This study will test how well an artificial intelligence (AI) software called Aorta AIM measures the size of the aorta (the body's main blood vessel) from CT scans. The aorta can become enlarged over time, which may lead to serious health problems. Doctors need to measure the aorta accurately to monitor patients and decide on treatment.

Currently, doctors measure the aorta manually on CT scans, which takes time and can vary between different doctors. Aorta AIM is designed to measure the aorta automatically and consistently.

In this study, researchers will compare Aorta AIM's measurements to those made by experienced radiologists or cardiologists (doctors who specialize in reading medical images). The study will use CT scans that have already been taken as part of routine medical care - no additional scans or procedures are needed.

The study will include approximately 250 participants across multiple hospitals in Brazil and the United States. Participants will be adults who have had a chest or abdominal CT scan that shows their aorta.

The main goals are to:

• Check if Aorta AIM measures the aorta as accurately as radiologists
• See if Aorta AIM can help doctors work more efficiently
• Evaluate if the software works well in different hospital settings and with different types of patients

This research may help improve how doctors monitor aortic disease and make treatment decisions in the future. There are no risks to participants since the study only uses existing medical images.

• Adults ≥22 years at time of imaging

• Studies performed 1 Jan 2016 - 31 August 2025

• CT imaging of the whole, thoracic, or abdominal aorta, with or without contrast enhancement, acquired with any gating protocol (including non-gated)

• Slice thickness ≤ 3mm

• CT imaging in which truncation creates discontinuity within a targeted aortic region, preventing reliable diameter measurement (e.g., cardiac-focused CT acquisitions where an incomplete or absent aortic arch creates discontinuity between the aortic root and the descending thoracic aorta)

  o Partial aortic coverage is not grounds for exclusion. Where truncation affects individual regions, only those specific regions will be excluded from analysis; remaining fully captured regions will be retained for measurement.

• Metal implants <5cm from aorta (e.g. thoracic stent)

• Prior aortic surgery

• Severe motion artifacts (e.g. >3mm vessel blurring)

• Congenital aortic anomalies (e.g. coarctation, vascular rings)

• Post-traumatic aortic repairs

• The patient opted out of having their data used for medical research before the date of cross-referencing by the site team

Adult patients (≥22 years of age) who underwent CT imaging of the aorta (whole, thoracic, or abdominal) as part of routine clinical care between January 1, 2016 and August 31, 2025. CT scans must include imaging of the aorta with or without contrast enhancement and have slice thickness ≤3mm. Patients with metal implants within 5cm of the aorta, prior aortic surgery, severe motion artifacts, congenital aortic anomalies, or post-traumatic aortic repairs are excluded. Patients who opted out of having their data used for medical research are also excluded. Retrospectively collected, de-identified CT imaging data from approximately 250 cases across multiple international sites in the United States and Latin America will be analyzed.

This is a retrospective medical device validation study using de-identified CT imaging data. Individual participant data cannot be shared due to patient privacy protections, institutional data use agreements, and proprietary algorithm considerations. Aggregate study results, including device performance metrics and statistical analyses, will be made publicly available through peer-reviewed publication and regulatory submissions.