Hyperdense Middle Cerebral Artery in a Boy with Road Traffic Accident

A 6-year-old, right-handed boy presented with acute onset encephalopathy, seizure, and right hemiparesis following a road traffic accident. A non-contrast computed tomography (CT) of the head ([Fig. 1]) showed a hypodensity at the left basal ganglia and a hyperdense middle cerebral artery (MCA). A magnetic resonance imaging (MRI) of the brain showed a left basal ganglia infract, and the MR angiography showed attenuated left MCA ([Fig. 2]). The “hyperdense left MCA sign” (HMCAS) was secondary to a post traumatic dissection and the resulting thrombosis. The child was managed with anticoagulant therapy.

Fig. 1 Axial non-contrast CT head (A) at the level of basal cistern showing hyperdense left middle cerebral artery (M1 segment [vertical arrow]). (B) Showing left basal ganglia hypodensity and curvilinear hyperdensity in the Sylvian fissure suggestive of subarachnoid hemorhage (horizontal arrow). CT, computed tomography.

Fig. 2 Axial T2-weighted MRI (A) shows loss of left MCA flow void with intraluminal hyperintensity (red arrow) and hyperintensity (black arrow) in axial T1-weighted (B) suggestive of thrombosis. Axial T2-weighted MRI showing hyperintensity at the left basal ganglia and the left periventricular white matter (C) and MR angiography showing attenuation of left MCA at its origin and M1 segment (D). MCA, middle cerebral artery; MRI, magnetic resonance imaging.

The incidence of stroke after trauma is low, seen in 0.004% of all cases of trauma. Almost half of post-trauma stroke are due to dissection.[1] An area of increased attenuation along the first and second segment of MCA compared with the contralateral hemisphere on non-contrast CT is described as HMCAS.[2] It is one of the earliest signs of ischemic stroke and presents within 90 minutes of onset of neurological symptoms.[3] The hyperattenuating component represents an intraluminal clot due to localized thrombus or an embolus. The American Stroke Association recommends oral anticoagulation for 3 to 6 months for cervicocephalic arterial dissection.[4] The role of thrombolysis in dissection and stroke in children is still controversial. Intracranial dissection is a contraindication for thrombolysis in pediatric stroke.[5] However; anecdotal cases of pediatric arterioischemic stroke with extracranial dissection presenting within the stroke window have been treated with thrombolysis.[6]

Authors' Contributions

Sumeet Dhawan conceptualized the case and wrote the initial draft of manuscript. Abhinandan Sood and Naveen Sankhyan edited the initial draft of manuscript and did patient management and review of literature. Sameer Vyas analyzed the radiology and revised the manuscript. Renu Suthar critically reviewed manuscript for important intellectual content and final approval of the version to be published.

Disclosure

The authors report no disclosures relevant to the manuscript.

• References

• 1 Fox CK, Hills NK, Vinson DR. , et al. Population-based study of ischemic stroke risk after trauma in children and young adults. Neurology 2017; 89 (23) 2310-2316
• 2 Tomsick TA, Brott TG, Chambers AA. , et al. Hyperdense middle cerebral artery sign on CT: efficacy in detecting middle cerebral artery thrombosis. AJNR Am J Neuroradiol 1990; 11 (03) 473-477
• 3 Krings T, Noelchen D, Mull M. , et al. The hyperdense posterior cerebral artery sign: a computed tomography marker of acute ischemia in the posterior cerebral artery territory. Stroke 2006; 37 (02) 399-403
• 4 Roach ES, Golomb MR, Adams R. , et al; American Heart Association Stroke Council; Council on Cardiovascular Disease in the Young. Management of stroke in infants and children: a scientific statement from a Special Writing Group of the American Heart Association Stroke Council and the Council on Cardiovascular Disease in the Young. Stroke 2008; 39 (09) 2644-2691
• 5 Stroke in childhood - clinical guideline for diagnosis, management and rehabilitation. 2017; https://www.rcpch.ac.uk/resources/stroke-childhood-clinical-guideline-diagnosis-management-rehabilitation . Accessed on July 26, 2018
• 6 Satti S, Chen J, Sivapatham T, Jayaraman M, Orbach D. Mechanical thrombectomy for pediatric acute ischemic stroke: review of the literature. J Neurointerv Surg 2017; 9 (08) 732-737