|ECR 2019 / C-2747|
|Role of 3D space sequence and susceptibity weighted imaging in the evaluation of hydrocephalus and proposal of refined definition and classification of hydrocephalus|
Methods and materials
Study Design and Duration:
This prospective study was conducted in our institute from January 2014 to December 2017.
Approval was obtained from the ethical committee.
Patients with hydrocephalus who were referred for MRI brain were enrolled for our study.
Informed consent was obtained from all patients or caregivers.
We included 109 patients with moderate to severe hydrocephalus based on Evans index.
We excluded patients >50 years (due to age related dilatation of ventricles), normal pressure hydrocephalus, those patients with brain atrophy or ex‑vacou dilatation, and those who were on treatment or undergone shunt procedures or other surgeries.
MRI brain was done using Siemens Magnetom Aera 48 Channel 1.5 Tesla Machine (Germany) using standardized institutional protocol, including T1W sagittal, T2W axial, FLAIR coronal, diffusion weighted image with ADC
mapping, gradient, MRA/MRV, and post contrast study (if needed). The additional sequences we included were as follows: 3D SPACE sequence and SWI. 3D SPACE sequence was obtained in a sagittal plane covering all the ventricles and cisterns.
The conventional images were reviewed independently by two senior neuroradiologists with 10‑year experience.
Another two neuroradiologists with same experience analyzed the special sequences.
In the first step, conventional sequences were analyzed carefully for any obstruction and were divided into communicating and noncommunicating hydrocephalus.
Our diagnostic criteria for obstructive hydrocephalus were based on direct or indirect signs.
Direct sign of obstruction was direct visualization of membrane, mass, hemorrhage, or any other cause leading to obstruction.
Indirect signs were proximal upstream dilatation of ventricles, bulging of the CSF fluid just proximal to the level of obstruction, and signal intensity change in proximal and distal sites of obstruction. Accordingly with conventional sequences, we had 63 patients of communicating and 46 patients of noncommunicating hydrocephalus.
Next step was analysis of 3D SPACE sequence in which careful scrutinization of every image was done. All CSF pathways, especially all possible areas of obstruction were examined with caution using 3D multiplanar reconstruction and maximum and minimum intensity projection.
The membranes causing obstruction were followed to their full extent and again classified as obstructing and nonobstructing membranes.
Using this sequence, 88 patients were diagnosed to have noncommunicating hydrocephalus. Of these 88 patients, 80 patients showed intraventricular obstruction, whereas 8 patients showed extraventricular obstruction. Remaining 21 patients showed communicating hydrocephalus.
Third step was the analysis of SWI to locate the areas of hemorrhage by examining phase, magnitude, combined, and MIP images. In SWI, 3 patients showed intraventricular hemorrhage (cerebral aqueduct and foramen of Magendie) causing obstructive hydrocephalus and 24 patients showed hemorrhage at various sites (both intraventricular and