Pachymeningeal enhancement

Background

• MRI finding suggestive of meningitis
• Also known as dura-arachnoid enhancement
• Refers to MRI enhancement of the dura and outer layer of arachnoid following contrast enhancement

Differential Diagnosis

• Meningitis, including bacterial, viral, fungal, and tuberculous, though they are more likely to present with leptomeningeal enhancement
• Intracranial neoplasms
  • Extra-axial: meningioma and calvarial lesions, which typically show focal pachymeningeal enhancement
  • Intra-axial: primary CNS malignancy amd metastases, which show varied pachymeningeal and leptomeningeal enhancement
• Intracranial hypotension: typically demonstrates diffuse, smooth, wave-like pattern of enhancement in the temporal and frontal base
• Post-procedural or post-operative changes, particularly following craniotomy, intrathecal infusions, shunt placement, or lumbar puncture, which typically shows diffuse, smooth, enhancement, sometimes limited to the side of the procedure
• Idiopathic pachymeningitis
• Cerebral venous thrombosis
• Neurosarcoidosis
• Vogt-Koyanagi-Harada syndrome
• Extramedullary hematopoiesis
• Rheumatoid arthritis
• Granulomatosis with polyangiitis

Further Reading

• Pachymeningeal enhancement-a comprehensive review of literature. Neurosurg Rev. 2015;38(4):649-59. doi: 10.1007/s10143-015-0646-y