Neurovascular Ultrasound Outpatient Clinic
Transcranial duplex ultrasound is a noninvasive method to assess the intracranial
vasculature in real time. Whereas the assessment of extracranial pathologies, such as
carotid
artery
occlusion or stenosis,
atherosclerosis
or
vessel wall dissection
using
duplex
ultrasound
is
well
established, the use
of duplex ultrasound
to image and assess
brain
vessels
sparse.
disconnect
extra-
is
The
between
and
transcranial vascular assessment does not seem to be very reasonable, from a
diagnostic point of view, in many applications, such as pre/post stroke care or
atherosclerosis
evaluation.
Commonly, other imaging techniques like cranial MR-, X-ray or CT-Angiography are
used to visualize the intracranial vasculature. This methods, however, are rather costly
compared to ultrasound and do not provide information about flow dynamics in real
time.
Alternatively, transcranial duplex ultrasound could be suitable for those patients
where a neurovascular assessment is indicated, but cranial MR-, X-ray or CTAngiography are not necessarily justified, due to cost limitations. Further, transcranial
duplex ultrasound might be used as a preferred monitoring tool, for example after
stroke or an intracranial vascular intervention, or it could be used as a stroke prescreening tool in patients who suffer from cardiovascular risk factors. A short list of
MediCare approved indications is given below:

Focal cerebral or ocular transient ischemic attacks

Evaluation of nonhemispheric or unexplained neurologic symptoms.

Re-evaluation of existing carotid stenosis.

Follow-up after a carotid endarterectomy.

Preoperative evaluation of patients scheduled for major cardiovascular surgical
procedures.

Drop attack or syncope.

Evaluation of suspected dissection.

Amaurosis fugax.

Subclavian steal syndrome.

Blunt neck trauma.

Evaluation of pulsatile neck mass.

Cervical bruits.
The UCSD Neurovascular Outpatient Clinic has recently opened and is located at the
UCSD Sulpizio Cardiovascular Center. The aim of this presentation is to introduce the
new service to the members of the San Diego Neurological Society.
Prehospital Stroke Diagnosis and Treatment
Stroke is the second common cause of death and the leading cause for early
invalidity worldwide. Whereas established as well as innovative treatment options are
sparse, the time between symptom onset and start of treatment is still by far the
most limiting factor. A neuronal death rate of almost 2.000.000 nerve cells every
minute, for ischemic stroke,
underscores
anything
better
else
the
than
urgent
need for treatment options
which could be applied at the
earliest timepoint possible.
To
date,
options,
restricted
all
treatment
however,
to
hospitalization,
the
are
patient’s
converting
stroke therapy into a race
against the clock. In this regard, the goal of stroke diagnosis at the earliest timepoint
possible, means at the site of the emergency or during transport, seems to be
reasonable. More so, if beyond stroke diagnosis a treatment option could be
provided already ‘in the field’. The use of wireless technology could have a
tremendous impact since it would not only allow immediate evaluation of the brain
vessels by a stroke expert in a remote fashion. Moreover, it would promote the
decision making process whether a patient might suffer from ischemic stroke (vessel
occlusion yes/no), whether a patient should be referred to a specialized facility or,
most important, whether early treatment could be initiated already at the site of the
emergency or during patient transport (keyword: sonothrombolysis). To accomplish
this goal the San Diego Prehospital Stroke Project will start in January 2012. The
project will be divided into three steps. During Step 1, the feasibility of prehospital
brain imaging using ultrasound and the wireless data transfer to a dedicated server
at the UCSD Stroke Center will be tested. Once feasibility has been shown it is the
aim for Step 2 to train paramedics in transcranial duplex ultrasound and to use
multiple, portable ultrasound devices equipped with wireless capability. During Step 2
the data will be sent remotely to the UCSD Sulpizio Cardiovascular Center where a
stroke and ultrasound specialist will evaluate the image data and correspond with the
paramedics in real time. It is the intention for Step 2 to enroll ‘Code Stroke’ patients
only. Step 3 of this project will focus on the ultimate goal of this project which is the
treatment of stroke victims before they even arrive at the hospital. Recent studies at
the UCSD Brain Ultrasound Research Lab confirm the hypothesis that noninvasive,
transcranial ultrasound, as it is used for diagnostic purposes to visualize brain vessels,
has the potential to break up blood clots efficaciously and safely. Once the
preliminary results can be confirmed a true treatment option for stroke, applicable
already ‘in the field’, would be available. The major clinical impact will be that
thousands of stroke victims in San Diego County could potentially be treated who are
now not eligible for any other treatment option (ie. tissue Plasminogen Activator, tPA).