Measuring the abdominal aorta with ultrasonography and computed tomography - difference and variability

Area of Science:

• Radiology
• Medical Imaging
• Vascular Surgery

Background:

• Accurate measurement of aortic diameter is crucial for diagnosing and monitoring abdominal aortic aneurysms (AAAs).
• Ultrasonography (US) and computed tomography (CT) are common imaging modalities used for this purpose.
• Understanding the agreement between US and CT is essential for consistent clinical management.

Purpose of the Study:

• To evaluate the agreement between US and CT in measuring aortic diameters.
• To assess differences in anteroposterior (AP) and transverse (TR) measurements.
• To analyze agreement in subjects with and without abdominal aortic aneurysms (AAAs).

Main Methods:

• Sixty-one subjects were included: 33 with AAA (diameter >30mm) and 28 without (diameter <30mm).
• Measurements of AP and TR aortic diameters were compared between US and CT.
• Statistical analysis focused on differences and variability between the two imaging modalities.

Main Results:

• In non-aneurysmal aortas, US yielded larger AP (2.8mm) and TR (3.8mm) diameters compared to CT.
• In AAA cases, the mean diameter measurements did not significantly differ between US and CT.
• Expected 95% differences were <5.7mm (AP) and <7.6mm (TR) for non-aneurysmal aortas, and <8.0mm (AP) and <10.6mm (TR) for aneurysmal aortas.

Conclusions:

• Agreement between US and CT for aortic diameter measurement varies based on aortic size and measurement orientation.
• The observed differences have implications for clinical decision-making and research protocols.
• Standardization of measurement techniques may be necessary to improve inter-modality consistency.