non – compressive myelopathy.
Degenerative disc herniation.
Cases with contraindication for MRI, like prosthetic heart valve, cochlear implant or any other orthopedic metallic implant.
All the cases were subjected to MRI examination using GE SIGNA EXPLORER 1.5 Tesla MR imaging unit. Standard surface coils and body coils were used for cervical, thoracic and lumbar spine for acquisition of images. Conventional spin echo sequences T1WI, T2WI, FLAIR Sag, STIR sag, T1WI, T2WI axial and GRE axial, and post contrast T2WI axial, Sag and coronal were done with with a FOV: Sagittal: 30cm, Axial: 18cm; Matrix size: 256x 256; Slice thickness: 4.5mm x 5mm; Contrast: Gd– DTPA at a dose of 0.1 mmol/kg body wt. If contrast was required, T1W fat saturated pre-contrast images (axial & sagittal) and T1W fat saturated post contrast (axial, sagittal & coronal) images were acquired in addition to routine sequences.
Thus, obtained data were coded and entered into SPSS version 20.0 (trial) and analyzed further.
Result & Discussion
Among 50 cases, most common cause for compressive myelopathy in our study was spinal trauma (50%) followed by spinal infection (28%) [Table 1]. This finding is in coherence with the finding of Kulkarni et al (1987).3
Table 1
Causes of compressive myelopathy
| MR diagnosis | Number of patients (n=50) | % |
| Traumatic Myelopathy | 25 | 50 |
| Infection/TB | 14 | 28 |
| Primary neoplasm | 5 | 10 |
| Secondary Neoplasm/Metastases | 6 | 12 |
Majority of cases in this present study with post-traumatic myelopathy and primary neoplasms were young adults/ middle age group (31-50 years). While patients with infection and metastases belonged to older age group (>50 years). This is in an agreement with the study of Granados A et al. (2011)1 & Yukawa et al(2007)4 [Figure 1].
In this study most of the spinal injury (88%) occur in male population while spinal infection/TB (57.1%), primary neoplasms (60%) were more common in female population while secondary neoplasms were seen equally in both the gender [Figure 2]. This is in comparison to the study conducted by Yang R et al. (2014).5
Figure 3, Figure 4 depict trauma & infectious spondylitis were common causes for extradural compression while primary neoplasms were more common in intradural extramedullary compartment in our study. However, one case of primary neoplasm was in intramedullary compartment.
Table 2
Level of spinal injury
| Level of lesion | Number of patients(n=25) | %* |
| Cervical (C) | 15 | 60 |
| Thoracic(T) | 11 | 44 |
| Thoraco – Lumbar (TL) | 0 | 0 |
| Lumbar(L) | 2 | 8 |
It is obvious from Table 2 that in spinal injuries, the common site involved was the cervical followed by thoracic region probably due to more cases of vehicular accident which is in coherence with the study of Granados A et al. (2011)1 while in contrast with the findings of the study done by Kulkarni et al.3
MRI depicts spinal cord changes (high signal intensity on T2WI and STIR sequence) along with the relationship of subluxed / dislocated vertebral bodies to the cord, posterior elements fracture, ligamentous disruption, hematoma & soft tissue injuries (high signal on STIR). All these have prognostic implication and can be used to classify injury into stable / unstable [Figure 6, Figure 7 ]. Findings of this current study is in agreement with the study of Kulkarni et al.(1987), Dundamadappa SK (2012),6 Flanders et al(1997)7 & warner J et al. (1996)8 which indicate advantage of MRI in demonstrating all these changes[Figure 5].
Figure 1
Pre and paravertebral collection with ALL and PLL disruption with severe cord compression and extensive edema
Figure 2
Odontoid fracture with atlantoaxial subluxation, ligamentous injury with an increased ADI, cord edema and compression
In non-traumatic causes of spinal cord compression epidural soft tissue component is seen in 20 patients (80%) cord changes are seen in 6 patients (24%), pre and paravertebral collection in 13 patients (52%) Ligamentous disruption in 2 patients (8%) posterior elements abnormality in 5 patients (20%) stable fractures in 2 patients (8%) unstable fractures in 1 patients (4%)[Figure 8 ]. MRI in infective spondylitis showed epidural component as hypointense on T1WI, hyperintense on T2WI and FLAIR images and rim enhancement around the intra–osseous and paraspinal soft tissues abscess[Figure 9].
Figure 3
Cervical spine demonstrating tuberculous spondylodiscitis causing cord compression with cold abscess and epidural abscess
Out of 6 patients, 5 (83.3%) showed more than one lesions. This is in comparison to study done by Lien et al. in which 78% had more the one lesions. In our study most common site of involvement(metastasis) was the thoracic spine (83.3%). This is in comparison to the study done by Livingston et al.9 where site of epidural tumor in thoracic spine was 68%. We used T1WI, T2WI and STIR sequence to image spinal metastases. T1WI was useful in the detection of bone marrow metastases and STIR helped in picking up more marrow lesions[Figure 10][Figure 11].
Table 3
Primary neoplasms and their compartmental distribution
| Primary neoplasm (5) | No. of patients |
| Meningioma | 02 |
| Neurofibroma | 02 |
| ependymoma | 01 |
| Primary neoplasm (5) | No. of patients |
| Intradural - extramedullary | 4(80%) |
| Intramedullary | 1(20%) |
Primary neoplasms (80%) were common in the intradural extramedullary compartment in this study[Table 3]. In our study, there were 5 cases of primary neoplasm out of which 2 cases were neurofibroma, 2 cases meningioma and rest one case was of ependymoma. Nerve sheath tumors were iso to hypointense on T1WI and hyperintense on T2WI and showed intense heterogeneous enhancement on post contrast. Out two cases of nerve sheath tumour one was plexiform neurofibromatosis which demonstrated hypointense central focus (target sign) on T2WI [Figure 12] and another was neurofibroma showed extension into neural foramina [Figure 13]. Similar findings can be observed in studies done by Dorsi et al and Matsumo et al.10 Meningioma showed isointensity on T1 & T2WI. On postcontrast study it showed homogenous enhancement which was coherent with the studies done by Matsumoto et al., Genzen et al.11 and Saweidane et al.12 In our study ependymoma which was in cervical region, showed T1iso to hypointensity & T2 iso to hyperintensity. A hypointense hemosiderin rim (cap sign) on T2 weighted images was also observed. Similar finding can be seen in study done by Kahan et al.13
Conclusion & Recommendation
MR imaging depicts the spinal cord directly, assesses its contour and internal signal intensity characteristics reliably and noninvasively so we can evaluate associated cord oedema or contusion and also the integrity & early changes in intervertebral discs and ligaments which can be crucial in long term prognosis of the patient. So, it makes MRI, an essential modality in assessing soft tissues of the spine and spinal cord abnormalities. Thus, MRI is very sensitive imaging modality to detect, characterize, determine the extent of various Spinal tumours and infections. So, we can conclude that MRI is definitive, accurate, though costly but non-invasive, radiation free modality for evaluation of Compressive myelopathy.
Further study could be established to emphasize the role of MRI in determining the severity of cord compression and in evaluating the prognosis. This could be more helpful to determine surgical intervention of needed patients. It can also play a valuable role in triage during disaster, particularly when looking at the patient overload with respect to the patient and infrastructure/resource ratio at our hospitals in India.
Due to lack of quantitative assessment of signal changes in MRI sequences, combination of MRI and 18 F-FDG-PET could be done as future research to uncover more features of compressive myelopathy with respect to prognosis.
