Changes in Aqueductal CSF Stroke Volume and Progression of Symptoms in Patients With Unshunted Idiopathic Normal Pressure Hydrocephalus

Abstract

BACKGROUND AND PURPOSE:Idiopathic normal pressure hydrocephalus (iNPH) represents a diagnostic challenge, given its variable presentation and progression. Stroke volume (SV), defined as the mean volume of CSF passing through the aqueduct during both systole and diastole, greater than or equal to 42 L, serves as a selection criterion for patients with good probabilities of improvement after ventriculoperitoneal shunt surgery (VPS). In this study, we evaluated the changes in SV during the progression of clinical symptoms in patients with suspected NPH.

The formation of cerebrospinal fluid: Nearly a hundred years of interpretations and misinterpretations

“…Regrettably, in many other studies where CSF movement in the aqueduct of Sylvius has been examined in physiological conditions by different MR imaging techniques, the obtained results did not allow presentation of the rate of CSF formation (V f ) neither from reported flow values nor from the CSF velocity (Baledent et al, 2006;Barkhof et al, 1994;Florez et al, 2006;Kim et al, 1999;Lee et al, 2004;Luetmer et al, 2002;Mase et al, 1998;Schroeder et al, 2000;Scollato et al, 2008;Stahlberg et al, 1989). The reason for this lies in the fact that attempts have been made to diagnose pathologic changes by means of other, more easily measurable hydrodynamic parameters in the aqueduct of Sylvius (see above).…”

“…This assumption has rarely been reported in literature (Di Chiro, 1964;Weed, 1914). It is believed that CSF flow is augmented by the ciliary action of the ventricular ependyma, vascular, choroidal and respiratory pulsations, cardiac systole and diastole and the hydrostatic pressure gradient that exists between the CSF and the venous system (Bering, 1962;Bering and Satto, 1963;Bhadelia et al, 1995;Di Chiro, 1964;Du Boulay, 1966;Du Boulay et al, 1972;Florez et al, 2006;Lee et al, 2004;Mascalchi et al, 1988;Milhorat, 1975;O'Connel, 1970;Ohara et al, 1988;Scollato et al, 2008;Thomsen et al, 1990).…”

Guidelines for Management of Idiopathic Normal Pressure Hydrocephalus: Second Edition

“…It is controversial whether the above imaging diagnosis predicts the shunt response, 23,24,32,41,72) but measurements of the preoperative peak flow velocity of CSF 103,122) and stroke volume, reflecting the CSF volume following the cerebral aqueduct, 6,120,121) have been reported to be clinically useful predictors of the shunt response, and these may be considered for preoperative examinations; however, the measurement methods have not been standardized and their diagnostic value has not been established. Reduced venous circulation in the sagittal and straight sinuses and intracranial compliance on heart rate-gated phase-contrast MRI have been reported, 11,12) but their diagnostic values have not been established.…”

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

“…3 All 13 patients with an ASV of Ͼ42 uL on that particular MR imaging system responded to shunting, while only half of the 6 patients with an ASV of Ͻ42 uL responded (ie, the ASV as we measured it had a 100% positive predictive value). While we initially thought that all the patients with ASVs of Ͻ42 uL had atrophy, Scollato et al 5 pointed out that some of these patients may, in fact, have been very early in their disease because their ASV 6 months later was increased. Ringstad et al 1 pointed out that some investigators have been unsuccessful in using the ASV to discriminate those patients who will respond from those who will not respond to shunting for NPH.…”