In CT scan,<unk>  will have same density as the normal CSF. Meanwhile, in MRI,<unk>  will have same intensity with CSF. If iodinated contrast is administered during CT scan, the<unk>  will produce high density because of the contrast at 120 kVp. However, at 190 kVp,<unk>  with contrast will have intermediate density. In the majority of cases, if there has not been any acute trauma or severe neurologic symptoms, a small<unk>  on the head CT scan will be an incidental finding. If there is an associated localized mass effect that may explain the clinical symptoms, or concern for a potential chronic SDH that could rebleed, then an MRI, with or without neurologic consultation, may be useful. It is not uncommon for chronic<unk>  hematomas (SDHs) on CT reports for scans of the head to be misinterpreted as<unk> s, and vice versa. Magnetic resonance imaging (MRI) should be done to differentiate a chronic SDH from a<unk> , when clinically warranted. Elderly patients with marked cerebral atrophy, and secondary widened subarachnoid CSF spaces, can also cause confusion on CT. To distinguish chronic<unk> s from simple brain atrophy and CSF space expansion, a gadolinium-enhanced MRI can be performed. Visualization of cortical veins traversing the collection favors a widened subarachnoid space as seen in brain atrophy, whereas<unk> s will displace the cortex and cortical veins. Treatment== Most<unk> s that are asymptomatic do not require any treatment. Some might opt to perform a simple burr-holes to alleviate intracranial pressure (ICP). Occasionally a temporary drain is placed for 24-48 hours post op. In recurrent cases a craniotomy may be performed to attempt to locate the location of the CSF Leak. In certain cases a shunt can be placed for additional drainage. Great caution is used when choosing to look for the CSF leak due to them generally being difficult to spot.
Subdural hygroma
Cystic hygroma
Arachnoid cyst
Dandy–Walker malformation
Subependymoma
Choroid plexus cyst
Encephalocele
Porencephaly