Table 2.

Classification of CCM by MRI and Histopathology

Lesion	MR Signal	Histopathology
Type 1	SE T1: Hyperintense core	Subacute hemorrhage, surrounding rim of hemosiderin-laden macrophages
	SE T2: Hyperintense core or hypointense core
Type 2	Most common type-classic popcorn lesion	Lesions with loculated hemorrhages and thromboses of varying ages enveloped by gliotic tissue, hemosiderin rim
	SE T1: Mixed signal intensity centrally
	SE T2: Mixed signal intensity centrally with surrounding hypointense/low signal rim with blooming
Type 3	SE T1: Hypointense to isointense centrally	Chronic resolved hemorrhage with hemosiderin staining in and around lesion
	SE T2: Hypointense lesion with hypointense rim with blooming/magnifying size of lesion
Type 4	SE T1: Not seen or difficult to identify	Multiple punctate microhemorrhages
	SE T2: Not seen or difficult to identify	Tiny CCM or telangiectasia
	T2* GRE: Punctate hypointense lesions, black dots with blooming	Small areas of hemosiderin deposition or possibly intravascular blood within telangiectasias or other small lesions
	SWI: Punctuate hypointense lesion (more sensitive than GRE)

CCM indicates cerebral cavernous malformation; GRE, gradient recalled echo; MRI, magnetic resonance imaging; SE, spin echo MRI; and SWI, susceptibility-weighted imaging. Adapted and modified from Zabramski et al³² with permission.