MATHEMATICAL 3-DIMENSIONAL SOLID MODELING OF BIVENTRICULAR GEOMETRY

The characterization of regional myocardial stress distribution has be en limited by the use of idealized mathematical representations of biv entricular geometry. State-of-the-art computer-aided design and engine ering (CAD/CAE) techniques can be used to create complete, unambiguous mathematical representations (solid models) of complex object geometr y that are suitable for a variety of applications, including stress-st rain analyses. We have used advanced CAD/CAE software to create a 3-D solid model of the biventricular unit using planar geometric data extr acted from an ex vivo canine heart. Volumetric analysis revealed globa l volume errors of 4.7%, -1.3%, -1.6%, and -1.1% for the left ventricu lar cavity, right ventricular cavity, myocardial wall, and total enclo sed volumes, respectively. Model errors for 34 in-plane area and circu mference determinations (mean +/- SD) were 5.3 +/- 6.7% and 3.8 +/- 2. 7%. Error analysis suggested that model volume errors may be due to op erator variability. These results demonstrate that solid modeling of t he ex vivo biventricular unit yields an accurate mathematical represen tation of myocardial geometry which is suitable for meshing and subseq uent finite element analysis. The use of CAD/CAE solid modeling in the representation of biventricular geometry may thereby facilitate the c haracterization of regional myocardial stress distribution.