Neuroimaging in Intracerebral Hemorrhage
Intracerebral hemorrhage (ICH) is described as spontaneous extravasation of blood into the brain parenchyma. This clinical entity is present in 10% to 15% of all stroke cases1 in the Western population, with reported incidence rates higher in Asia.2–4 It is also associated with a higher mortality rate compared with either ischemic stroke (IS) or subarachnoid hemorrhage.5
ICH is classified according to its primary (80% to 85%) or secondary (15% to 20%) causes. More than 50% of primary ICH events are directly correlated with hypertension as a risk factor, whereas ≈30% are known to be associated with cerebral amyloid angiopathy (CAA). The causes of secondary ICH include hemorrhage conversion of IS, amyloid angiopathy, stimulant drugs, vascular malformations (aneurysms, arterovenous malformations, venous angioma, cavernoma, dural arteriovenous fistula), coagulopathy (hereditary, acquired, induced by anticoagulants or antiplatelets), neoplasms, trauma, vasculitis, Moyamoya disease, or sinus venous thrombosis (Table 1).
Currently, ICH is classified as either primary or secondary according to only causes. However, this classification does not take into account the inherent differences of underlying vascular pathologies. Hence, a more systematic stratification based on new criteria is currently being developed.1 Specifically, Meretoja et al6 have proposed the SMASH-U classification, based on the underlying diseases of ICH: Structural lesions (cavernomas and arterovenous malformations), Medication (anticoagulation), Amyloid angiopathy, Systemic diseases (liver cirrhosis, thrombocytopenia, and various rare conditions), Hypertension, and Undetermined causes. This classification has proven to be feasible and is also associated with survival prognosis.6 Another classification used in clinical practice distinguishes between deep and lobar ICHs according to location. Deep ICHs are located in the basal ganglia, thalamus, internal capsule, cerebellum, or brain stem and are generally related to hypertension. Whereas, lobar ICHs usually require more extensive diagnostic testing because …