The article/headline is confusing; the real comparison is between a non-invasive PET-CT scan using metomidate as an imaging medium, and invasive and specialized adrenal vein sampling (AVS), both as diagnostic tools.
AVS is correlated using a non-metomidate adrenal CT scan anyway, so a CT-only option would be less expensive and could be performed in more facilities, making it more accessible:
> Until now, 99% are never diagnosed because of the difficulty and unavailability of tests.
And since AVS has such a low predictive success rate (63% per the study), the CT-scan-only alternative doesn't even have to be good, it just has to be about as bad as AVS.
The results of either could very well be "keep taking meds for 40 years" or "surgery helps immensely", but the real cost savings are in avoiding AVS and also potentially diagnosing and treating more people sooner.
(Also mind that the study's done in the UK, where CT scans cost patients about £800/US$1,000 even when done privately, and in Scotland/Wales/N. Ireland the meds are free to the patient. In the US, a CT scan averages about $5,000, $12,000 isn't unheard of, and the meds cost $7,000-$20,000 for 40 years.)