For this purpose you can use following expression within your transformation:
<%# (CMS.CMSHelper.CMSContext.CurrentPageInfo.DocumentName.ToString() == Eval("MenuItemName").ToString() ? "curent page" : "not current") %>
It compares current document name with the value in the MenuItemName field. If they are equal the text after "?" sign is returned else you receive the text after ":". Please note it's only example, so you can adjust it to suit your needs.