1. A computer-implemented method for processing and displaying breast x-ray tomosynthesis information, comprising: receiving a plurality of two-dimensional breast x-ray tomosynthesis reconstructed image slices corresponding to a respective plurality of slice depths in a breast volume; receiving a plurality of computer-aided detection (CAD) findings associated with the breast volume, each CAD finding identifying a subset of the image slices spanned by a suspected anatomical abnormality and locations therein of the suspected anatomical abnormality; displaying on a user display a two dimensional diagnostic image comprising either (i) a single one of said received image slices, or (ii) a plurality of depthwise adjacent ones of said received image slices slabbed together, the diagnostic image thereby being characterized by an image depth and an image thickness; displaying on the user display in visual proximity to the two dimensional diagnostic image a graphical depth navigation tool configured to graphically communicate to a user said image depth and said image thickness and to allow user control thereof, the graphical depth navigation tool comprising: (a) a slice ruler spatially extending in a first direction representative of said image depth, said slice ruler comprising individual markers representing an image slice contained in the breast volume, and (b) an extent indication region identifying a location and extent of each marked CAD finding of the breast volume, the extent indication region comprising: a plurality of CAD indicator icons corresponding to respective CAD findings and running near and along said slice ruler, each CAD indicator icon spanning a contiguous segment that corresponds in depthwise position and extent to the subset of image slices spanned by the associated CAD finding, and at least one single-slice highlighting mark positioned on an associated CAD indicator icon at a location indicative of the slice depth of a respective one of the subset of image slices spanned by the associated CAD finding that contains viewable image information corresponding to that associated CAD finding, and (c) a slice slider icon disposed along said slice ruler at a user-controllable position corresponding to said image depth, said slice slider icon comprising a thickness indicator extending along a distance of the slice ruler corresponding to a thickness of the suspected anatomical abnormality identified by a CAD finding, wherein a current location of said slice slider icon and a size of said thickness indicator are automatically adjusted to correspond to a currently selected CAD finding.