Table 1.

Definitions of brain abnormalities

Brain Abnormality*	Definition
Acute Ischemic Changes	Any acute ischemia and infract seen in the brain based on diffusion weighted imaging trace maps and apparent diffusion coefficient maps
PVL	Lesions with typical appearance and location of periventricular leukomalacia, including punctate white matter injury
Nonacute Ischemic T2 Changes	Focal lesions without acute ischemic findings that are likely to be result of prior ischemia based on imaging appearance and which follow vascular territories
Delayed Myelination	Assessment of myelination based on well established norms of myelination progression on the basis of T1-weighted and T2-weighted images
Developmental Defect (Malformation)	Any congenital malformation of the brain
Generalized Atrophy	Diffuse volume loss in the brain
Focal Tissue Loss & Atrophy	Any non-diffuse focal loss and atrophy of brain parenchymal tissue
Ventriculomegaly	Enlargement of the ventricles due to any cause; may or may not be associated with generalized volume loss
Intracranial hemorrhage – gross (acute or chronic)	Detection of gross brain parenchymal or extra-axial hemorrhage, acute or chronic, based on any combination of imaging sequences
Intraventricular Hemorrhage	Presence of any new or old intraventricular hemorrhage
Operculum	Whether the Sylvian operculum remains widely open or has normally closed
SWI Veins	Presence or absence of abnormal prominence of the cortical and medullary veins based on susceptibility weighted imaging maximum intensity projection images
Choroid Plexus Susceptibility	Presence or absence of susceptibility in either choroids plexus on susceptibility weighted imaging

^*Note that while these classifiers are distinct, there may often be overlap in some of the features for a particular lesion or patient.