Its epidemiology is varied and depends on the underlying cause.
Meningitis is the most common underlying condition responsible for the ventriculitis. It is directly related to lower host immunity and higher virulence of the causative organism. The occurrence of direct haematogenous spread to the choroid plexus has also been suggested. In long standing cases (>2 months) ventricular septations develop which result in compartmentalization and multiloculated hydrocephalus hydrocephalus and makes prognosis worse.
Non-contrast CT of the brain usually demonstrates only non-specific features, most frequently hyperdense layering material may be seen dependently, particularly in the occipital horns of the lateral ventricles 1.
Hydrocephalus and periventricular low density (which probably represents reactive oedema rather than transependymal oedema related to hydrocephalus 1) is also frequently present, as of course may the features of the underlying abnormality (e.g. meningitis, shunt/EVD, trauma)
Following administration of contrast, thin regular enhancement of the ependymal lining of the ventricles may be seen.
MRI demonstrates the same features as CT, with layering debris in the occipital horns frequently seen. There often an intense restricted diffusion of these intraventricular debris, as seen in the center of a brain abscess.
MRI is also more sensitive to the often subtle periventricular abnormal signal (high T2) and thin contrast enhancement.
Additionally, the periventricular region may demonstrate restricted diffusion on DWI / ADC.
The main differential diagnosis is that of ependymal lining enhancement, which includes ependymal spreading of glioblastoma or primary CNS lymphoma. In these cases, the enhancement is, usually, bumpy/nodular. Extracranial neoplasm metastases and germinoma may also be responsible for similar findings.
- 1. Fukui MB, Williams RL, Mudigonda S. CT and MR imaging features of pyogenic ventriculitis. AJNR Am J Neuroradiol. 2001;22 (8): 1510-6. AJNR Am J Neuroradiol (full text) - Pubmed citation
- 2. Fujikawa A, Tsuchiya K, Honya K et-al. Comparison of MRI sequences to detect ventriculitis. AJR Am J Roentgenol. 2006;187 (4): 1048-53. doi:10.2214/AJR.04.1923 - Pubmed citation