Extracranial Arterial Imaging

Module details

Title

Extracranial Arterial Imaging

Type

Specialist

Module code

SPS129

Credits

10

Requirement

Compulsory

Aim of this module

This module provides trainees with the knowledge that underpins the third year specialist module in Vascular Science. It will provide trainees with the knowledge, understanding and practical skills to safely contribute to the diagnosis of extracranial vascular disease and provides the knowledge that will underpin learning in the work base.

Competencies

#	Learning outcome	Competency	Action
# 1	Learning outcome 1	Competency Triage requests for investigation of patients with suspected carotid and vertebral artery disease.	Action View
# 2	Learning outcome 1	Competency Set up equipment and room ready for extracranial investigation.	Action View
# 3	Learning outcome 2	Competency Control infection risks associated with extracranial investigations in accordance with departmental protocols.	Action View
# 4	Learning outcome 2	Competency Minimise risks and hazards during the extracranial investigation in compliance with health and safety policies.	Action View
# 5	Learning outcome 2	Competency Explain the procedure to the patient, address any procedure-related questions they may have and provide information on how the patient will be informed of the results.	Action View
# 6	Learning outcome 2	Competency Gain informed consent for the extracranial investigation.	Action View
# 7	Learning outcome 2	Competency Obtain clinical history from the patient pertinent to the extracranial examination.	Action View
# 8	Learning outcome 3	Competency Perform an ultrasound scan using B Mode to identify normal carotid and vertebral anatomy in the neck.	Action View
# 9	Learning outcome 3	Competency Perform an ultrasound scan using colour Doppler and spectral Doppler to demonstrate the haemodynamics of normal carotid and vertebral arteries.	Action View
# 10	Learning outcome 3	Competency Perform an ultrasound scan to identify significant carotid artery disease.	Action View
# 11	Learning outcome 3	Competency Perform an ultrasound scan to identify an incidental finding, e.g. vertebral artery stenosis, other unusual finding.	Action View
# 12	Learning outcome 4	Competency Produce an interpretive report of investigations.	Action View
# 13	Learning outcome 4	Competency Recognise the pitfalls and limitations of the investigation.	Action View
# 14	Learning outcome 4	Competency Ensure extracranial results are given in a timely manner with appropriate action for urgent findings.	Action View

Assessments

You must complete:

• 2 case-based discussion(s)
• 2 of the following DOPS/ OCEs:

Perform and analyse B Mode colour Doppler scan of the carotid arteries obtaining longitudinal and transverse images from the origin of the CCA to the distal ICA and distal ECA.	DOPS
Perform and analyse B Mode colour Doppler scan of the carotid bifurcation using anterior, lateral and posterior approaches.	DOPS
Obtain, measure, differentiate and analyse Doppler spectra from CCA, ICA and ECA	DOPS
Obtain, measure and analyse Doppler spectra from vertebral and subclavian arteries.	DOPS
Perform and interpret a complete diagnostic scan on a new TIA patient	DOPS
Perform and interpret a complete diagnostic scan on a pre endarterectomy patient or follow up patient with known 70 percent diameter reduction stenosis.	DOPS
Perform and interpret a complete follow up scan on a post endarterectomystent patient.	DOPS
Perform and interpret a complete diagnostic scan on an immobile patient in a wheelchair	DOPS
Perform and interpret a complete diagnostic scan on an immobile patient on a trolley bed.	DOPS
Perform and interpret an emergency post endarectomy stent scan on a patient in recovery ICU using a portable system	DOPS
Introduce yourself to the patient and confirm their identity	OCE
Explain the carotid scan procedure and purpose to the patient	OCE
Obtain patient consent for the carotid scan	OCE
Obtain the relevant clinic history and symptoms pertinent to the carotid scan.	OCE
Prepare and position a mobile patient for the carotid scan	OCE
Prepare and position a patient with mobility difficulties for the carotid scan	OCE
Communicate with the patient during the scan to explain the practical aspects of the procedure e.g. head position.	OCE
Explain temporal tap procedure to the patient.	OCE
Explain the carotid scan findings to the patient	OCE
Explain what happens with the carotid scan results	OCE

Learning outcomes

1. Triage requests for investigation of patient with suspected carotid and vertebral artery disease and prepare the room and equipment.
2. Prepare patients and take their clinical histories.
3. Perform scans on patients with suspected carotid and vertebral artery disease.
4. Interpret, explain and report results.

