Ependymal enhancement
Some overlap with periventricular enhancement. Ependymal enhancement often heralds a serious condition 1).
Main DDx is tumor vs. infectious process.
1. ventriculitis or ependymitis: ependymal enhancement occurs in 64% of cases of pyogenic ventriculitis 2).
a) infection may occur in the following settings
● following shunt surgery
● after intraventricular surgery
● with indwelling prosthetic devices (e.g. Ommaya reservoir)
● with use of intrathecal chemotherapy
● with meningitis
● with viral ependymitis
● in some cases of CMV encephalitis in immunocompromised patients
● granulomatous involvement: esp. in immunocompromised patients; e.g. tuberculosis, mycobacterium, syphilis
b) infections may be 3).
● bacterial (pyogenic) ventriculitis
● tuberculous ventriculitis
● cystic lesions suggest cysticercosis
2. carcinomatous meningitis: typically also produces meningeal enhancement
3. multiple sclerosis: usually more periventricular (in the white matter)
4. tumors
a) lymphoproliferative disorders
● CNS lymphoma
● leukemia
b) ependymoma
● with tumor spread
● transient enhancement reported in a child with ependymoma in the absence of tumor spread 4)
c) metastasis
d) germ cell tumors
5. tuberous sclerosis: subependymal hamartomas appear as nodules that occasionally enhance. These gradually calcify with age
6. in the presence of appropriate constitutional symptoms: rare causes of linear enhancement
include: neurosarcoidosis, Whipple’s disease, metastatic multiple myeloma (usually nodular)
In immunocompromised patients, the enhancement pattern may help distinguish between the following (which tend to occur in this population 5) ):
1. thin linear enhancement: suggests virus (CMV or varicella-zoster)
2. nodular enhancement: suggests CNS lymphoma
3. band enhancement: less specific (may occur with virus, lymphoma, or tuberculosis (TB).