MRI findings of spine: acute flaccid paralysis associated with enterovirus 71 infected hand-foot-mouth disease

Objective: To investigate the characteristics of spinal MR images in acute flaccid paralysis (AFP) associated with enterovirus 71 infected hand-foot-mouth disease. Methods: The spinal MR images of eight infants with AFP and positive EV71 cultures were analyzed during an outbreak of hand-foot-mouth disease in China in 2008. Results: Acute paralysis was observed in one lower limb in 4 of the 8 patients, in four limbs in 2 patients, in one upper limb and both lower limbs in 1 patient, 2 of the 8 patients also had brain stem encephalitis. Lesions were identified in anterior horn regions of spinal cord with hyperintensity on T2-weighted images and hypointensity on T1-weighted images. Location of the lesions included C3 to C7 (1 case), T10 extending to conus medullaris (5 cases) and a combination of the above (2 cases). Five of the 8 patients presented with unilateral paralysis. Two of the 5 cases showed unilateral hyperintense lesions in anterior horn regions and the remaining 3 cases showed bilateral hyperintense lesions in anterior horn regions with a unilateral predominance. One of the 3 patients with bilateral lesions showed slight enhancement of anterior horn with prominent enhancement of ventral roots after intravenous injections of contrast medium. Three of the 8 patients with bilateral paralysis showed bilateral hyperintensity in both anterior horn regions. Conclusion: MR is the imaging modality of choice for the detection of radiculomyelitis of AFP associated with EV71 infection. (authors)