Learning outcomes

1. Recognise and identify normal and atypical extracranial vascular anatomy and pathology.
2. Explain the normal haemodynamics and physiology of the extracranial vasculature and evaluate the numerous effects of pathology on blood flow.
3. Describe the clinical use of ultrasound in the diagnosis of extracranial disease, the linkages with other imaging techniques and the clinical importance in selecting the appropriate technique for the best management of the patient. 
4. Recognise the diversity and urgency of presenting signs and symptoms, and critically evaluate expected underlying haemodynamics and pathology.
5. Recognise the expected co-morbidity associated with extracranial vascular disease and the health and safety risks during the investigation
6. Explain the infection risks associated with vascular ultrasound and cerebrovascular patients and how they are managed.
7. Describe the principles and consequences of the National Stroke Strategy and the impact this has on diagnostic vascular services and patient management. 
8. Interpret extracranial ultrasound images, associated spectral data and measurements. Critically evaluate the need to select appropriate grading criteria and plaque characterisation tools for the appropriate interpretation of the data.
9. Explain and critically evaluate the need to convey complex scientific information to inform multidisciplinary teams of the diagnostic results, conclusions and consequences, in clear reports or presentations, in a clinically appropriate time frame.

Indicative content

Overview of cerebrovascular disease

• Anatomy of extracranial and intracranial circulation
  • Brachiocephalic artery
  • Subclavian artery
  • Common carotid artery
  • External carotid artery (and cervical branches)
  • Internal carotid artery
  • Ophthalmic artery
  • Middle cerebral artery
  • Posterior cerebral artery
  • Anterior cerebral artery
  • Circle of Willis
  • Vertebral artery
  • Basilar artery
  • Morphologic variations of the cerebrovascular circulation
  • Collateral pathways
• Pathology
  • Carotid atheroma and plaque
  • Aneurysms
  • Dissection
  • Carotid body tumours
  • Arteritis
  • AV malformations
  • Acute thrombosis
• Haemodynamics of the extracranial arteries
  • Carotid arteries
    • Flow in a bifurcation
    • Boundary layer separation
    • Effect of pathology on flow
      • Relationship between velocity, flow and lumen size
      • Proximal ICA stenosis
      • Distal ICA occlusion/stenosis
      • Stump syndrome
      • Common carotid occlusion
      • Brachiocephalic disease
    • Vertebral arteries
      • Patency
      • Flow direction/steel syndrome
        • Latent, transient, permanent steel
• Presenting signs and symptoms
  • Stroke/transient ischaemic attack
    • Hemiplegia, hemiparesis, hemisensory deficit
    • Visual disturbances
      • Transient monocular blindness
      • Retinal emboli
      • Homonymous hemianopia
    • Speech problems
      • Dysphasia – expressive/receptive
      • Aphasia
      • Dysarthria
    • Horner’s syndrome
    • Non-focal symptoms (syncope, vertigo, ataxia, amnesia, confusion)
    • Carotid bruit (asymptomatic/symptomatic)
  • Associated co-morbidity and risk factors
  • Investigative techniques
    • Ultrasound
    • MRA
    • Angiography
    • CT angiography (CTA)
  • Interpretation and measurement of stenosis (ECST, NASCET)
  • Treatment
    • Medical management
    • Carotid endarterectomy
    • Carotid stenting
  • The National Stroke Strategy

