We introduce a pixel-to-pixel comparison method to detect the temperature anisotropies on the Cosmic Microwave Background induced by the time variation of gravitational potentials along the line of sight. We demonstrate it to be more sensitive than the cross-correlation method used in previous studies. We compare the recent WMAP data with templates constructed from galaxy catalogues. A positive cross-correlation between both data sets will be a signature of an accelerated expansion of the Universe. Contrary to other authors, we fail to detect any signal, except those coming from foreground residuals. Either the effect of an accelerated expansion is not present on the WMAP data or the galaxy catalogues at present do not trace the evolution of the large scale gravitational field.