Hybrid frequency/time-domain modeling may be used to compute the synthetic transient response to an eddy-current pulse for use in a high-dynamic-range and efficient inversion method for pulsed-eddy-current pipe inspection tools. In accordance with some embodiments, frequency-domain response signals are computed for a plurality of frequencies and converted, by frequency-to-time-domain transformation, to a first synthetic transient response signal. A time boundary associated with an onset of spurious oscillations in the first synthetic transient response signal is then automatically determined, and a second synthetic transient response signal beginning at the determined time boundary is determined directly with a time-domain numerical technique. A portion of the first synthetic transient response signal ending at the time boundary may be combined with the second synthetic transient response signal.