Any method of detecting disease at an early stage before the subject is aware that it might be present must satisfy certain criteria: –
It must be safe and avoid harmful X-Rays or any other source of radiation
Any test must be painless and not cause any distress.
The results of any test must be unambiguous. The results should not require expert interpretation.
At the very least the test should be able to divide the subjects into three categories:
a) Come back in two years
b) Severe Disease go to your doctor
c) Results equivocal requiring restudy in say 6 months
If possible the results should be in a simple form that can be shown to the subject. There is no better way to get compliance with treatment or the imposition of strict preventive measures than the immediate impact of seeing the presence of disease whereas the remote risk of a future event caused by risk factors does not usually sufficiently reinforce the preventive message.
Ideally the test can be taken to the community rather than requiring subjects to come to a hospital.
The test and preventive measures should cost substantially less than the expensive management of end-stage disease and represent demonstrable savings to the healthcare budget.
X-ray techniques showed the lumen of vessels but not the vessel walls. Magnetic Resonance could be used to produce images of organs in the body but the problem was that imaging a moving organ such as the heart was much more complex than for static bone or organs.
It would require sophisticated computers with complex software and computers were relatively new, filled a small room and were extremely expensive. Computer experts who could understand computers were even less common.