USZ / NRA Imaging of Spinal Stroke Institute of Neuroradiology, University of Zurich, Switzerland

USZ / NRA Spinal cord infarction: frequency l not established, large clinical investigations are lacking l ~1% of all strokes, annual incidence of 12 in 100,000 l occurrence rate at death: 0.23% (9/3784) autopsies » small arterial vessels with low flow rates » extensive collateral network between the main medullary arteries at the spinal cord surface medullary arteries at the spinal cord surface

USZ / NRA Arteries supplying the spinal cord Novy, J. et al. Arch Neurol 2006;63: Lazorthes, G. et al. Rev Neurol 1966;115: T3 T8

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Spinal cord infarction: clinical symptoms l acute onset, severe back pain l bilateral weakness, paresthesias and sensory loss l loss of sphincter control evident within a few hours »confounding diagnoses (acute transverse myelopathy, viral myelitis, Guillain-Barré, mass lesions), develop over h with slower evolution, rarely painful »epidural/subdural hematomas need exclusion by MRI l symptoms and degree of deficits depend on the affected level and size of the vascular territories

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Spinal cord infarction: etiology Classification according to location of vascular pathology – intrinsic cord vessels: arteritis (SLE, granulomatous), emboli of atheroma, disc compression emboli of atheroma, disc compression – ASA occlusion: arteritis, trauma, spondylosis, adhesive arachnoiditis, spinal DSA, anesthesia arachnoiditis, spinal DSA, anesthesia – aortic disease: dissecting aneurysm, surgery, aortic thrombosis, atherosclerotic embolization thrombosis, atherosclerotic embolization – uncommon causes: decompression sickness, circulatory failure (cardiac arrest, hypotension) failure (cardiac arrest, hypotension) – : – no identifiable cause: 50-75% of cases

USZ / NRA Spinal cord infarction: pathogenesis a) mechanical triggering factor: - anterior, posterior - unilateral or bilateral coincides with the level of the involved radicular artery b) hypoperfusion factor: - central and transverse involve several levels in the thoracolumbar region Novy, J. et al. Arch Neurol 2006;63:

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Imaging of spinal cord infarction: MRI – T2-w imaging not sensitive in the first hours after symptoms onset (abnormal signal in 45%-67%) symptoms onset (abnormal signal in 45%-67%) – “snake-eyes” on axial T2-w images indicate involvement of the ventral gray matter involvement of the ventral gray matter – contrast enhancement in the subacute stage – hemorrhagic transformation seen as hyperintense signal on the T1-weighted images. on the T1-weighted images.

USZ / NRA ● ●The gray matter is predominantly affected due to its high vulnerability to anoxia ● ●Motorneurons lose electrophysiological reflex responses 1.5 times faster as interneurons and 3 times faster as dorsal column neurons ● ●terminal ischemia (failure of conduction) occurs after 20 minutes of asphyxia ● ●abrupt anoxia shortens the survival time of all structures Vulnerability of spinal cord to anoxia Gelfan S, Tarlov IM. J Neurophysiol 1955;18:

USZ / NRA Th4 70 y, history aortic dissection, status after grafting, hypertension, coronary artery disease presents with acute paraplegia.

USZ / NRA DW-MRI of the spinal cord Challenges: l fine structure and elasticity of the SC l requirement for high in-plane resolution l Artifacts related to motion – CSF pulsations – respiratory motion – swallowing l Spatially rapid changes in susceptibility

USZ / NRA Imaging of spinal cord infarction: DW-MRI l demonstration of intracelullar, cytotoxic edema l diffusion abnormality reported 4-30 h following onset, always in the presence of T2-w signal abnormality l decrease (75%) of the calculated ADC values l in follow-up performed 5-20 d following infarction, early normalization of ADC with persistent T2-w abnormality

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26-year-old man left-sided neck pain, acute onset lower limb weakness and difficulty voiding.

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2 w follow-up2 m follow-up Zhang J., et al. J Spinal Disord Tech. 2005; 18:

USZ / NRA Zhang J, et a. JMRI 2007;26:

USZ / NRA Spinal cord infarction l Prognosis and outcome – substantial motor, sensory, bladder and bowel dysfunction – short-term mortality rate 20-25% – vascular, infectious and other medical complications – long term prognosis is determined by the degree of cord sparing (unilateral infarcts have better prognosis) sparing (unilateral infarcts have better prognosis) – early diagnosis may contribute to improved patient management management

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