The pathophysiology of idiopathic normal pressure XXXX : @entity2806 or altered venous hemodynamics?

@entity1 @entity64 @entity2758 @entity2806 @entity1276 @entity63
BACKGROUND AND PURPOSE: Many theories of normal pressure @entity1276 (NPH) stress the importance of @entity63 in the deep white matter. Alternate theories stress a reduction in superficial venous compliance and changes in pulse-wave propagation. An overlap in the cerebral blood flow volumes measured between NPH and controls suggests that @entity63 may not be a prerequisite for this condition. This study sought to compare blood flow and compliance measures in a cohort of @entity1 with NPH selected for having arterial inflows above the normal range to see if deep @entity2806 or superficial hemodynamic changes contribute to the pathophysiology of NPH. MATERIALS AND METHODS: Twenty @entity1 with NPH and arterial inflows above the normal range were selected. They underwent MR imaging with flow quantification measuring the total blood inflow, sagittal/straight sinus outflow, aqueduct @entity64 volume, and @entity2758 ( @entity2758 ). @entity1 were compared with 12 age-matched controls. RESULTS: The deep outflow volumes were normal. The superficial venous outflow was reduced as a percentage of the inflow by 9% (P = .04). The sagittal sinus compliance as measured by the @entity2758 was reduced by 50% (P = .0001), and the aqueduct @entity64 volume was elevated by 192% (P = .02). CONCLUSION: @entity63 in the deep venous territory is not a prerequisite for NPH. @entity1 with high-inflow NPH show alterations in superficial venous compliance and a reduction in the blood flow returning via the sagittal sinus. These changes together suggest that an elevation in superficial venous pressure may occur in NPH.
