An imaging method positions a heterogeneous object within a fixture having a chamber. The fixture also has a valve for receiving a gas and normally sealing the chamber. Thus, the object is within the chamber. Next the method positions the fixture within an active region of a CT machine, fluidly connects a gas line to the valve, and injects an inert gas into the chamber through the gas line and the valve. The inert gas may include one or more of the xenon, argon, and krypton. The method then increases the pressure within the sealed chamber to increase the density of the gas within the chamber, and directs x-ray energy toward the active region of the CT machine to produce a plurality of two-dimensional images of the object and the pressurized gas. Finally, the method generates a three-dimensional representation of the object from the plurality of images.