What are the CT/MRI criteria for diagnosis of acute hydrocephalus?

Updated: Jun 04, 2018
  • Author: Stephen L Nelson, Jr, MD, PhD, FAACPDM, FAAN, FAAP; Chief Editor: Jasvinder Chawla, MD, MBA  more...
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CT/MRI criteria for acute hydrocephalus include the following:

  • Size of both temporal horns is greater than 2 mm, clearly visible. In the absence of hydrocephalus, the temporal horns should be barely visible.

  • Ratio of the largest width of the frontal horns to maximal biparietal diameter (ie, Evans ratio) is greater than 30% in hydrocephalus.

  • Transependymal exudate is translated on images as periventricular hypoattenuation (CT) or hyperintensity (MRI T2-weighted and fluid-attenuated inversion recovery [FLAIR] sequences).

  • Ballooning of frontal horns of lateral ventricles and third ventricle (ie, "Mickey mouse" ventricles) may indicate aqueductal obstruction.

  • Upward bowing of the corpus callosum on sagittal MRI suggests acute hydrocephalus.

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