Thank-you for responding. Yes, even though OA flow should be high
resistant, this was a low resistant signal with well sustained mean
velocities of 40cm/s. There appeared to be a barely audible CRA signal of
7cm/s however, I wasn't positive because of not detecting the CRV and
having allot of other collaterals in the area.
She is scheduled here tomorrow for a repeat scan before she sees the doctor.
We are going to use your suggestions of having her look right and left to
study her gaze and compare the other eye. ( she is a "cash patient" and he
specifically only wanted a cursory look of the right eye, would make sense
to look at both).
She is also a poor historian and thinks she has seen an ophthalmologist in
the past but cannot recall his name.
I'll keep up updated and thanks again for the suggestions.
From: Paula Heggerick [mailto:[log in to unmask]]
Sent: Monday, September 13, 1999 7:01 PM
To: [log in to unmask]
Subject: Re: Orbital mass
There are a few pieces of information missing in what you have described.
described the OA as monophasic and reversed. Was it a high resistant signal,
because the flow normally in the OA is low resistant, forward flow (like an
ICA). It can be reversed secondary to collaterals, but continue to be of a
good velocity. What were the velocities. Normal velocities in the OA are
approximately 35 cm/sec. Did you obtain flow in the central retinal artery
and if so, what were those velocities (normal is 10-12 cm/sec). If the
velocities were down in both the OA and CRA, you probably have a case of
ocular Ischemic syndrome (OIS) vs clear-cup amaurosis.
Your other question of the optic nerve sheath being displaced. Did you ask
the patient to look to the right or left? Sometimes they just are not able
keep their gaze up (with the eye closed of course). If they did have an
orbital lesion that was displacing the optic nerve-if you look at the
with the lights on, their gaze should deviate nasal and they would be unable
to look straight ahead when asked to. There are many types of orbital
some more obvious than others. I would look at the other orbit for
comparison-is the texture of the orbital tissue similar?
The last thing you mentioned was the appearance of the optic nerve sheath.
There a lot of conditions that can affect the appearance of the optic nerve
sheath-pseudotumor cerebri, optic neuritis, optic nerve glioma, a
There can be a lot going on behind the globe-hope this helps a little. You
may want to run this by a good neurophthalmologist. I will be anxious to
what you find.