UNASSIGNED: OBJECT The objective of this study was to assess the net @entity64 ( @entity64 ) and CSF aqueductal flow rate derived from phase-contrast MRI (PC-MRI) in @entity1 with probable @entity5083 ( @entity5083 ) before and after ventriculoperitoneal shunt surgery, and to compare observations with intracranial pressure (ICP) scores. METHODS PC-MRI at the level of the sylvian aqueduct was undertaken in @entity1 undergoing assessment for probable @entity5083 . Aqueductal flow in the craniocaudal direction was defined as positive, or antegrade flow, and net @entity64 was calculated by subtracting retrograde from antegrade aqueductal flow. Aqueductal flow rate per minute was calculated by multiplying net @entity64 by heart rate. During the same hospital admission, clinical examination was performed using NPH score and overnight continuous ICP monitoring. Twelve @entity1 were followed prospectively 12 months after shunt placement with clinical assessment and a second PC-MRI. The study also included 2 healthy controls. RESULTS Among 21 @entity1 examined for @entity5083 , 17 (81%) received a shunt (shunt group), and 4 were treated conservatively (conservative group). Among the @entity1 with shunts, a clinical improvement was observed in 16 (94%) of the 17. Net @entity64 was negative in 16 (76%) of 21 @entity1 before shunt placement and in 5 (42%) of 12 @entity1 after shunt placement, and increased from a median of -5  l (range -175 to 27  l) to a median of 1  l (range -61 to 30  l; p = 0.04). Among the 12 @entity1 with PC-MRI after shunt placement, 11 were shunt responders, and in 9 of these 11 either a reduced magnitude of retrograde aqueductal flow, or a complete reversal from retrograde to antegrade flow, occurred. Net @entity64 was significantly lower in the shunt group than in the conservative group (p = 0.01). The aqueductal flow rate increased from -0.56 ml/min (range -12.78 to 0.58 ml/min) to 0.06 ml/min (range -4.51 to 1.93 ml/min; p = 0.04) after shunt placement. CONCLUSIONS In this cohort of @entity1 with @entity5083 , retrograde net aqueductal flow was observed in 16 (76%) of 21 @entity1 . It was reversed toward the antegrade direction after shunt placement either by magnitude or completely in 9 (75%) of 12 @entity1 examined using PC-MRI both before and after shunt placement (p = 0.04); 11 of the 12 were shunt responders. The study results question previously established concepts with respect to both CSF circulation pathways and CSF formation rate.

Phase-contrast magnetic resonance imaging reveals net retrograde aqueductal flow in XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity5083 :: ('MESH:D006850', 'Disease') :: ['idiopathic normal pressure hydrocephalus', 'iNPH'] @entity64 :: ('MESH:D020521', 'Disease') :: ['ASV', 'aqueductal stroke volume']
@entity5083 :: (MESH:D006850,Disease) :: ['idiopathic normal pressure hydrocephalus']