Ultrasound investigation of the extracranial arteries

• Historical perspectives and criteria developments
• Extracranial examination technique
  • Risk assessment and infection control
  • Patient preparation
  • Explanation of test
  • History taking
  • Patient positioning
• Scanning procedure and protocol
• Interpretation and determination of disease severity
  • B-mode imaging interpretation
    • Estimation of stenosis based on B-mode imaging
  • Colour Doppler imaging interpretation
    • Estimation of disease based on Colour duplex imaging
  • Determination of disease severity using Doppler spectral analysis
    • Peak systolic velocity, end systolic velocity and %stenosis
  • The role of power Doppler
  • External carotid artery disease
  • Consensus on diagnostic criteria for grading carotid artery disease
  • Ultrasonic characterisation of carotid plaques
    • Plaque classification
      • Anechoic
      • Echolucent
      • Echogenic
      • Hyperechoic
  • Plaque composition
    • Homogeneous
    • Heterogeneous
  • Plaque surface contour
    • Smooth
    • Irregular
    • Ulceration
  • Gary-Weale/Lusby plaque classification
  • Correlation with histology
  • Natural history studies
  • Prospective studies
• Accuracy of duplex scanning in the detection of carotid disease
• Limitations, equivocal data, artefacts, conflicts and pitfalls
  • Poor cardiac output
  • Compensatory flow
  • High bifurcation
  • Proximal or distal disease
  • Occlusion vs sub-occlusion

Activities

• Identify a patient with a carotid artery disease requiring surgery and, with permission, follow the progress of the patient from the initial consultation through investigation, surgical intervention and the follow-up appointment and reflect on your learning from this process.
• Identify two patients with a carotid artery disease requiring surgery and critically reflect on the effect on the lifestyle of the patient and the role of the healthcare scientist in the diagnosis and treatment of patients.
• Observe a series of patients reviewed as new and follow-up patients and critically appraise the process of referral, diagnosis and treatment, including the range of healthcare professionals who contribute to the care of each patient and how the interprofessional team works together.
• Take part in a multidisciplinary meeting and reflect on the way the multidisciplinary team contributes to the care of patients with disorders of the cerebrovascular system.
• Prepare a portfolio of case studies and images from a series of volunteers or patients that demonstrate the normal characteristics of carotid and vertebral arteries on B Mode, colour Doppler and spectral Doppler including any variations in anatomy.
• Critically appraise the role of B Mode, colour Doppler and spectral Doppler in the assessment of carotid and vertebral arteries and reflect on the effect technique and probe positioning have on the images. A portfolio of evidence should include images and spectra obtained from the a variety of segments (e.g. common carotid artery origin, carotid bifurcation, internal carotid artery, external carotid artery, vertebral artery, subclavian artery) and clearly demonstrate the relationship with other structures used as landmarks (e.g. the thyroid, the internal jugular vein) and the effects of probe positioning (e.g. anterior or posterior positions).
• Prepare a portfolio of case studies and images from a series of patients that demonstrate a range of carotid artery stenoses (e.g. mild atheroma, 50% stenosis, >70% stenosis, >90% stenosis, occlusion).
• Critically appraise the role of B Mode, colour Doppler and spectral Doppler in the diagnosis of carotid artery disease and reflect on how these modes are utilised together to establish a diagnosis (e.g. plaque echogencity, colour filling, shape of flow waveforms). A portfolio of evidence should include images and spectra obtained from a variety of carotid artery stenoses (e.g. mild atheroma, 50% stenosis, >70% stenosis, >90% stenosis, occlusion) from a series of patients and clearly demonstrate the presence of carotid artery disease.
• Reflect on each patient’s response to their diagnosis.
• Prepare a portfolio of case studies and images from patients with incidental findings (e.g. vertebral artery disease, subclavian disease, thyroid pathology).
• Critically appraise the relevance of reporting incidental findings and reflect how these affect the patient’s treatment. A portfolio of evidence should include images obtained from an incidental finding.
• Keep a portfolio/logbook of all clinical scans performed/observed, noting challenges and risks encountered with reflections on learning achievements.