Okay, I'll respond to the argument. I can be wrong, too - but when I order a plain-vanilla CT, often, the first two sentences of the report are often (seriously) "The lack of oral contrast limits evaluation of the hollow organs. The lack of IV contrast limits evaluation of the solid organs." Maybe we do need some non-curmudgeon radiologists. Combine that with Old Mil's statement above, and its easy to imagine a situation where you have to answer the question "Why didn't you use contrast when ordering the scan, doctor?" The answer can't be: "Well, to keep the throughput times down." And yes, I have seen bouncebacks where the second, contrasted study reveals the pathology at least a few times. Maybe the disease hadn't fully presented itself fully. I'll have to keep these things in mind as I move forward.
I'll say this. I play golf regularly with my radiologist at one of my job sites and we frequently discuss matters like this. His bone to pick is CT/LP for SAH, in particular - but the sentiment in general related to me (his words) is: "Rusted.... when you CAN use contrast, DO use contrast. The study will be of better quality."