|Year : 1999 | Volume
| Issue : 4 | Page : 290--3
Acute transverse myelitis : MR characteristics.
JM Murthy, JJ Reddy, AK Meena, S Kaul
Departments of Neurology and Radiology, Nizam's Institute of Medical Sciences, Panjagutta, Hyderabad, 500082, India., India
J M Murthy
Departments of Neurology and Radiology, Nizam«SQ»s Institute of Medical Sciences, Panjagutta, Hyderabad, 500082, India.
Magnetic resonance imaging findings in 13 patients with acute transverse myelitis are reviewed. In 12 cases centrally located high intensity signal extending over few spinal segments was noted. The lesion occupied more than two thirds of the cord«SQ»s cross-sectional area in 8 patients. Central dot sign was noted in 7 patients. Variable cord enlargement was seen in 5 patients. Contrast study in one patient showed peripheral enhancement. The MR characteristics that help in differentiating transverse myelitis from spinal form of multiple sclerosis are discussed.
|How to cite this article:|
Murthy J M, Reddy J J, Meena A K, Kaul S. Acute transverse myelitis : MR characteristics. Neurol India 1999;47:290-3
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Murthy J M, Reddy J J, Meena A K, Kaul S. Acute transverse myelitis : MR characteristics. Neurol India [serial online] 1999 [cited 2023 Jan 28 ];47:290-3
Available from: https://www.neurologyindia.com/text.asp?1999/47/4/290/1587
Acute transverse myelitis (ATM) is an uncommon syndrome and is characterized by bilateral motor, sensory, and autonomic dysfunctions resulting from the involvement of both halves of the spinal cord in the absence of pre-existing neurologic or systemic disease., The reported annual incidence was 1.34 per million population. Magnetic resonance imaging (MRI) is the premier modality of investigation in the diagnosis of acute transverse myelitis and also in differentiating this entity from spinal form of multiple sclerosis and cord tumours. This report presents MR characteristics in 13 patients with ATM.
The MR studies of 13 patients with clinically proven acute transverse myelitis were reviewed retrospectively. Criteria for the diagnosis of ATM included : 1) acutely developed paraparesis or quadriparesis affecting motor and sensory systems as well as sphincters, and 2) absence of involvement of other parts of nervous system clinically, electrodiagnostically and/or on neuroimaging i.e. MRI.
MRI was obtained during peak symptoms and was performed on the 0.3 T Fonar electromagnet system or 0.5 T superconducting magnet and spin echo (SE) sequences were obtained. On the 0.3 T unit Tl weighted images were obtained at TR 500-600 ms and TE 30 ms and T2 weighted images at TR 2000 ms and TE 85 ms. The studies performed on the 0.5 T system included TI weighted using TR 600-700 ms, TE 15 ms and T2 weighted sequences at TR 2200 ms and TE 20-80 ms. Contrast study was done in one patient.
The study group consisted of 8 males and 5 females whose age ranged from 10 years to 46 years. The antecedent event was nonspecific infection of upper respiratory tract in 6 patients and it followed sample antirabies vaccination in one patient. Nine patients presented with cervical myelopathy, one with cervicodorsal myelopathy and 3 with dorsal myelopathy [Table I].
High signal intensity was the feature in 12 patients and one patient showed mild swelling of the cord with no signal alteration. The lesion extended over 3 or more segments in all the patients [Figure 1]. Coronal sections clearly showed asymmetrical nature of the lesion [Figure 2]. The high signal intensity on axial T2 weighted images was centrally located in all the patients and occupied more than two thirds of the cross sectional area of the cord in 8 patients. Central dot sign, a small dot, isointense with the cord was seen in 7 of the 8 patients who had a large area of central hyperintensity [Figure 3]. Variable, mild to moderate cord expansion was observed in 6 patients. Contrast study in one patient showed peripheral enhancement of the lesion [Figure 4].
Acute transverse myelitis, a fragment of disseminated vasculomyelinopathy, is pathogenetically identical with acute disseminated encephalomyelitis., The hallmark lesion in ATM is perivenular inflammation and surrounding demyelination., Magnetic resonance imaging is the premier modality of investigation to delineate such lesions in the cord.,,
In the literature, MR findings of ATM have been described for a small number of patients and the largest number (fifteen patients) was reported by Choi et al. Reports of MR imaging findings in patients with ATM have described local enlargement of the spinal cord and increased signal intensity on long repetition time/echo time sequences., Scans done early in the course of the disease may not show any signal intensity on T2 weighted images. Like others, we found high signal intensity extending over several spinal segments. Commonly, three to four segments were involved. Barakos et al reported signal abnormality extending over at least six spinal segments. Recently, Misra and colleagues have described unusual cases of ATM with long segment involvement (cervical to conus). Multiple sclerosis plaques, on the other hand, are usually less than two vertebral segments in length.
In our series and the series reported by Choi et al, in a significant number of cases, the centrally located high signal intensity occupied more than two thirds of the cross-sectional area of the cord. In multiple sclerosis, plaques are usually located peripherally and occupy less than half the cross-sectional area of the cord. The central isointensity, or dot, represents central gray matter squeezed by the uniform, evenly distributed oedamatous changes of the cord. Choi and colleagues have demonstrated the role of contrast media in differentiating transverse myelitis from multiple sclerosis. In transverse myelitis, enhancement is in the periphery of a centrally located area of high T2 weighted images. In multiple sclerosis, the lesions show enhancement in the central zone of peripherally located high signal intensity on T2 weighted images.,
In conclusion, certain MRI characteristics help in differentiating acute transverse myelitis from spinal form of multiple sclerosis. These include: 1) centrally located high intensity signal extending over 3 to 4 segments and occupying more than two thirds of the cord cross-sectional area and 2) peripheral contrast enhancement of high intensity signal.
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