The Efficiency of PC-MRI in Diagnosis of Normal Pressure Hydrocephalus and Prediction of Shunt Response

Rationale and Objectives

In this prospective study, we aimed to reveal the efficiency of phase-contrast magnetic resonance imaging (PC-MRI) in the diagnosis of idiopathic normal pressure hydrocephalus (INPH) and prediction of shunt response.

Materials and Methods

The study group consisted of 43 patients with INPH diagnosis and 15 asymptomatic age-matched controls. PC-MRI studies were applied on cerebral aqueduct and superior sagittal sinus (SSS) in all the cases.

Results

The maximum and mean cerebrospinal fluid (CSF) flow velocities were significantly higher in the INPH patients compared with the controls (P < .05). CSF stroke volume (43.2 ± 63.8 μL) and output/min (3921 ± 5668 μL) were remarkably higher in the NPH group compared with the control group (3.9 ± 3.9 μL, 439 ± 487 μL, respectively) (P < .05). Maximum and mean venous velocity values of the INPH patients (maximum, 19.2 ± 4.3 cm/s; mean, 16 ± 3.7 cm/s), were lower than those of the control group (maximum, 21.8 ± 4.6 cm/s; mean, 18.9 ± 3.9 cm/s) (P < .05). Stroke volume and venous output/min values of INPH patients in SSS, were significantly lower than those of the control group (P < .001, P = .007, respectively). The response of INPH patients against shunt treatment showed no statistical correlation with any of the PC-MRI parameters (P > .05).

Conclusion

The measurement of CSF venous flow velocities with PC-MRI is a noninvasive test that benefits INPH diagnosis, but remains inadequate in prediction of response against shunt treatment.

Key Words: Cerebral blood flow, magnetic resonance imaging, normal pressure hydrocephalus, PC-MRI, cerebrospinal fluid flow dynamics, subarachnoid space, shunt