Reproducibility of ECG-gated ultrasound diameter assessment of small abdominal aortic aneurysms

Abstract

Objective: No standardised ultrasound procedure to obtain reliable growth estimates for abdominal aortic aneurysms (AAA) is currently available. We investigated the feasibility and reproducibility of a novel approach controlling for a combination of vessel wall delineation and cardiac cycle variation.

Design: Prospective comparative study.

Methods: Consecutive patients (N = 27) with an AAA, attending their 6-month control as part of a medical treatment trial, were scanned twice by two ultrasound operators. Then, all ultrasound recordings were transferred to a core facility and analysed by a third person. The AAA diameter was determined in four different ways: from the leading edge of adventitia on the anterior wall to either the leading edge of the adventitia (method A) or leading edge of the intima (method B) on the posterior wall, with both measurements performed in systole and diastole.

Result: Inter-operator reproducibility was ± 3 mm for all methods applied. There was no difference in outcome between methods A and B; likewise, end-diastolic measurement did not improve reproducibility in preference to peak-systolic measurement.

Conclusion: The use of a standardised ultrasound protocol including ECG-gating and subsequent off-line reading with minute calliper placement reduces variability. This may be of use in developing protocols to better detect even small AAA growth rates during clinical trials.