Diagnosis
Posterior vitreous detachment with subvitreal collection, and minimal
vitreous hemorrhage
Discussion
Vitreous hemorrhage is a common finding in patients with trauma. US is
useful in detecting the density and location of hemorrhage. In fresh,
mild hemorrhage, dots and short lines are displayed on B-scan and a chain
of low amplitude spikes is found on A-scan. The more dense the hemorrhage,
more opacities are seen on B-scan and higher is their reflectivity on
A-scan. If the hemorrhage spreads diffusely, it creates scattered low
amplitude echoes. Organization of blood creates interfaces that may have
a pseudomembranous appearance on B-scan and variable reflectivity on A-scan.
Variable degrees of posterior vitreous detachment (PVD) usually accompany
vitreous hemorrhage. On B-scan, detached vitreous is usually smooth and
may be thick posteriorly when blood is layered along its surfaces. Reflectivity
in cases of PVD varies from extremely low as in the normal eye to extremely
high as in the case of dense hemorrhage. Kinetic US typically shows an
undulating after-movement on B-scan, which normally allows the PVD to
be distinguished from less mobile retinal and choroidal detachments. On
A-scan, PVD typically exhibits marked horizontal and vertical spike after
movement. However, there are situations in which the acoustic behavior
of PVD is similar to retinal detachment, so the distinction of PVD from
retinal detachment may be quite challenging
Dr.
Rahul Sachdev, BR Diagnostics, Delhi
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