ACUTE STROKE IMAGING SURVEY

Imaging is essential for diagnosing and managing acute ischemic stroke. This survey was motivated by a desire to understand acute stroke imaging practices around the world. While identifying candidates for reperfusion therapies via multi-modal code stroke CT remains crucial, we have (across the 6 centres in which the survey authors practice) also witnessed a brisk growth in acute stroke imaging since the COVID-19 pandemic. Other such reports have emerged from groups worldwide, including the use of emergent multi-modal code stroke CT as a screening examination in patients despite absence of focal neurologic deficits.

In view of the intensive resource demands of such protocols we felt a formal survey of ordering practices and behavioural patterns in multi-modal code stroke CTs could serve as a timely starting point from which dedicated strategies could be contemplated to address this large and growing challenge in neuroimaging. As members of the neuroradiology community practicing at the coalface of emergent stroke imaging and under the mantra of ‘imaging wisely’, we are all heavily invested in the rational use of imaging.

We would greatly appreciate your input, and hope that you can make time in your busy schedules to take this anonymous survey. No personal data is collected, and your individual responses will remain confidential.

Thank you in advance!

Shalini, Dylan, Vivek, Seena and Roland

A. PLACE OF PRACTICE

2.In what setting do you predominantly work?

Academic Center

Community hospital

Privately owned hospital or network (non academic center)

Government hospital (non academic center)

3.What level of stroke centre is your practice (see definitions below)?

Comprehensive stroke centre

Definition:
A Comprehensive Stroke Centre provides the highest level of stroke care, including a comprehensive team of experts (vascular neurologists, neurosurgeons, neuroradiologists and vascular surgeons). CSC Certification requires hospitals to meet rigorous standards to deliver specialized care for the most complex stroke cases. A CSC must have the following: availability of advanced imaging techniques around-the-clock, including MRI, MRA, CTA, DSA and transcranial Doppler ultrasound; a team of personnel trained in vascular neurology, neurosurgery, and endovascular procedures, with around-the-clock access to these personnel, imaging, operating rooms, and endovascular facilities; ICU and neuroscience ICU facilities; experience and expertise in treating patients with large ischemic strokes and intracerebral hemorrhage.

Thrombectomy capable (but not a comprehensive stroke center)

Definition:
A Comprehensive Stroke Centre provides the highest level of stroke care, including a comprehensive team of experts (vascular neurologists, neurosurgeons, neuroradiologists and vascular surgeons). CSC Certification requires hospitals to meet rigorous standards to deliver specialized care for the most complex stroke cases. In addition to satisfying all the prerequisites for a PSC certification, CSCs must have the following: availability of advanced imaging techniques around-the-clock, including MRI, MRA, CTA, DSA and transcranial Doppler ultrasound; a team of personnel trained in vascular neurology, neurosurgery, and endovascular procedures, with around-the-clock access to these personnel, imaging, operating rooms, and endovascular facilities; ICU and neuroscience ICU facilities; experience and expertise in treating patients with large ischemic strokes and intracerebral hemorrhage.

Primary stroke centre

Definition:

Primary Stroke Centres represent the next level of stroke centre certification, which includes a dedicated interdisciplinary stroke team, access to advanced cerebrovascular imaging, and an inpatient stroke unit designed for the admission and care of patients with an AIS.

Acute stroke ready hospital

Definition:

Acute stroke-ready hospitals are equipped to perform rapid clinical stroke assessments, provide stabilization, and implement protocols for the safe administration of tPA. Following initial assessment and stabilization, patients are typically transferred to a more advanced stroke centre for further evaluation and advanced diagnostic procedures.

No acute stroke services available

I don't know

4.In which of the following patient groups is thrombectomy performed at your institution (select as many as apply):

Anterior circulation LVO (M1 segment MCA or ICA)

Posterior circulation LVO (basilar and vertebral)

M2 segment MCA

Other medium and distal occlusions (e.g. PCA, ACA, M3 or M4 segment MCA)

B. ACUTE STROKE IMAGING PROTOCOL

5.Do all patients presenting through the emergency department at your hospital with concern for acute ischemic stroke undergo the same stroke imaging protocol?

Yes

6.If you responded yes to question 6, what is your standard protocol?

NCCT head only

NCCT and CTA head and neck (single arterial phase)

NCCT and Multiphase CTA head and neck

NCCT, CTA head and neck and CTP

MRI brain (with or without MRA, MRP)

Other protocols not presented above

7.If you responded no to question 6, how are stroke imaging protocols determined?

