IMAGES IN NEUROLOGY
|Year : 2017 | Volume
| Issue : 3 | Page : 319
Susceptibility-weighted imaging torch fire sign in a patient with dystonia due to hypoxic-ischemic injury
Savith Kumar, Chandrasekharan Kesavadas, Bejoy Thomas
Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
|Date of Web Publication||10-Aug-2017|
Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Medical College PO, Trivandrum - 695 011, Kerala
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Kumar S, Kesavadas C, Thomas B. Susceptibility-weighted imaging torch fire sign in a patient with dystonia due to hypoxic-ischemic injury. Ann Indian Acad Neurol 2017;20:319
|How to cite this URL:|
Kumar S, Kesavadas C, Thomas B. Susceptibility-weighted imaging torch fire sign in a patient with dystonia due to hypoxic-ischemic injury. Ann Indian Acad Neurol [serial online] 2017 [cited 2019 Dec 8];20:319. Available from: http://www.annalsofian.org/text.asp?2017/20/3/319/212726
A 39-year-old male presented with dystonia since 2010 involving both upper and lower limbs. He had undergone mitral valve replacement in the past (2009) for rheumatic heart disease with severe mitral stenosis. During the postoperative period, there was difficulty in weaning the patient from the ventilator. The patient developed ischemic acute tubular necrosis and hypoxic encephalopathy. Magnetic resonance imaging (MRI) of the brain done [Figure 1] as a part of the evaluation for dystonia in 2016 showed atrophy of the bilateral posteromedial putamen and mineralization on susceptibility-weighted imaging (SWI) [Figure 1]c and [Figure 1]d with relative normal signal intensity of the basal ganglia on fluid-attenuated inversion recovery (FLAIR) and T1-weighted images [Figure 1]a and [Figure 1]b.
|Figure 1: (a) Axial fluid-attenuation inversion recovery (left), (b) T1 (right) images of the brain reveal normal signal intensity of the basal ganglia. (c) Susceptibility-weighted imaging (left) (d) phase image (right) of the brain reveals atrophy of the posteromedial putamen and blooming, appearing-like torch fire|
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There are diverse patterns of hypoxia-related brain injury which depends on the severity of hypoxia and maturation of the brain. In an adult, the posterior putamen, ventrolateral thalami, cerebral cortex (sensory motor and visual cortex), cerebellum, and hippocampi are sites which are most vulnerable to severe asphyxia. The selective vulnerability of these areas is due to the presence of postsynaptic glutamate receptors, which are in turn susceptible to glutamate excitotoxicity., On imaging with MRI during the chronic stage, the involved areas appear hyperintense on T2 and FLAIR due to atrophy and gliosis. The posteromedial putaminal atrophy and gliosis on FLAIR resemble a torch fire with the posterior putamen constituting the handle, the rest of the putamen the flame and this appearance was described as torch fire sign by Thomas et al. Our case shows a similar appearance of putamen on SWI with FLAIR showing a relatively normal signal intensity. SWI is sensitive in picking up the subtle deposition of paramagnetic substance or blood product in the infarcted tissue and also outlining the involved posterior putamen suggesting the etiology for dystonia which is due to hypoxic injury based on the typical imaging appearance.
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| References|| |
Huang BY, Castillo M. Hypoxic-ischemic brain injury: Imaging findings from birth to adulthood. Radiographics 2008;28:417-39.
Thomas B, Krishnamoorthy TH, Kapilamoorthy TR. 'Torch fire sign': A new MR sign in profound hypoxic ischemic brain injury in a term infant. Neuroradiol J 2007;20:41-2.