64 or 128 slice Helical CT's give excellent images with albeit with a higher dose
FWIW I haven't looked thoroughly at the papers on calcium score in 5 years or more - but when I last looked there were a whole host of papers on how to use/prove out the multislice device to get a predictive result.
As for 99% - it actually is worrisome that the field is tending that way. Even the doc I know is focusing more on using more traditional CT scans for angiograms - something I would very much steer away from.