T1 Hyperintense CSF
Bronwyn E. Hamilton, MD
DIFFERENTIAL DIAGNOSIS
Common
MR Artifacts, Flow-Related
MR Artifacts, Magnetic Susceptibility
Subarachnoid Hemorrhage
Intraventricular Hemorrhage
Meningitis
Less Common
Ventriculitis
Rare but Important
Dermoid Cyst (Ruptured)
Carcinomatous Meningitis
Contrast Complications, NOS
Retained Pantopaque
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
MR artifact common at high field strengths
CSF hemorrhage & infection often causes “dirty CSF”, hyperintense to CSF & isointense to brain parenchyma
CSF FLAIR hyperintensity more common than true T1 CSF hyperintensity
Helpful Clues for Common Diagnoses
MR Artifacts, Flow-Related
Pulsation artifact in phase encoding direction
Confirm artifact when seen outside skull
MR Artifacts, Magnetic Susceptibility
“Black holes” with T1 bright rim
Changing phase encode direction confirms
Subarachnoid Hemorrhage
May be traumatic, aneurysmal, or nonaneurysmal perimesencephalic
Location helps determine etiology
Typically isointense to brain, “dirty CSF”
Intraventricular Hemorrhage
Typically hyperintense to CSF & isointense to brain with a fluid level
May be T1 hyperintense, related to age
Meningitis
Typically isointense to brain, “dirty CSF”
Meningeal enhancement classic
Helpful Clues for Less Common Diagnoses
Ventriculitis
Debris in ventricles from sediment, cells
Typically hyperintense to CSF & isointense to brain with a fluid level
Helpful Clues for Rare Diagnoses
Dermoid Cyst (Ruptured)
Fat droplets within CSF spaces
Suppress with fat-saturation
Carcinomatous Meningitis
Rare, related to blood, cells, melanoma
Contrast Complications, NOS
Chronic renal failure causes delayed excretion & hyperintensity from recirculation
Gadolinium leak from lack of intact blood-brain barrier: Infection, PRES
Retained Pantopaque
Often focal T1 hyperintensity in CSF
Older adults (not used since 1980s)
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