For what it's worth, it's ~$160 in Japan. ( http://www.npr.org/templates/story/story.php?storyId=1205455... ) Interesting seeing this here on HN after my wife and I just finished watching "Frontline: Sick in America" on Netflix tonight, in which an American reporter travels to 5 countries that provide some form of universal healthcare to discuss (with doctors, administrators, and patients) the different mechanics, wh…
MRI specifically is overused and kind of crappy in Japan. In the rest of the world, the standard is for a 1-3T MR study; in Japan, you get a lot of 0.5 and even lower (0.2T! wtf) MR studies. They're used for a lot of health screenings, whereas in the rest of the world they're more often used for actual problems.
MRIs aren't something that can really be overused. Unlike CT scans, or pretty much any non-MRI method of imaging the inside of the body, they don't harm the patient.
Even though you are right that many of the MRI machines in Japan are lower-resolution cheaper models, that is largely because there are way more MRI machines here, and they are used for routine diagnostics, to find actual problems. Your local single-doctor clinic in the boonies often has mRI equipment here.
I have a personal interest in this topic, as I have MS. Lucky for me, I am doing fine, but in Japan I get a brain MRI every 6 months just to keep an eye on how it is going. When I was back in the states 3 years ago I had a typical employer-based HMO. I went to the doctor and told him here's my deal, I have MS, my doctor in Japan said I should have another MRI in October to see what's up with it.
The doctor flatly refused -- MRIs were only available after physical symptoms had developed. Of course, at that point, the available treatments for a flare-up of MS are less effective at preventing long-term neurological problems. (Happily, I am back in Japan now.)
My point is that MRIs are a wonderful tool, and as you and other commenters have pointed out, they are much more widely used here than in the US. Something wonky with your knee? OK, let's get an MRI and check it out. I don't see anything wrong with that.
And in cases where there is a problem, there is no difficulty at all here in getting a referral to a specialist at a hospital with the latest cutting-edge MRI gear if necessary.
Using MRI technology for health screening and preventative/proactive treatment is great.