Clinical Applications of Cine MR

Evaluation of intracranial CSF flow was accomplished by the use of cine MR technique. In the cine MR, there were two methods of evaluation in CSF flow pattern. Qualitative and quantitative methods were called magnitude reconstruction and phase contrast mapping method, respectively. The image of magnitude reconstruction method can demonstrate areas of decreased CSF flow and help explain the cause of hydrocephalus. The image of phase contrast mapping method is more sensitive to fluid motion and may increase utility in the future for analysis of fluid flow. Cine MR is capable of showing both normal and abnormal intracranial CSF flow. Such a study can be easily added as an extra pulse sequence at the end of a routinely acquired MR examination. We evaluated 2 cases of the normal pattern of pulsatile flow within subarachnoid space and 3 cases of abnormal patterns of CSF flow(communicating hydrocephalus: 2 cases, arachnoid cyst in posterior fossa: 1 case). These observations were compared with pre- and post-operative CSF flow state. In conditions which result in alterations of flow, cine MR shows either obstruction or excessively turbulent flow within the CSF pathways. In our studies, the most distinctive pathological finding was bulk flow in the aqueduct of Sylvius. The authors suggest that this technique can be applied in a wide range of conditions where CSF pathway is altered including hydrocephalus, evaluation of the function of the shunt system and communication between arachnoid cyst and subarachnoid space . Moreover correct diagnosis is possible in patients with hydrocephalus, in whom the exact level of CSF obstruction can be determined. We believe that surgical decisions can be aided by careful analysis of these CSF cine MR studies. We discuss the normal and abnormal CSF flow findings and indications of cine MR CSF flow technique with literature review.

Assessment of Flow Dynamics of Cerebrospinal Fluid with Phase-contrast Cine MR Image

Phase contrast magnetic resonance imaging techniques can be used to evaluate the to-and-fro motion of cerebrospinal fluid(CSF) throughout CSF pathways between the ventricles and subarachnoid space of the brain and spine. This CSF motion is due to transmitted cardiac pulsation from systolic expansion of the cerebral hemispheres. To cover the entire cardiac cycle, peripheral cardiac triggering was used. Using this technique, we analyzed quantitative CSF motion over a cardiac cycle to distinguish normal CSF flow from that seen in hydrocephalus. We tested the reproducibility of the aqueductal CSF signal intensity on a phase contrast cine MR sequence in 28 patients with normal ventricle. Sixteen patients with obstructive hydrocephalus and 11 patients with normal pressure hydrocephalus(NPH) were investigated with the sequence before and after CSF diversion. The peak CSF flow velocity in aqueduct was significantly increased in patients with NPH and significantly decreased in patients with obstructive hydrocephalus(NPH group: 6.71cm/sec, control group: 2.94cm/sec, obstructive group; less than 1.0cm/sec). After LP shunting in NPH group, retrograde flow signal curves were anterogradely converted and the peak flow velocities were somewhat decreased(mean: 5.10cm/sec). The clinical diagnosis of NPH was well correlated with the results of cine MRI. After endoscopic third ventriculostomy in obstructive group, we could note increased CSF flow velocity both at prepontine cistern and precordal subarachnoid space with markedly increased flow at prepontine cistern. Phase contrast cine MRI is useful in evaluatng the CSF dynamics in patients with hyperdynamic aqueductal CSF (NPH) or aqueductal obstruction(obstructive hydrocephalus).