Interactive Transcript
0:00
This is an MRI of the brain in a one-week-old
0:04
child that had an abnormal fetal
0:06
MRI and fetal ultrasound,
0:09
we can see massive enlargement of both lateral
0:12
ventricles and the third ventricle.
0:15
But if we go inferiorly,
0:18
the fourth ventricle is nondilated.
0:20
And further confirming our suspicion on the fetal MRI,
0:25
we do not see a cerebellar vermis.
0:28
We see midline continuity of
0:30
the cerebellar hemispheres.
0:32
Sagittal image again shows massive enlargement
0:36
of the lateral ventricles,
0:38
enlargement of the third ventricle,
0:41
distension of the superior aspect of the
0:44
aqueduct of sylvius, but tapering.
0:46
The aqueduct of sylvius tapers,
0:49
and we do not see any patency of
0:54
that caudal to this point.
0:56
This is, therefore, a congenital aqueductal stenosis
1:01
with triventricular hydrocephalus.
1:04
By triventricular,
1:05
I mean the two lateral ventricles in the third ventricle,
1:08
and the fourth ventricle is not dilated.
1:10
Now, while the fourth ventricle is not dilated,
1:13
it's not normal.
1:13
It has an abnormal configuration.
1:16
Now,
1:16
that abnormal configuration is partially because
1:18
these massively enlarged ventricles are distorting
1:21
everything in the posterior cranial fossa.
1:24
But if we look on this axial image,
1:28
we can see the cerebellum in the fourth ventricle
1:31
probably did not develop normally,
1:33
but it's very difficult to tell for several reasons.
1:37
To fully characterize it,
1:38
it's helpful if the child is older,
1:41
the brain is larger,
1:43
and right now, the massively enlarged lateral
1:47
ventricles are impairing our ability to understand
1:51
the normal configuration of the
1:53
postcranial fossa.
1:54
Well, approximately a year later,
1:58
an MRI was performed.
1:59
We can see a ventriculostomy catheter in place.
2:03
The ventricles have come down markedly in size,
2:06
and now we can see there is no cerebellar vermis.
2:12
The posterior margin of the cerebellar hemispheres
2:15
forms this contiguous arc right here,
2:18
continuity between the two cerebellar hemispheres.
2:22
So, this is a case of rhombencephalosynapsis with
2:28
additionally congenital aqueductal stenosis,
2:32
possibly related to incomplete transverse
2:35
migration of the intercolliculi,
2:37
also referred to sometimes as
2:39
mesencephalosynapsis.
© 2024 MRI Online. All Rights Reserved.