Diffusion-weighted magnetic resonance imaging of cerebrospinal fluid in patients with and without communicating hydrocephalus.
BACKGROUND
Recent concepts about cerebrospinal fluid (CSF) circulation in communicating hydrocephalus (CoHy), which is also termed "restricted arterial pulsation hydrocephalus," suggest reduced arterial pulsations of subarachnoid vessels with a smaller amount of CSF shifted in subarachnoid spaces during the early systole. The postulated restriction of subarachnoid arterial pulsations in CoHy should induce a smaller motion artifact and reduced local stream effects in CSF in magnetic resonance (MR) diffusion-weighted imaging (DWI).


OBJECTIVE
To investigate the maximum diffusivity in CSF in patients with and without CoHy using DWI.


METHODS
12 patients without CSF circulation disturbances and six cases with proven CoHy were assessed. Diffusion was measured in six non-collinear directions without triggering the arterial pulse wave (scan time 6:45 min, voxel size 2x2x2 mm). Due to expected artifacts, the calculated maximum diffusivity was called apparent diffusivity. Regional high and low apparent diffusivity was assessed in CSF spaces on newly created 3D CSF motion maps.


RESULTS
Patients with regular CSF circulation exhibited high apparent diffusivity in CSF in basal subarachnoid spaces, whereas apparent diffusivity was low there in patients with CoHy.


CONCLUSIONS
DWI opens a feasible approach to study CSF motion in the neurocranium. Restricted arterial pulsations seem to be involved in CoHy.
Nasel
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Cerebrovascular Imaging Workgroup of the Division of Neuroradiology, Department of Radiology, Medical University Vienna, Währingergürtel 18-20, A-1090 Vienna, Austria. christian.nasel@meduniwien.ac.at
Gentzsch
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S
Heimberger
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D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D016022:Case-Control Studies; D002555:Cerebrospinal Fluid / Q000502:physiology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000473:pathology / Q000503:physiopathology*; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology*; D013346:Subarachnoid Space / Q000473:pathology / Q000503:physiopathology