Scan Medical Insurance

Why don't doctors just give everyone a heart scan or full body scan?

I understand they are expensive, but if they became routine, like you had one every or every other year, the machines would be paid for extremely quickly. If everyone had one, we could catch things such as heart disease and cancer in their treatable early stages thus saving even more money. So why isn't this a routine practice? I understand that it could be laborious to read the scans, but it could be done. Especially with heart scans. It is a ten minute test with less than eight images taken. Women get yearly mammograms, why can't this be added in as a yearly preventative test over a certain age? Andrew, currently without insurance coverage at all a heart scan is only $500. If they became routine, had co-pays and the like, the machine would be paid for extremely quickly. It would then just be a routine cost, no more than a mammogram. Ok, I see that a full body scan is unrealistic, but a heart scan, to me, is no different than a colonoscopy or mammograms

Public Comments

1. Firstly there are so many scans and images that are to be analysed in case of full body scan, and a doctor can check if only he assumes that the person has some problem in some part of his/her body. So, its very difficult to analyses full body scan if you do not have any symptoms. There are many tests which are done routinely by which most of the diseases can be detected. And also exposure to these scans is not good for the body
2. There are so many tests that are so specific, even if you know what area of the body you are looking for. If you have a family history of heart disease, then getting a full blown heart checkup every year after 35 might not be a horrid idea. But we pay enough for health insurance as it is now. If everyone got tested for everything every year, the average health insurance premium would be at least 10 times what it is now. Being safe isn't a bad idea, but the huge majority of people go through life a problem that can only be caught by vigilant body scans. Its a noble thought, and as technology improves, this may be possible, but for now we must stick to our standard annual physicals and a healthy lifestyle.
3. You misunderstand tests. Any medical test has four possible outcomes: (1) the person has the disease and has a positive test result (2) the person has the disease and has a negative test result (3) the person does not have the disease but has a positive test result or (4) the person does not have the disease and has a negative test result. There would be some lives saved by scenario 1, at huge costs, and those with scenario 4 would be somewhat reassured. But those with scenario 2 would be falsely reassured by a "false negative" test result. The real problem, though, is in scenario 3 with the false positive test result. What you'd wind up with is large numbers of people overwhelming the system with follow-up tests, more expense, and not inconsequential risks (people do die from cardiac catheterizations, for instance), not to mention the mental distress of telling healthy people they have a test positive for heart disease, or worse. One of the first things you learn in medical school is Bayes' theorem. If you don't understand Bayes', you can't begin to think about whom to test for what. Then you must look at the individual test you're considering and study its sensitivity and specificity (measures of the rates of false negatives and false positives). Only then is it possible to decide how widely to use the test. The idea is not simply one of deciding how much good you can do, even if you have unlimited funds (dreamy but unrealistic); one must also consider the amount of harm done by the testing.
4. All screening tests have certain requirements in order for them to be used routinely like mammograms. A problem that one runs into with, say, full body CT scans is that it's quite expensive compared to mammography. There will be an awful lot of false positive lesions or lesions that look bad that require a workup which turn up to be benign. This means a lot more testing, money, perhaps invasive work and anxiety on the part of the patient. One also has to select a population where a given disease is prevalent, so that's why the issue of whether low dose thoracic CT should be done for smokers to screen for lung cancer. In non-smokers, you simply don't have the same prevalence to warrant this sort of screening as the positive predictive value begins to decline. The same goes for 2D echocardiography of the heart. In Italy, they had enough prevalence of certain cardiac structural anomalies that for a number of years they did 2D echocardiography (heart scans) on young patients, but I'm not sure if this is still involved. In short, besides the costs associated with a test, there are a number of other criteria that a test must meet in order to make it a reasonable screening test like mammography. A lot of it has to do with the statistical requirements of a given test to do what it's supposed to.
5. Great answer by John de Witt.