TransThoracic Ultrasound for Descending Aortic Aneurysms (THORUS)

Feasibility, Accuracy and Reproducibility of Ultrasound in Aneurysms of the Descending Thoracic Aorta

The goal of this observational study is to assess the applicability of non-invasive ultrasound in aneurysms of the descending thoracic aorta.

The main question it aims to answer is:

What is the feasibility of Ultrasound to visualise the Descending Thoracic Aorta, and can this imaging modality accurately measure the maximum size of aneurysms and residual sacs with acceptable reproducibility?

Participants are having their diagnosis confirmed or excluded by conventional imaging techniques (CT scans). Participants receive exactly the same standard of care regardless of their participation. The study offers an additional ultrasound scan, and the results will be compared with previous imaging.

Study Overview

• Status: Not yet recruiting
• Conditions: Feasibility; Ultrasound; Accuracy; Descending Aortic Aneurysm; Reproducibility

Detailed Description

Aneurysms of the aortic artery are a significant public health issue. The number of newly diagnosed aneurysms of the thoracic aorta is on the rise, and aneurysm rupture is a catastrophic event associated with high mortality rates. The most proximal sections of the aorta (ascending and the aortic arch) are routinely scanned by echocardiography practitioners. The abdominal aorta is also easily visualised on transabdominal ultrasound, and there is a screening programme in the UK that is highly cost-effective and reduced the aneurysm-related number of deaths. However, the portion of the aorta in the chest (descending thoracic aorta) is not routinely assessed by ultrasound practitioners.

The diagnosis of descending thoracic aneurysms relies mostly on imaging techniques that use ionising radiation. In addition, these techniques are expensive and may not be widely available in some regions. In contrast, ultrasound is a non-invasive technique that allows visualisation of most parts of the body. Ultrasound machine suppliers have invested in better systems and transducers over the years and visualisation of the descending thoracic aorta may now be possible.

The main aims of this study are to assess the feasibility (Part 1), accuracy (Part 2) and reproducibility (Part 3) ultrasound in the diagnosis and monitoring of descending thoracic aortic aneurysms. Participants will be recruited from the vascular lab and outpatient clinics, and diameters of the descending thoracic aorta will be measured with non-invasive ultrasound. Data obtained from study measurements will be compared with computed tomography scans that patients had as part of their standard of care.

If the feasibility, accuracy and reproducibility of Ultrasound are clearly demonstrated, routine ultrasound scans of the descending thoracic aorta may be suggested.

• Study Type: Observational
• Enrollment (Estimated): 60

Contacts and Locations

• Study Contact: Name: Carlos Pinho, PhD Student; Phone Number: +44 20 3312 3374; Email: cv1026@ic.ac.uk
• Study Contact Backup: Name: Cheuk Fund Wong; Phone Number: +44 20 7594 9832; Email: rgit@imperial.ac.uk

Study Locations

• United Kingdom
  • London
    • London, London, United Kingdom, W2 1NY
      • Imperial College Healthcare NHS Trust - St Mary's Hospital
      • Contact: Carlos Pinho, PhD Student; Phone Number: +44 20 3312 3374; Email: cv1026@ic.ac.uk
      • Contact: Cheuk Fund Wong; Phone Number: +44 20 7594 9832; Email: rgit@imperial.ac.uk
      • Principal Investigator: Carlos Pinho, PhD Student

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

All Participants will receive a single Ultrasound scan as part of this study. All Patients had at least one CT scan of the thoracic aorta prior to the study as part of their standard of care. No additional radiation or invasive imaging techniques will be used in the Thorus study. The data obtained from the CT will be analysed by an independent reviewer and compared with Ultrasound measurements. Participants will be recruited prospectively from a single NHS Trust in London - Imperial College Healthcare NHS Trust.

Description

Inclusion Criteria:

• Patients with diagnosed AAA or other vascular condition attending the vascular scanning department for routine ultrasound and confirmed healthy DTA (Control group).
• Patients with known DTAA (including Type B dissection) or patients who had TEVAR previously (Case group).
• Patients who have had CT as part of their standard of care.
• Patients able to tolerate the scan (Lying in supine position).
• Adults aged 18 or over.
• Willing to provide consent.

