The main observable components of coronal mass ejections (CMEs) are the core, cavity and the frontal structure (FS), which is the leading edge of the visible CME. The core of a CME is associated with an eruptive filament whose motion can be followed just from the solar surface. As a rule, the FS is visible in scattered white light (SOHO/LASCO) far from the CME origination site. In few cases in near-the-limb events, the FS was detected closer to the solar surface. However, it appears not possible to detect any manifestations of the FS in a reasonable proximity of the pre-eruptive filament localized on the sun far from the limb. The identification of the FS remains unclear. We propose a method to estimate parameters of the initial volume of a CME based on the comparison of measured height-time plots of its structural components with a self-similar solution of MHD equations describing the expansion of a CME.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html