To call it or not to call it? That is the question!
Do you feel a bit wacky & wobbly when it comes to calling normal pressure hydrocephalus on imaging?
You don’t want to overcall it, but you don’t want to miss it either!
Here are the signs of NPH
🔹 Evans Index > 0.3
--Enlarged frontal horns relative to skull width → ventriculomegaly.
Remember it: “One out of three is too big for me!”
🔹 Periventricular White Matter Change
--T2/FLAIR hyperintensity from transependymal CSF flow.
Remember it: “Leaking pressure leaves a glow.”
🔹 Narrowing of the Posterior Cingulate Sulcus
--Tight high-convexity sulci from crowding at the vertex.
Remember it: “The top gets squeezed shut.”
🔹 Effaced Vertex CSF Wide Sylvian Fissures
--Tight sulci up top but enlarged fissures laterally (DESH pattern).
Remember it: “Dry on top, wet on the sides.”
🔹 Upward Bowing of the Corpus Callosum
--Ventricular expansion pushes the corpus callosum upward.
Remember it: “If the corpus callosum is arched, the patient can’t march (wobbly)”
🔹 Temporal Horns > 6 mm
--Early temporal horn dilation from hydrocephalus.
Remember it: “Big horns before big vents.”
🔹 Focally Dilated Sulci at the Vertex
--Patchy enlarged sulci despite surrounding crowding.
Remember it: “Holes in a leaky roof = too much water on the brain!”
🔹 APV Index > 0.5
--Increased ventricular-to-parenchymal proportion suggesting hydrocephalus.
Remember it: “Glass half full is too much!”
🔹 Prominent Aqueductal Flow Void
--Increased CSF flow through the aqueduct on MRI.
Remember it: “If the aqueductal flow is super black, the ventricles are out of whack.”
Classic NPH imaging theme: enlarged ventricles tight high convexities disproportionate CSF redistribution.
Hopefully now you won't wobble on the diagnosis of NPH!!