Learning objectives

1. To learn the relevant pathophysiology of Hydrocephalus.

 2. To learn the physics of cine mode (Phase contrast) MRI brain sequences and detail the acquisition protocols, including tips and tricks.  

3. To define an approach to interpretation of the Cine Mode (Phase-Contrast) images, as an adjunct to conventional sequences in pre- and post –operative evaluation of Hydrocephalus.

Background

Hydrocephalus is usually defined as ventriculomegaly with sulcal effacement and can be classified as communicating, non- communicating or Normal Pressure Hydrocephalus. Communicating Hydrocephalus is implied if the level of the obstruction is distal to the 4th ventricle while non communicating hydrocephalus is implied if the level of obstruction is cranial to the 4th ventricular outflow. Normal Pressure hydrocephalus is a special sub-class of hydrocephalus with disproportionate ventricular dilatation relative to sulcal prominence. 

Findings and procedure details

Physics & Technique

 CSF Flow is pulsatile & is synchronized to cardiac pulsations, with a phase difference between cardiac pulsations and CSF pulsations, resulting in caudad CSF flow during cardiac systole and cephalad CSF flow during cardiac diastole. Typical CSF flow velocities are in the range of 5 to 8 cm/s. In hyperdynamic circulations, velocities can go up to 25 cm/s.

Conclusion

Proper evaluation of hydrocephalus on MRI needs a basic understanding of physiology of CSF flow dynamics as well the physics behind the MRI protocols. Correct imaging plan including the protocol parameters and planes of imaging is as important as the knowledge of imaging presentations to avoid misinterpretation and misdiagnosis.

Link to complete publication here: https://scholar.google.com/citations?view_op=view_citation&hl=en&user=dqpMNRUAAAAJ&cstart=20&pagesize=80&citation_for_view=dqpMNRUAAAAJ:0EnyYjriUFMC