Science Daily just posted an article reporting on how a group have apparently developed a brain imaging technique to diagnose Autism in adults. This, however, is not really what the article published in "The Journal of Neuroscience" is saying.
I'm really annoyed at the implications that Science Daily is making. To me, their article has a flavor of "Now everyone can get tested!" To me, if you have sensory difficulties, social challenges or other features of Autism-Aspergers that are at a level to be distressing to you, then of course you should seek help. But since there's no real medical cure for ASD (besides one being developed for people with fragile X. And yes I know it's also from science daily, but there have been a few stories about it over the last year or so). So being diagnosed as an adult probably won't do tons for you, other than the relief some people find in having a label for a condition.
Personally I find the real message of the article to be much more interesting. Essentially the researchers found fairly strong evidence that a range of abnormalities in 5 different brain regions seem to be found consistently in people with Autism (sample size was only 20 though, and the control population were people with ADHD) may contribute to autism as a whole. This lends weight to pre-existing ideas that the range in variations in physical neurological abnormalities leads to the cluster of spectrum features that "make up" autism. If anything it helps further research into how these regions working in concert can be distruptive to neuro-typical functioning.
...Just remember, the brain is extremely elastic. People with hydrocephally and people who do not have this condition can have totally different looking brain scans, but have relatively the same functioning and IQ level, it all depends on if/how the brain adapts.