Statistical Shape Clustering of Left Atrial Appendages

Jakob Mølkjær Slipsager, Kristine Aavild Juhl, Per E. Sigvardsen, Klaus F. Kofoed, Ole De Backer, Andy L. Olivares, Oscar Camara, Rasmus Reinhold Paulsen

Research output: Chapter in Book/Report/Conference proceedingBook chapterResearchpeer-review


Fifteen percent of all strokes are caused by emboli formed in the left atrium (LA) in case of atrial fibrillation (AF). The most common site of thrombus formation is inside the left atrial appendage (LAA). The LAA is accounting for 70% to 90% of the thrombi formed in the LA in patients with non-valvular AF. Studies have shown there is a correlation between the LAA morphology and risk of ischemic stroke; Chicken Wing and Cauliflower LAA shapes are associated with lower and higher risk, respectively. These two LAA shape categories come from a popular classification in the medical domain, but it is subjective and based on qualitative shape parameters. In this paper, we describe a full framework for shape analysis and clustering of the LAA. Initially, we build a point distribution model to quantitatively describe the LAA shape variation based on 103 LAA surfaces segmented and reconstructed from multidetector computed tomography volumes. We are successfully able to determine point correspondence between LAA surfaces, by non-rigid volumetric registration of signed distance fields. To validate if LAA shapes are clustered, we employ an unsupervised clustering on the shape models parameters to estimate the natural number of clusters in our training set, where the number of shape clusters is estimated by validating the test log-likelihood of several Gaussian mixture models using two level crossvalidation. We found that the LAAs surfaces basically formed two shape clusters broadly corresponding to the Chicken wing and non-Chicken Wing morphologies, which fits well with clinical knowledge.
Original languageEnglish
Title of host publicationStatistical Atlases and Computational Models of the Heart
Publication date2019
ISBN (Print)978-3-030-12028-3
Publication statusPublished - 2019
EventSTACOM 2018: Statistical Atlases and Computational Modeling of the Heart workshop - Granada Exhibition and Conference Centre, Granada, Spain
Duration: 16 Sep 201816 Sep 2018


ConferenceSTACOM 2018
LocationGranada Exhibition and Conference Centre
Internet address
SeriesLecture Notes in Computer Science


  • Left atrial appendage
  • Point distribution models
  • Clustering
  • Gaussian mixture models

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