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This is a T2-weighted MRI scan of a patient

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who was blind in the left eye.

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As we scroll through the images,

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we see that there is a discrepancy in the size of the

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globes between the right eye and the left eye.

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And we also see that the patient has a congenital anomaly

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of the brain. But let's focus on the left eye for a moment.

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As you can see, the left eye is smaller than the right eye.

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We also note a discrepancy in the signal intensity of the

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vitreous humor between the right eye and the left eye.

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For right now, we're going to focus on the left eye.

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So this is a patient who has microphthalmos,

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a small left eye.

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Not only that,

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but we also see that there is faintly seen a linear

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structure which appears to be oriented in the anterior

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posterior dimension in this eye.

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This might be better seen

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as we scroll more superiorly.

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More superiorly,

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we see this structure which is oriented

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and seems to be bifurcating the globe.

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We also note that the patient does not

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seem to have a lens of the eye.

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In addition, the left optic nerve is small in size.

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This is a patient who has an entity known as

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Persistent Hyperplastic Primary Vitreous,

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also known as PHPV.

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This is due to persistence of the embryonic hyaloid

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vascular system, in which a blood vessel is seen

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coursing from anterior to posterior

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as the hyaloid artery within what is called Cloquet's canal.

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So this linear structure is what is known as Cloquet's canal

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and it is associated with PHPV,

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Persistent Hyperplastic Primary Vitreous,

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a cause of ocular blindness and microphthalmos

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and is a congenital anomaly.

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These patients also may have a higher incidence of retinal

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hemorrhages. And so as one scrolls the study,

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one might also note that there is a small amount of

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abnormal signal intensity along the

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posterior aspect of this globe.

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This is seen along the temporal aspect where

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we see intermediate signal intensity tissue,

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which should not be there,

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which represents a retinal hemorrhage,

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in association with PHPV.

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This is a cause of leukocoria,

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which is loss of the red pupillary reflex in a child.

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The most common cause of loss of the red reflex or

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leukocoria in a child is a disease called retinoblastoma,

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a tumor of the globe.

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As opposed to retinoblastoma,

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in which 90% of cases calcify,

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PHPV does not calcify and is associated with a small globe.

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Retinoblastoma is associated with a normal-sized globe.

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With respect to the other findings in this patient,

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one has a very large arachnoid cyst

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in the right hemisphere,

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and one also notes that there is absence of separation

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between the two hemispheres in this patient

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who also has holoprosencephaly.

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The right globe shows abnormal signal intensity within

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it, and this was secondary to a vitreous hemorrhage.