Optimal scan planning with statistical shape modelling of the levator ani

Abstract

Defective pelvic organ support is one of the most common problems in women and its intervention requires an accurate preoperative identification of prolapsed organs and their mechanical properties. With the current state-of-the-art in magnetic resonance imaging, 3D dynamic imaging of the pelvic floor is prohibited by the maximal temporal resolution that can be achieved. In this paper, we propose an optimal scan-planning approach based on statistical shape modelling of the levators such that only a limited number of 2D imaging planes are needed to recover the entire 3D structure. The statistical shape model was achieved by the use of harmonic shape embedding and modelling whilst the reconstruction of the 3D structure from selected imaging planes was carried out by the incorporation of a conjunct MDL measure indicating the statistical shape variation captured by respective imaging planes. The value of the proposed technique was demonstrated with data acquired from a group of 11 asymptomatic subjects, highlighting the value of the method in studying dynamic shape changes when complete 3D imaging is impractical. © Springer-Verlag Berlin Heidelberg 2003.