2011 Winter Project Week:ParticleShapeAnalysis

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Motivations: Clinical Applications in Orthodontics

We are aiming to develop methods to compute Shape Correspondence and Shape Analysis to the Orthodontic Clinical field. The main challenge in this approach is the complexity of the surfaces processed, i.e. Cranio-Maxillo-Facial anatomy. Until now, correspondence was obtained almost entirely for brain morphometry studies. SPHARM-PDM Toolbox has been used until now for different Ortho applications ([1-5] ), however the performance of this methodological framework does not work satisfactorily for Full Mandibles. Our main interest focuses right now in Entropy-Based Particle Systems [6], that does not rely in parametric fields or spherical topology for establishing correspondence in a Surface Ensemble.

Particle systems performance in mandibles is not very good with the curent implementation. Correspondence in thin areas is ill-defined, and that causes a number of reconstruction problems (see figure 1). We think that acknowledging for particles normal directions in this application is necessary. For this we did several attempts to incorporate normal directions into particles, without interfering with the optimization process (see figure 2). Still those seem not to be enough and we have implemented some code to incorporate normal directions into the optimization.

Key Investigators

  • UNC SPHARM: Beatriz Paniagua, Martin Styner, Corentin Hamel, Lucile Bompard
  • UNC Particle System: Manasi Datar, Ross Witacker, Martin Styner, Beatriz Paniagua, Ipek Oguz, Clement Vachet
  • UNC Shape Analysis, Application and Visualization: Beatriz Paniagua, Martin Styner, Lucia Cevidanes



1. Integrate normal directions optimization code in ShapeWorks particle-optimization shape correspondence program, developed by Utah U., altogether with the code that acknowledges for geodesic distances from Manasi Datar and Ross Whitacker.

2. Meet with Joshua Cates to resolve coding questions regarding to the current implementation of ShapeWorks

3. Particle Correspondence in Slicer3: yes or no discussions

Approach Plan

1. Entropy-Based Particle Systems: Meet with Manasi Datar (Utah U.) to discuss integration of our code

2. Meet with Josh Cates in a Q&A session to figure out specific details

3. Attend discussions between Ross Whitacker and Steve Piper (?)


* On Tuesday 11th, we had a breakout meeting in which the next steps for the particle system development were decided:

- Manasi has to commit her work on geodesics distances and normal penalties.

- The whole Shape Works has to migrate from GForge (CVS) to NITRC (svn) - Clement will work with Josh

- Beatriz and Lucile will work into implementing a quality control module for Slicer3 in which the results of the correspondence obtained can be evaluated.

* Applying satisfactorily the recent upgrades (geodesics and normal penalty) to mandibular data (Jaws)



[1] LHS Cevidanes, B Paniagua, L De Paula, M Styner: Shape Analysis of Stability following Skeletal Class III Surgery. IADR Barcelona, July 14-17, 2010.

[2] B Paniagua, LHS Cevidanes, H Zhu, M Styner: Surgical Outc ome Quantification using SPHARM-PDM Toolbox. IADR Barcelona, July 14-17, 2010.

[3] D Walker, LHS Cevidanes, B Paniagua, H Zhu, M Styner, PF Lim: Validation of Shape Correspondence for Quantification of Condylar Resorption. J Dent Res. 2010 ;89 (Spec Iss A):1200.

[4] LHS Cevidanes, A Alhadidi, B Paniagua, M Styner, WR Proffit, J Ludlow, A Mol, E Russouw: 3D quantification of mandibular asymmetry. Submitted to Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology & Endodontics April 2010.

[5] LHS Cevidanes, AK Hajati, B Paniagua, PF Lim, DG Walker, G Palconet, AG Nackley, JB Ludlow, MA Styner, H Zhu, C Phillips. Quantification of Condylar Resorption in TMJ Osteoarthritis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod Oral Surg. Epub April 08 2010.

[6] J Cates, P T Fletcher, M Styner, M Shenton, R Whitaker. Shape Modeling and Analysis with Entropy-Based Particle Systems. Information Processing in Medical Imaging IPMI 2007, LNCS 4584, pp. 333-345, 2007.