Specific Imaging Findings

In patients with ventriculitis CT may show hydrocephalus, while characteristic dependent layering of debris is seen with pyogenic ventriculitis. The debris is of higher attenuation than the CSF and its margin may be indistinct and irregular. Post-contrast CT images may show linear enhancement along the ventricular walls. Ventricular debris, ventriculomegaly, periventricular T2 hyperintensity, and ependymal contrast enhancement are the signs of ventriculitis on MR imaging. Similar to CT, the ventricular debris is seen as dependent layering material with higher signal intensity than the CSF on FLAIR and T1WI. The material characteristically shows irregular and undulating interface with the CSF, unlike the typical straight horizontal fluid-fluid levels. The purulent intraventricular material is very bright on DWI with corresponding low ADC values. Ependymal and periventricular edema is best seen on FLAIR images as linear hyperintensity lining the affected ventricles. DWI/ADC and FLAIR images are more sensitive for detection of pyogenic ventriculitis than post-contrast T1WI. However, in cases of non-pyogenic ventriculitis, there is usually no ventricular debris so that ependymal enhancement and hyperintensity on FLAIR images may be the only imaging findings.

Pertinent Clinical Information

Pyogenic ventriculitis is an uncommon but often severe and life-threatening intracranial infection. It is a relatively frequent complication of neonatal meningitis, but rare with adult purulent meningitis, most commonly occuring when an abscess ruptures into the ventricles. Clinical features of ventriculitis are often obscure and nonspecific as it typically occurs in already critically ill patients. Early detection is essential for prompt treatment, which is crucial for these patients, as devastating neurological damage can occur with delayed treatment, even if the infection is ultimately eradicated. High doses of systemic antibiotics may be combined with ventricular drainage and intraventricular administration of antibiotics.