Related Experiment Video
Updated: Jan 1, 2026
Murine Echocardiography of Left Atrium, Aorta, and Pulmonary Artery
Published on: February 20, 2017
Vascular Landmark-Based Method for Highly Reproducible Measurement of Left Atrial Appendage Volume in Computed
Andrew Schluchter1, Chelsea Jan1, Katherine Lowe1
1Departments of Bioengineering (A.S., C.J., K.L., D.M.V., F.C., E.R.M.), UC San Diego, La Jolla, CA.
Insights
A new method accurately defines the left atrial appendage (LAA) boundary using computed tomography, improving LAA function measurement for intervention planning and thrombogenic risk analysis.
Area of Science:
- Cardiology
- Medical Imaging
- Computational Anatomy
Background:
- Modern computed tomographic (CT) scanning enables 4-dimensional imaging of the left atrial appendage (LAA).
- Accurate measurement of LAA function and morphology is crucial for planning interventions like occlusion and assessing thrombogenic risk.
- A key challenge is establishing a reproducible boundary between the LAA and the left atrium.
Purpose of the Study:
- To develop and validate a reproducible method for defining the boundary of the left atrial appendage (LAA) using 4-dimensional computed tomography.
- To assess the interobserver and intraobserver variability in defining the LAA ostium.
- To establish the utility of this method for obtaining LAA metrics for clinical applications.
Main Methods:
- Retrospectively gated 4-dimensional CT data from 25 patients were analyzed.
- The LAA ostium was defined at multiple time points during the cardiac cycle by three observers.
- Reproducibility was assessed using intraclass correlation coefficients (ICCs) for interobserver and intraobserver measurements.
Main Results:
- The method successfully defined the LAA ostium in 92% of patients.
- High interobserver ICCs (0.984-0.990) and intraobserver ICCs (0.989-0.995) demonstrated excellent reproducibility.
- The overall ICC for all observations was 0.988, indicating high precision.
Conclusions:
- A stepwise classification method using vascular landmarks reliably defines the LAA ostium.
- This technique establishes a highly reproducible boundary between the left atrium and LAA.
- The method provides essential LAA metrics for procedural planning and functional assessment.
Background:
Modern computed tomographic scanning can produce 4-dimensional images of the left atrial appendage (LAA). LAA function and morphology can then be measured, to plan interventions such as occlusion and to evaluate LAA flow for thrombogenic risk analysis. A current problem here is defining a reproducible boundary between the LAA and the left atrium.
Methods:
This study used retrospectively gated 4-dimensional computed tomographic data from 25 implantation and coronary artery imaging patients. In each patient, the LAA ostium was defined at multiple time points during the RR interval. To examine the reproducibility of the definition of the LAA ostium, 3 observers analyzed all time frames in each patient 3 times. Five nonconsecutive time frames from each patient were then compared using intraclass correlation coefficients to quantify the precision of the method across patients. The correlation of LAA volumes for each time frame of each patient was determined across the different observers (interobserver) and within each observer's own data sets (intraobserver).
Results:
The method was successful in 92% of patients. Two-way random-effect, absolute-agreement, single-measurement intraclass correlation coefficients for interobserver measurements were 0.984, 0.990, and 0.988, with intraobserver intraclass correlation coefficients of 0.989, 0.989, and 0.995. The intraclass correlation coefficient of all observations was 0.988.
Conclusions:
Classification of the LAA ostium using a stepwise procedure identifying the coumadin ridge and 2 vascular landmarks in ECG-gated computed tomography provides a viable method of establishing a highly reproducible boundary between the atrium and LAA needed to obtain LAA metrics useful for procedure planning and measuring LAA function.
