Algorithm for Reconstructing a 3D Model of the Aortic Root Using Uniform Crushing of CT Images

The aim of the study was to develop a uniform crushing method to be used in reconstructing a computational grid for 3D models simulating transcatheter aortic valve implantation based on medical images (DICOM) and mathematical processing and then to compare this novel approach with the currently used polygon and CAD methods.

Materials and Methods. The method was developed using the clinical and imaging data of patient N., 68 years old, who underwent transcatheter aortic valve replacement. The images were taken from multispiral computed tomography. The aortic root models were reconstructed using three methods: the polygons method (Mimics, Belgium), the CAD method (NX 9.0, Germany) and the author’s algorithm implemented in MATLAB (USA). Quality assessment of the reconstructed models was performed by numerical simulation using the Abaqus/CAE 6.14 (USA) engineering analysis reproducing two pressure load scenarios: the systole and the diastole.

Results. Evaluation of the reconstructed models of the aortic root showed that the proposed numerical method allows one to segment the object (aortic root) into elements, which are more homogeneous as compared to the polygon method or the CAD method. Thus, in the polygon method, 128,452 tetrahedrons (pyramids, C3D4) were used; in the CAD method, 28,456 hexahedrons (parallelograms, C3D8) were used; and in the case of the numerical method — 24,644 identical C3D8 elements were used. The results of the numerical simulations also differed: in the polygon method, the von Mises maximum was 0.262 MPa; for the CAD algorithm, 0.412 MPa; and in the numerical method, 0.359 MPa. An important criterion of the reconstruction efficiency was the computation time factor: for the polygon method, it was 458.6 s, for the CAD algorithm — 377.2 s (21.5% less), and for the proposed numerical method — 341.8 s (34.1% less).

Conclusion. The qualitative and quantitative results of the study demonstrate the usefulness of the proposed algorithm based on hexahedral finite elements in reconstructing a biological object for the purpose of numerical analysis. Using this algorithm in the transcatheter aortic valve implantation modeling process makes it possible to reduce the time of numerical analysis and increase its accuracy, which may improve the quality of preoperative planning.

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Klyshnikov K.U., Ovcharenko E.A., Ganyukov V.I., Tarasov R.S., Kokov A.N., Barbarash L.S. Algorithm for Reconstructing a 3D Model of the Aortic Root Using Uniform Crushing of CT Images. Sovremennye tehnologii v medicine 2018; 10(4): 7, https://doi.org/10.17691/stm2018.10.4.01