Emergency medicine or neurology preference

American Heart Association/ American Stroke Association or equivalent local guideline-based exam thresholds for ordering CT perfusion or MRI studies

Radiologist driven protocol decisions based on provided history

Other

8.Is the protocol used in early window patients (presenting within 6 hours of symptom onset or last known well) different from that used in patients presenting in the late-window (at 6-24 hours)?

Yes

9.Does your emergency department have specific guidelines for ordering stroke protocol imaging?

Yes

10.If you answered yes to Question 9, are these guidelines strictly followed?

Yes

11.If you responded yes to Question 9, what factors determine the selected protocol?

NIHSS score

FAST or other pre-hospital scale

NA (responded no to question 10)

Other

12.Is a radiologist or a radiology resident routinely involved in the protocolling of these studies prior to performance

Yes

No - they are all automatically protocolled by the imaging technologist based on a “code stroke” initiation

No - they are automatically protocolled without human input based on the order set

No – the stroke team determine the protocol

13.Is a radiologist or a radiology resident routinely involved in the protocolling of these studies prior to their being performed?

Never

In selected cases where the diagnosis isn’t clear

Always

14.For patients with a high clinical suspicion of acute ischemic stroke, what is your institutional first-line (emergent) imaging protocol in the early thrombectomy window, i.e. within 6 hours of symptom onset or last known well?

NCCT head only

NCCT CT head and CTA head and neck (single arterial phase)

NCCT and Multiphase CTA head and neck

NCCT brain, CTA head and neck & CT Perfusion

MRI head

Other (please specify)

15.For patients with a high clinical suspicion of acute ischemic stroke, what is your institutional first-line imaging protocol in the late thrombectomy window, i.e. within 6-24 hours of last known well?

NCCT head only

NCCT head and CTA head and neck (single arterial phase)

NCCT head and Multiphase CTA head and neck

NCCT brain, CTA head & neck and CT Perfusion

MRI head

Other (please specify)

16.If you do emergent acute stroke MRI scans, how is the MRI safety screen performed?

Based on history provided by the patient or next of kin +/- electronic medical record

XR screening

NA (we do not perform emergent acute stroke MRI scans)

Other

17.If you do not routinely perform CT Perfusion in the late window, what is the reason? (you may select more than one option)

CT scanner does not have perfusion scanning capabilities

CT technologist staff are not trained to perform CTP

Radiologists are not trained to interpret CTP

It is too time consuming

Evidence is not sufficient to support necessity

Use of multiphase CTA instead

Use of MRI instead

NA, we routinely perform CTP

Other

18.First line imaging in acute ischemic stroke patients presenting beyond the thrombectomy window (i.e. later than 24 hours)

NCCT head only

NCCT head and CTA head and neck (single arterial phase)

NCCT head and Multiphase CTA head and neck

NCCT head, CTA head & neck and CT Perfusion

MRI head

C. TRANSFER PATIENTS

19.Does your hospital receive patients by transfer for acute ischemic stroke treatment?

Yes

20.If yes to Question 19, do you routinely re-image patients upon arrival?

Yes

Only if outside hospital imaging does not meet our institutional standard

Only for selected patients in whom additional information would guide treatment

21.If yes to Question 19, what standard protocol do you perform for transfer patients with acute ischemic stroke?

NCCT head only

NCCT and CTA head and neck (single arterial phase)

NCCT and Multiphase CTA head and neck

NCCT, CTA head and neck and CTP

MRI head (with or without MRA, MR Perfusion)

D. CLINICAL THRESHOLD FOR ACUTE STROKE IMAGING

22.Do you agree with the following statement “Emergent acute stroke imaging is appropriately utilized at my institution”

Strongly disagree

Disagree somewhat

Neither agree nor disagree

Agree

Strongly agree

23.Do you agree with the following statement “Emergent acute stroke imaging is overused at my institution”

Strongly disagree

Disagree somewhat

Neither agree nor disagree

Agree

Strongly agree

24.Has the clinical threshold for performing acute stroke imaging at your institution changed since 2020?

Yes, it has decreased (i.e. patients with milder symptoms are now being scanned)

Yes, it has increased

Please answer questions 21-25 if your institution performs emergent multimodal CT (i.e. NCCT brain, CTA head and neck +/- CT perfusion or multiphase CTA) as first-line imaging in acute ischemic stroke patients presenting within the thrombectomy window. If you perform MRI instead as first line imaging, please answer NA to these questions.

25.Most commonly, who does the clinical assessment, based on which the referral to emergent multi-modal acute stroke CT is made?

Emergency services (e.g. ambulance paramedic)

Emergency Department doctor

Neurointerventional service

Stroke Neurologist

Other (please specify)