CSF flows dynamics versus morphological and pressure-related parameters considered in NPH patients
Résumé
Introduction: Cerebrospinal fluid (CSF) stroke volume measured through the aqueduct of Sylvius (SVaq) by phase-contrast MRI (PC-MRI) is one of the most discussed image-based biomarkers proposed as a possible indicator of positive surgical outcome in normal pressure hydrocephalus (NPH) patients. Alternatively, CSF stroke volume through the spinal compartment (SVc2c3) can also be measured by PC-MRI. This study combines clinical, morphological, and pressure-related parameters considered in NPH patients’ management to evaluate potential relationship between these parameters and the Svaq and the SVc2c3.
Methods: 28 patients (74 ± 9 years) with suspected NPH underwent clinical examination, PC-MRI and infusion test. We measured by PC-MRI, CSF flows dynamics in the cerebral aqueduct and in the spinal canal at C2-C3 level. Then SVaq and SVc2c3 were calculated. Moreover, physicians also estimated other different features: Evans’ index, callosal angle, DESH score, iNPH score, Resistance to CSF outflow (Rout).
Results: Svaq showed a poor correlation with the different features evaluated, however, SVc2c3 presented statistically significant correlation with Rout (R2 = 0.33, p = 0.0028).
Conclusions: Although SVaq has been proposed to predict surgical outcome of patients with NPH, it presented a poor correlation with complementary markers commonly evaluated for diagnosis. More interestingly, these preliminary results showed that SVc2c3 has a significant correlation with Rout, a complementary parameter used to predict shunt responsiveness in NPH patients. Indeed, SVc2c3 represent the CSF volume flush quickly ejected from the intracranial compartment as a compensatory response to vascular brain expansion, which could explain the relationship with the resistance to CSF outflow.