A method identifying a wellbore volume change while drilling a subterranean wellbore includes acquiring first and second axially spaced pressure measurements in the wellbore. The wellbore volume change may include, for example, a borehole washout or a borehole pack-off. The pressure measurements may then be processed to obtain an interval density of drilling fluid between the measurement locations. A tool string including a large number of axially spaced pressure sensors (e.g., four or more or even six or more) electronically coupled with a surface processor via wired drill pipe may be used to obtain a plurality of interval densities corresponding to various wellbore intervals. The interval densities may be measured while drilling and may be further evaluated as an indicator of a wellbore volume change.