I imagine a study would be warranted, if one does not already exist. If a statistically significant link could be established, why not run tests?
How much does it cost to have an MRI performed? How does it compare to the lifetime medical (and social) costs of an autism sufferer?
I'm just guessing here, but if even 1% of autism cases were caused by cysts or other treatable brain abnormalities, and hypothetical interventions had a 25% success rate, you'd end up spending $1.2M per case of autism cured (using the other poster's figure of $3K for an MRI scan). That seems well worth it to me. Certainly the cost delta between a functional member of society and someone that requires costly support their whole life is way more than $1.2M over a lifetime.
Of course this is like Drake's equation; taking an unknown and breaking it down into made-up numbers doesn't actually increase certainty, but fortunately, these numbers are a lot more knowable than the coefficients in Drake's equation. It's simply that I don't know them.
