Marked cerebrospinal fluid void: indicator of successful shunt in patients with suspected normal-pressure hydrocephalus.

Abstract

The authors blindly reviewed the charts of 20 patients with normal-pressure hydrocephalus (a disease of unknown cause characterized radiologically as chronic communicating hydrocephalus and clinically by gait apraxia, dementia, and incontinence) who had undergone creation of a ventriculoperitoneal shunt. The initial clinical response to surgery was graded excellent, good, fair, or poor; 5-year follow-up was available in 55% of cases. The magnetic resonance (MR) images obtained in these patients were also blindly reviewed for the magnitude of cerebrospinal fluid (CSF) flow void (graded on the basis of extent rather than degree of signal loss) in the cerebral aqueduct. A significant (P less than .003) correlation existed between good or excellent response to surgery and an increased CSF flow void. The presence of associated deep white matter infarction on MR images did not correlate with a poor response to surgery. On the basis of these findings, it is suggested that patients who fulfill the clinical criteria of NPH and have an increased CSF flow void undergo creation of a shunt.

Idiopathic normal pressure hydrocephalus may be a “Two Hit” disease: Benign external hydrocephalus in infancy followed by deep white matter ischemia in late adulthood

“…The diagnosis of NPH was not confirmed by response to shunting. Although hyperdynamic CSF flow has been shown to correlate with response to shunting in symptomatic NPH patients (14,15), the surrogate measure is less convincing than shunt response per se (which was unfortunately not available). The height and weight of the patients were also not available to adjust for head size; the only mechanism to account for different body size was to compare men and women separately.…”

“…In eight suspected NPH patients in whom CSF velocity imaging was technically flawed due to cardiac arrhythmia or velocity aliasing, hyperdynamic CSF flow was diagnosed on the basis of a marked aqueductal CSF flow void on the proton density-weighted conventional spin-echo image (15). As noted previously (14), the CSF flow void is much less sensitive than when originally described (15), due to the ubiquitous use of flow compensation for the last two decades and fast spin echo for the last 10 years. Regardless, when the flow void is seen, it is very specific for hyperdynamic CSF flow.…”

Lumbar Puncture Test in Normal Pressure Hydrocephalus: Does the Volume of CSF Removed Affect the Response to Tap?

“…4,5 Tarnaris et al 6 performed a literature review of 69 studies published between 1980 and 2006 to examine the role of structural as well as functional imaging in providing biomarkers of favorable surgical outcome in NPH. The papers reviewed included studies of structural CT and MR imaging features; 4,6-9 phase-contrast MR imaging studies of aqueductal CSF velocity and stroke volumes; [10][11][12] and functional studies including xenon-enhanced CT, 13 FDG-PET, 14,15 singlephoton emission CT, 16 and MR imaging spectroscopy. 17 Studies…”

Intracranial Pressure versus Phase-Contrast MR Imaging for Normal Pressure Hydrocephalus

“…We found the association of hyperdynamic CSF flow and shunt responsiveness significant (P Ͻ .003). 4 With the subsequent ubiquitous use of flow compensation and fast spin-echo (with the rephasing effects of the multiple 180°r adiofrequency pulses), the CSF flow void sign became less sensitive (though it still remains highly specific). This result led us in the early 1990s to use PCMR to determine the volume of CSF flowing up or down over the cardiac cycle (ie, the ASV).…”