Exclusion Criteria:

• Patient under 18 years of age.
• Previous thoracic surgery or body deformity (severe kyphosis, scoliosis, pleural effusion or chest wall trauma).
• Patients without previous imaging of the thoracic aorta.
• Life expectancy <2 years.
• Pregnant Women.
• Patients unwilling to provide consent or unable to comply with study requirements.
• Patients too frail to travel to routine outpatient appointments.
• Inability to attend the appointment due to time constraints or other commitments.
• Although rare, ultrasound contraindications as described in the scanning protocol are also exclusion criteria.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
CONTROLS; Patients with healthy DTA (30 patients)
CASES; Patients with DTAA or TEVAR (30 patients)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part 1 - Feasibility - Proportion of participants with successful ultrasound measurement of the diameter of the descending thoracic aorta	Number and percentage of participants in whom the descending thoracic aortic diameter can be obtained by transthoracic ultrasound. The units of Measure are total number and percentages.	Day 1 - At the single ultrasound study visit.
Part 1 - Feasibility - Length of the descending thoracic aorta by Ultrasound	Total length of the descending thoracic aorta from the aortic isthmus to the coeliac axis. The unit of Measure is Centimetres (cms).	Day 1 - At the single ultrasound study visit.
Part 1 - Feasibility - Ultrasound Quality Score	Number of ultrasound windows that allow visualisation of the descending thoracic aorta (0 to 3 windows) and allocation of a quality score. The Unit of Measure is a score created for this study (0-Windows: No views; 1 window: Poor; 2 windows: Moderate; 3 windows: Good). Higher scores mean better image quality.	Day 1 - At the single ultrasound study visit.
Part 2 - Accuracy - Comparision between Transthoracic Ultrasound and CT	Calculate mean differences and limits of agreement between TUS and CT. Achieve high sensitivity and specificity.	Day 1 - At the single ultrasound study visit.
Part 3 - Reproducibility - Intraclass correlation coefficient	Calculate inter- and intra-operator variability by intraclass correlation coefficient (ICC). The study aims to achieve good or excellent reliability.	Day 1 - At the single ultrasound study visit.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part 1 - Feasibility - Factors limiting visualisation of the Descending Thoracic Aorta	Number and percentages of participants in whom limiting factors such as body habitus or rib shadowing are reported after the ultrasound test. The units of measure are the number of participants with raised BMI (kg/m^2) and acoustic shadowing due to bone density.	Day 1 - At the single ultrasound study visit.
Part 1 - Feasibility - Duration of Ultrasound Examination	Total time needed to complete the ultrasound scan of the descending thoracic aorta. The unit of measure is minutes.	Day 1 - At the single ultrasound study visit.
Part 1 - Feasibility - Patient Feedback Questionnaire	Scores are obtained from the patient feedback questionnaire that was created specifically for this study and consists of 5 questions relating to comfort, tolerability and overall experience of the ultrasound scan. The unit of measure is a score ranging from 1-Strongly Disagree to 5-Strongly Agree. Higher scores mean better patient satisfaction.	Day 1 - At the single ultrasound study visit.

Collaborators and Investigators

• Sponsor: Imperial College London
• Investigators: Study Chair: Professor Colin Bicknell, Imperial College London

Study record dates

Study Major Dates

• Study Start (Estimated): September 7, 2026
• Primary Completion (Estimated): April 5, 2027
• Study Completion (Estimated): April 3, 2028

Study Registration Dates

• First Submitted: July 28, 2026
• First Submitted That Met QC Criteria: August 3, 2026
• First Posted (Actual): August 7, 2026

Study Record Updates

• Last Update Posted (Actual): August 7, 2026
• Last Update Submitted That Met QC Criteria: August 3, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 199470; IRAS Project ID: 365629 (Other Identifier: NHS Health Research Authority)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Sharing IPD is not required to answer the research question.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No