This is based on the Spanish description I posted in my Reference comment ("inundar los ventrículos"). I don't find that many online references to it, so my confidence level is only a 3.

I've found this sentence online, although I can't tell if it's from a source translated from another language ... it's from an English-language journal:

" A case of rupture of an aneurysm of the right middle cerebral artery with ventricular inundation of the contrast medium during angiography is reported. "

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Note added at 57 mins (2014-05-05 22:26:34 GMT)
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Here's a sentence from the American Journal of Neuroradiology (online) ... but the authors are Italian:

"In the 24 hours that followed, 2 patients died: one from a devastating intracerebral bleeding with ventricular inundation and the other as a consequence of the intraprocedural MCA rupture"

I find more hits for "ventricular invasion" but also not as many as I would like.

I am unable to find "ventricular inundation" on bona fide UK medical sites, which is what I tend to base my research on

inondazione ematica > blood flooding - ProZ.com
www.proz.com › KudoZ home › Italian to English › Medical (general)‎
23 Oct 2009 - Downward brain herniation can occur when rapid flooding of blood into the ventricles causes a pressure gradient between the anterior and ...

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Note added at 12 hrs (2014-05-06 09:50:34 GMT)
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or

blood flooding the ventricles

Intensive Care in Neurology and Neurosurgery: ...
books.google.co.uk/books?isbn=8897419399
Daniel A. Godoy - 2013 - ‎Medical
Pathophysiological Basis for the Management of Acute Cerebral Injury Daniel A. ... The maximum score is assigned for blood flooding the lateral ventricles, ...

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Note added at 12 hrs (2014-05-06 09:58:57 GMT)
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or
blood ruptures into the ventricles

Chapter 27: Cerebrovascular disorders
https://www.dartmouth.edu/~dons/part_3/chapter_27.html‎
During systemic hypoxia, the brain is able to extract oxygen from the blood in increasing ..... This results in a calcium flood into the neuron, which is toxic to the .... Parenchymal hemorrhages often rupture into the ventricular system or into the ...

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Note added at 12 hrs (2014-05-06 09:59:50 GMT)
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you don't give any full Spanish context so I would work these suggestions into your translation.

We don't tend to say "inundation" in this context.