In this work we focus on the detection of objects immersed in anisotropic media from boundary measurements. We propose a one-iteration algorithm based on the Kohn-Vogelius formulation and the topological gradient method. The inverse problem is formulated as a topology optimization one. A topological sensitivity analysis is derived for an energy like functional. The unknown object is reconstructed using a level-set curve of the topological gradient. The efficiency and accuracy of the proposed algorithm are illustrated by some numerical results.