May Be Caused by

 Common

Avascular meningioma

Cerebral infarction

Cortical atrophy

Epidural empyema

Epidural hematoma

Epidural hygroma

Occlusive vascular disease

Steal phenomenon

Subdural empyema

Subdural hematoma

Subdural hygroma

 Uncommon

Arachnoid cyst

Epidermoid

Langerhans cell histiocytosis

Metastasis

Normal large subarachnoid space

Parasitic cyst

Porencephalic cyst

Sarcoma

Syphilitic pachymeningitis

Tuberculoma