Table 1. MRI features-based types of cerebral CMs and histopathologic correlation ¹⁹ .

Type	MRI signals			Histopathology
	T1-weighted signal intensity	T2-weighted signal intensity	Signal intensity on SWI or T2 gradient echo sequence
I	Hyperintense	Heterogeneous signals with a hypointense rim	Hypointense	Subacute hemorrhage surrounded by hemosiderin stain macrophages and gliotic brain
II	Heterogenous with classic “popcorn” appearance	Heterogenous with classic “popcorn” appearance	Hypointense	Loculated areas of hemorrhage and thrombosis of varying age surrounded by hemosiderin-stained brain and gliosis
III	Hypointense and isointense	Hypointense and isointense	Hypointense	Chronic resolved hemorrhage with hemosiderin staining within and around the lesion
IV	Poorly seen tiny, often multiple, punctate foci with low signals	Poorly seen tiny, often multiple, punctate foci with low signals	Hypointense	Multiple areas of hemosiderin deposition without a central core

Abbreviations: CM cavernous malformation; MRI magnetic resonance imaging; SWI susceptibility-weighted imaging.