A single-shot ultrashort pulse off-axis digital holography system is used to image details of an atomizing dodecane spray produced by a diesel common-rail injection system. This technique takes advantage of multiple scattering noise rejection accomplished by coherence filtering with ultrashort laser pulses (400 nm, 100 fs FWHM) while providing the 3D reconstruction capability unique to digital holography; furthermore, being single shot, it can capture transient early injection events in dynamic high-pressure sprays without any motion blur. The method allows the user to image a large portion of the spray with a single 100 fs pulse, and to then numerically focus on the features of interest. This paper presents results obtained after testing the technique on a diesel common rail fuel injection system to explore the suitability of this technique for imaging the optically dense region of high-pressure atomizing fuel sprays. The spray system includes a common rail fuel supply with a single-orifice Bosch LBZ injector housed in a pressure vessel capable of reaching pressures up to 40 bar and temperatures up to 650 degrees C. Dodecane or diesel fuel is injected at pressures up to 1700 bar. The results show that the technique is unaffected by thick windows, as well as by pressure and temperature gradients, and can image through optically dense environments where shadowgraph imaging fails. The system achieves an in-plane resolution of 30 mu m at a working distance of 30 cm, and can resolve ligaments and droplets that reside in depth planes several centimeters apart within the transient spray field.