A NEW METHOD FOR THE MODEL-INDEPENDENT ASSESSMENT OF THICKNESS IN 3-DIMENSIONAL IMAGES

Three-dimensional (3-D) structural parameters derived from lower-dimen sional measurements using indirect morphometric methods may be strongl y biased if the measured objects deviate from the assumed structure mo del. With the introduction of 3-D microscopic measuring techniques it is possible to obtain a complete depiction of complex spatial structur es. As a consequence, new 3-D methods have recently been developed for the estimation of morphometric parameters such as volume, surface are a and connectivity by direct processing of the 3-D images, Structure t hickness is an important morphometric parameter which is usually defin ed for specific structure models only, In this paper we propose a gene ral thickness definition for arbitrary structures allowing us to calcu late the mean structure thickness and the thickness distribution of 3- D objects in a direct way and independently of an assumed structure mo del. Additionally, an efficient implementation for the practical usage of the method is described using distance transformation, The new met hod is applied to trabecular bone structures measured with a 3-D micro -computed tomography system.