A pictorial review of diseases causing meningeal enhancement in paediatric practice

Meningeal enhancement on contrast enhanced computed tomography (CT) and magnetic resonance imaging (MRI), scans can occur in normal or diseased meninges. Any process that causes meningeal irritation can cause abnormal meningeal enhancement. In certain clinical settings, abnormal meningeal enhancement can add weight to a suspected clinical diagnosis, e.g. tuberculous meningitis. However, in the setting of neoplastic disease, the presence of abnormal meningeal enhancement can imply metastatic involvement of the meninges, which alters patient management, and implies a worse prognosis. With previous surgery for brain parenchymal neoplasm, previous lumbar puncture, previous intrathecal chemotherapy, or craniospinal radiotherapy it is critical to distinguish between iatrogenic meningeal enhancement and metastatic involvement of the meninges. There are characteristics of the enhancement, which can be of assistance in making this differentiation. When abnormal meningeal enhancement is encountered unexpectedly, a differential diagnosis is provided to help elicit the cause.