We recently had a similar case, the patient was a 46 year old male with R
sided weakness and a normal head CT.  The vascular lab had a good quality
study with RICA velocities of 418/196 and LICA velocities of149/55.  The
RICA stenosis should have been a hemodynamically significant lesion to the
brain but no downstream effects (change in waveform morphology or
collateral flow) was seen on TCD.  An angio was done and read at 60%
stenosis.  A repeat carotid at the vascular lab showed essentially no
change in the RICA carotid stenosis.  The patient is returning to our lab
for both studies next week.  I presented the case at our QC meeting and we
had more questions than answers.  However, we do a lot of monitoring of
the MCA's for a variety of reasons.  When you observe a vessel over time
you can demonstrate in many people rising and falling flow which has been
shown in many instances to correlate with a phenomenon called "B" wave
seen in brain injured patients with changing intracranial pressures.  We
have observed a lot of variation in MCA velocity in a number of different
settings including sleep.  These changes are cyclical and may occur over
seconds or minutes and may double velocities.  As most sonographers are
not aware of these and not monitoring one signal for possible alterations
in flow, this could be one possible explanation.
Colleen Douville
Cerebrovascular Lab/Department of Neurological Surgery
University of Washington
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On Fri, 26 Jan 2001, kathryn sorrell wrote:

> bill.....
> have seen the same thing in our lab.... similar circumstances (high grade lesion
> one day w/symptoms - weeks later, poof.... down to mild stenosis by doppler
> criteria).  Although we couldn't prove it ( because pt. did not progress to
> CEA)... we felt strongly that what we saw was a plaque that hemorrhaged and
> acutely filled the lumen of the artery with its bulging surface.  At a later
> point the plaque evolved/remodeled/regressed ... whatever.
> In just the reverse, we performed a carotid on a hospitalized pt. ( preop CABG)
> who had a moderate stenosis (50-69%) by out doppler criteria. He went on to
> successful CABG, only to develop a stroke  a few days post op.  He was sent by
> the the lab and guess what.....that same 50-69% lesion was now > 80% (ED vel ?
> 140 etc. etc.).  The neurologist and surgeon called on us and asked how can this
> be.  At surgery, we had the answer... the plaque had hemorrhaged.
> regards, Kathryn
>
>
> Bill Schroedter wrote:
>
> > In a message dated 1/24/01 11:18:34 PM Eastern Standard Time,
> > [log in to unmask] writes:
> >
> > << Case one.: 70 plus  female in reasonable health with history of Right
> > sided CVA (left sided symptoms) in 11.2000. Carotid scan at a world class
> > institution by an outstanding sonographer demonstrated a Right ICA stenosis
> > extending over 1-2 cms starting within 1 cm from ICA origin. I had the
> > original hard copy which showed PSV: 490 cms/sec; EDV: 230 cms/sec.Recorded
> > images had accurate angle correction to line of ICA at 60 degrees. I scanned
> > the patient today at one of our centres in a Public hospital. Request form
> > asked for "Right carotid doppler as requested by vascular surgeon". There was
> > plaque in the region of interest but colour flow appearance was nowhere as
> > severe as original exam. I could accept this as a function of the better
> > resolution of my machine. However try as I might I could not get velocities
> > in excess of PSV: 150 and EDV: 80 CMS/sec.
> >  Almost universally, when I review  scans performed by other people, I can
> > reproduce their mistake when there is significant variance between their
> > results and mine. >>
> >
> > Doug,  We once had a case a good many years ago of a lady who presented with
> > a small CVA who had a significant stenosis, not the 80%+ but probably the
> > upper end of our 60-79% category, lets say 70% or so. As she had already had
> > a CVA she was sent home to wait for a while prior to being evaluated for CEA.
> > About 6 weeks later, this lesion had regressed to less than 40%. Same
> > technologist (me) same instrument, a lot of extra pictures. It is well known
> > that plaque can remold or evolve. It would seem that an acute event
> > demonstrates an unstable plaque, possibly with a denuded surface, hence the
> > embolic event, and then as healing occurs, the plaque heals and could
> > conceiveably end up causing less stenosis. I know there are others with more
> > knowledge about this.....Dr. Beach??
> >
> > Bill Schroedter
> > Venice,Fl
>