IntroductionNumerous reports provide evidence to support the use of sensitive MR imagingtechniques for the assessment of cerebrospinal fluid (CSF) hydrodynamics in variouspathological conditions. Cine phase contrast MR imaging has been increasingly usedduring the last decade for evaluating cranial and spinal CSF flow. Assessments ofCSF flow indicate the potentials of using phase contrast MR imaging for quantitativeand qualitative CSF flow analysis. It is a useful adjunct to routine MR in theevaluation of pathological CSF flow dynamics in normal pressure hydrocephalus(NPH), aqueductal stenosis and Arnold Chiari malformation.Aim of workThe aim of our study is to assess the value of cine-phase contrast MRI CSF flowmetryin cases of aqueductal stenosis, Arnold-Chiari malformation & normal pressurehydrocephalus and to differentiate the latter from atrophy.Patients- methodsA CSF flow study was performed with the use of an optimized two dimensional cinephase-contrast MR technique. 7 normal volunteers and 13 patients with abnormal CSFhydrodynamics were enrolled. The patient group includes 5 normal pressurehydrocephalus cases, 3 cases of atrophy, 3 cases of aqueductal stenosis and 2 caseswith Arnold-Chiari I malformation. The diagnoses of NPH were made according tothe clinical symptoms (dementia, urine incontinence, drowsiness, gait disturbances, headache, and seizures) and MR imaging criteria (the presence of ventriculomegaly(+/-out of proportion to sulcal widening) and prominent aqueductal flow void signal).Criteria used for aqueductal stenosis were 1) clinical manifestations of increasedintracranial pressure and 2) imaging findings of marked narrowing of the aqueduct onsagittal MRI brain images as well as marked dilatation of the lateral and 3rd ventricles.As for chiari I, the patients had neurologic symptoms and signs referable to thissyndrome such as cough- or strain-related headache, ataxic gait, or sensory deficit.They had MR images available, including T1- and T2-weighted sagittal view imagesof the cervical spine that revealed tonsillar descent into the foramen magnum,consistent with the diagnosis of Chiari I malformation. One of them hadsyringomyelia. Two protocols of examination were used: the first one involvedquantitative and qualitative analysis of CSF flow properties at the level of theaqueduct of Sylvius and was applied to NPH patients, cases of atrophy and aqueductalstenosis and 5 of the healthy volunteers. The other protocol was applied to cases ofArnold Chiari I malformation and 2 healthy volunteers and involved CSF flow studyin the axial plane at the foramen magnum.Results and conclusionCorrelative statistical analysis was done and revealed that the systolic peak and meanvelocity as well as the systolic stroke volume values in NPH patients were statisticallysignificantly higher than those of the normal controls; these results indicate thatpatients with normal pressure hydrocephalus have hyperdynamic aqueductal CSFflow. In cases of atrophy, we found statistically significant markedly lower systolicpeak velocity, end-diastolic peak velocity and stroke volume values in comparison tohealthy volunteers indicating a hypodynamic CSF circulation. In cases of aqueductal stenosis, lack of significant aqueductal CSF flow wasnoticeable. Both the peak systolic velocity and peak diastolic velocities were lower inthe patients than in the control volunteers.In Arnold-Chiari I malformation, our study revealed marked inhomogeneity of flow.The peak systolic velocity and peak diastolic velocity were statistically higher in thepatients than in the control volunteers.Our results confirm the value of cine phase MRI as a validated tool for characterizingCSF hydrodynamics in various pathological conditions. They also confirm that an MRimaging evaluation of CSF potentially can be very helpful in distinguishing cases ofNPH from cases of atrophy before any CSF diversion procedure is contemplated.