Relationship Between Ventricular Morphology and Aqueductal Cerebrospinal Fluid Flow in Healthy and Communicating Hydrocephalus

Abstract

Aqueductal CSF flow is strongly correlated with ventricular morphology, especially with the total ventricular volume and the third ventricle width, but not with the tested hydrodynamic parameters. In addition, ASV is linearly correlated with aqueductal lumen area, suggesting that the aqueductal CSF flow characteristics can be explained by oscillating pressure differences on the order of less than 0.01 mmHg. These findings may explain why a standalone ASV is a poor diagnostic marker and an insensitive indicator of shunt outcome in idiopathic normal pressure hydrocephalus.

Aqueductal Stroke Volume: Comparisons with Intracranial Pressure Scores in Idiopathic Normal Pressure Hydrocephalus

“…A positive shunt response can be considered a marker of "true" iNPH, and the high response rate suggests that our study cohort was representative of iNPH and contained few patients with diseases that clinically might present similarly, with similar ASV values. 32 We reproduced previous findings of ASV being elevated in patients with iNPH compared with healthy controls 33 and in contrast to elderly patients in general, in whom ASV has been reported to be reduced. 34 However, ASV varied over a wide range in patients found both eligible and noneligible for surgical shunting on the basis of MWA, and ASV values overlapped between the groups.…”

“…14 ASV also correlated positively with ventricular volume before shunting; this correlation confirms previous observations 33 but is contradictory to a more recent study by Chaarani et al 36 In our study, the statistical significance of this positive correlation was dependent on 1 patient with extreme values, both ASV and ventricular volume.…”

“…36 In this study, a strong association between aqueductal area and ASV was found; however, this does not necessarily imply causality. As pointed out by Chiang et al, 33 it seems reasonable that the aqueduct can adapt to increased flow, similar to the ad- aptation of the blood vessel lumen area to maintain a wall shear stress within a normal range. 37 ASV and ventricular volume declined after shunting; this change is consistent with that in previous studies, 14,38 while aqueductal area did not change.…”

“…27,33 However, measurements of aqueductal flow can be influenced by flow aliasing, which is characterized by its apparent high velocity in the opposite direction to the average velocity in the defined area of interest. This was corrected for with the same algorithm applied to all patients, as described in the "Materials and Methods" section.…”

Cine cerebrospinal fluid imaging in multiple sclerosis

“…Cine phase contrast MRI has been previously used for CSF flow quantification in healthy controls (HC), patients with hydrocephalus, stroke patients, the elderly, etc (6)(7)(8)(9).…”