Yes and most definitely NO. If you are in need of a cardiac CT angiogram, then yes, a 64 or 128 or million slice scanner would be far superior to our 16 slice scanner. Medicare accreditation even demands that facilities wishing to perform cardiac CT must use a 64 slice capable or better scanner. The theory is that if a scanner can cover a larger area of the heart with the fewest rotations in between heart beats, it would drastically reduce motion artifact and increase the detail of the fine blood vessels of the heart.
However, if you are one of the other 99.98% of the population, Medicare accreditation bodies state that a 4 slice or better scanner would do fine for routine body imaging, and that 16 slice or better is required for CT angiography of the body. Regardless of the number of slices or the manufacturer of the scanner, most routine body CT scan imaging is presented in 2 to 5 millimeter (mm) slice thickness, with 1 mm or thinner for small joint and angiography studies.
As for image quality, routine cross sectional images produced from one CT scanner to another, even from different manufacturers, is approximately the same, as image quality assessment is standardized throughout the industry.
So to sum up, unless you’re getting a very specialized CT heart study, there is absolutely no reason why you have to have a CT scan only using scanners offering higher slice counts.