Issues in Imaging for Stroke

Shawn Halpin MRCP FRCR LLM

University Hospital of Wales, Cardiff

National Intercollegiate WP for Stroke 2004

Hospital care

specialist teams

weekly MDT

SITS MOST

contd...

“initial assessment by experienced clinician”

“non specialist care costs lives, increases dependancy, less cost effective”

brain imaging within 24 hours

MRI if CT delayed for 10 days

Audit data:

How many patients imaged within 24 hours?

Wales criticised for worst UK performance

But 97% patients scanned within 24 hours of request

New report

Immediate imaging for certain stroke subgroups - thrombolysis, unconscious, warfarin

Immediate review by an expert in stroke

Immediate (1hr) scan?

Trivial to provide

Immediate clinical diagnosis

Very difficult

large/small vessel; TIA; migraine; SAH; dissection, watershed, global etc etc

3 patient with limb fractures referred as acute stroke patients

Plain scan in early stroke:

Usually normal

Rush to treat:

Undoubtedly some non-stroke patients will be treated with rTPA

Early CT signs:

Add specialist neuroradiological

advice

Non Trivial

Network?

Interested DGH radiologists?

Every DGH radiologist?

Alternative?

Perfusion scanning

CT or MR

Make decisions based on physiology

Reichenbach et al AJNR 20 1999

45 yr old, large ophthalmic aneurysm

Perfusion during occlusion

Tissue Classification

Advantages of Physiology

No false positives

Treat only those with viable tissue

Use as triage: a tool to spare the expert in stroke?

Radiology will enthusiastically

support acute stroke

Give us the tools to do it

Help us with the out of hours reporting

Bear in mind we have other responsibilities too:

Most radiologists cover all emergencies, not just neuro

And there are not many of us!

BUT

1. Plain scan only

Who reports?

Fear of onerous on call duty

Consultant radiologists ideal

In each hospital?

Network in Wales, or wider UK -

local/extended?

Network outside Wales?

Radiographer or stroke team report??

2. ASPECT scoreMore radiologist experience needed

Greater physician input

Give drug or not?

No longer a yes/no, now a maybe

Further need for experienced clinician

Use of the Alberta Stroke Program Early CT Score (ASPECTS) for Assessing CT Scans in Patients with Acute Stroke

AJNR Am J Neuroradiol 22:1534 ﾐ 1542, September 2001 . Alternatively, what percentage of the MCA territory is low density?

2. ASPECTS score reporting

Need consultant radiologist

In house

local

network

outsource

3.Assess other pathology

Need consultant radiologist

As before

4. Perfusion data

Need Neuroradiologist

or highly specialised other person

this may change in the future, but not yet

Similar issues with location

Suggestion:

All hospitals support IST3

Start slowly, learn where the problems are

Build resources based on local experience

Radiologist, radiographer, stroke team

Look to develop perfusion scanning, 24/7 services over time