Effaced Sulci, Focal
Anne G. Osborn, MD, FACR
DIFFERENTIAL DIAGNOSIS
Common
Cortical Contusion
Cerebral Ischemia-Infarction, Acute
Spontaneous Intracranial Hemorrhage
Subdural Hematoma
Epidural Hematoma
Neurocysticercosis
Less Common
Primary CNS Neoplasm
Meningioma
Oligodendroglioma
Ganglioglioma
Diffuse Astrocytoma, Low Grade
DNET
Pleomorphic Xanthoastrocytoma
Metastases, Parenchymal
Metastases, Skull and Meningeal
Abscess
Meningitis
Focal Cortical Dysplasia
Tuberous Sclerosis Complex
Thrombosed Cortical Vein(s)
Rare but Important
Extra-Axial Empyema
Meningioangiomatosis
Superficial Siderosis
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Focal = one or several sulci (not hemisphere or whole brain)
Key concept: Is sulcal effacement caused by lesion within sulcus itself or underlying gyrus?
Intra- vs. extra-axial causes
Parenchymal > > sulcal disease
Imaging
Sulcal, gyral masses can be isodense on NECT, isointense on T1-weighted MR → difficult to detect!!
CECT, T2WI, FLAIR, T1 C+ scans most helpful
Helpful Clues for Common Diagnoses
Cortical Contusion
History of closed head injury
Heterogeneous hyper-/hypodense swollen gyri
Look for focal traumatic SAH adjacent to contusions
Cerebral Ischemia-Infarction, Acute
Cortical branch occlusion → gyral swelling
Difficult to see on NECT, T1/T2WI
DWI helps distinguish ischemia (restricts) from neoplasm (usually doesn’t)
Spontaneous Intracranial Hemorrhage
Children/young adult
Vascular malformation, venous occlusion, drug abuse
Middle-aged, older adults
Amyloid angiopathy, hypertension
Hemorrhagic neoplasm (metastasis, GBM)
Subdural Hematoma
Usually crescentic, spreads over hemisphere → more generalized sulcal effacement
Occasionally focal, mimics EDH
Epidural Hematoma
Focal, biconvex extra-axial hematoma
Severe compression of underlying sulci
Mimics: Plasmacytoma, extra-medullary hematopoiesis, etc.
Neurocysticercosis
NCC cysts typically in subarachnoid spaces, depths of sulci
Intense pial inflammatory reaction may efface sulci
Helpful Clues for Less Common Diagnoses
Primary CNS Neoplasms
Any cortical, subcortical neoplasm causes local mass effect, expanded parenchyma/compressed sulci
Age, history helpful
Child, young adult with longstanding seizures: Ganglioglioma (cyst, Ca++ common), DNET (“bubbly” appearance), low grade astrocytoma
Adult: Meningioma (dural-based, often Ca++), oligodendroglioma (Ca++ common, variable enhancement), PXA (look for “dural tail”)
Metastases, Parenchymal
May cause focal mass, variable edema
Almost always enhances
Metastases, Skull and Meningeal
Dural-based, usually isodense/isointense with brain
Look for skull lesions
Abscess
Gray-white junction common site
Early stage (cerebritis) typically does not enhance
Late cerebritis/capsule stages → ring-enhancement
Sulci compressed but don’t enhance unless meningitis also present
DWI shows restriction early, helps distinguish abscess from neoplasm
Meningitis
Diffuse > focal, symmetric > asymmetric
Rarely affects solitary sulci; multiple adjacent sulci typically involved
FLAIR, T1 C+ scans best for detecting subtle disease
Focal Cortical Dysplasia
History of longstanding seizures
Perisylvian most common location
Follows gray matter on all sequences (occasionally slightly hyperintense on FLAIR)
Does not enhance
MRS usually normalStay updated, free articles. Join our Telegram channel
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