These therapies are associated with dysfunction of the tight endothelial junctions of the blood-brain barrier, leading to vasogenic edema as described above. In addition to edema, these therapies are associated with microhemorrhages in the brain known as ARIA-H. Familiarity with ARIA can aid radiologists and clinicians in determining optimal management for those affected. Posterior reversible encephalopathy syndrome
Posterior reversible encephalopathy syndrome (PRES) is a rare clinical disease characterized by cerebral edema. The exact pathophysiology, or cause, of the syndrome is still debated but is hypothesized to be related to the disruption of the blood-brain barrier. The syndrome features acute neurological symptoms and reversible subcortical vasogenic edema predominantly involving the parieto-occipital areas on MR imaging. PRES in general has a benign course, but PRES-related intracranial hemorrhage has been associated with a poor prognosis. Idiopathic delayed-onset edema
Deep brain stimulation (DBS) is effective treatment for several neurological and psychiatric disorders, most notably Parkinsons disease. DBS is not without risks and although rare, idiopathic delayed-onset edema (IDE) surrounding the DBS leads have been reported. Symptoms can be mild and nonspecific, including reduction of the stimulation effect, and can be confused for other causes of edema. Thus, imaging is recommended to rule out other causes. The condition is generally self-limiting and the exact mechanism of the cause is unexplained. Early identification can help persons affected avoid unnecessary surgical procedures or antibiotic treatments. Massive brain swelling after cranioplasty
Decompressive craniectomy is frequently performed in cases of resistant intracranial hypertension secondary to several neurological conditions and is commonly followed by cranioplasty.
Younger age
Higher severity of symptoms on the National Institutes of Health Stroke Scale
Signs of current ischemia on clinical exam
Decreased level of consciousness
Hyper dense artery sign and larger affected area on CT imaging
Higher blood glucose

Classification
Cerebral edema has been traditional classified into two major sub-types: cytotoxic and vasogenic cerebral edema. This simple classification helps guide medical decision making and treatment of patients affected with cerebral edema. There are, however, several more differentiated types including but not limited to interstitial, osmotic, hydrostatic, and high altitude associated edema. Within one affected person, many individual sub-types can be present simultaneously.The following individual sub-types have been identified:

Cytotoxic
In general, cytotoxic edema is linked to cell death in the brain through excessive cellular swelling. During cerebral ischemia for example, the blood–brain barrier remains intact but decreased blood flow and glucose supply leads to a disruption in cellular metabolism and creation of energy sources, such as adenosine triphosphate (ATP). Exhaustion of energy sources impairs functioning of the sodium and potassium pump in the cell membrane, leading to cellular retention of sodium ions. Accumulation of sodium in the cell causes a rapid uptake of water through osmosis, with subsequent swelling of the cells. The ultimate consequence of cytotoxic edema is the oncotic death of neurons. The swelling of the individual cells of the brain is the main distinguishing characteristic of cytotoxic edema, as opposed to vasogenic edema, wherein the influx of fluid is typically seen in the interstitial space rather than within the cells themselves.