Is it possible to diagnose ADHD on a baby with modern scanning technology?

I wish! Adhd is a neurodevelopmental disorder that is highly inheritable & often co-exists with other disorders. Prenatal factors that increase the risk of having adhd are those that cause structural or functional abnormalites in the developing brain, like prenatal exposures to alcohol, tobacco & drugs, infections, maternal illnesses, genetic syndromes, drops in oxygen/blood flow, & prematurity.
No. Adhd is not a disease like a missing kidney; more like a personality trait, or a skill set. Scanning won't help you there, much.
NO . There is a lot of conflicting reasearch on the variety of areas of the brain effected (predominantly frontal subcortical) even with fancy computer models of many children. This really likely precludes any reliable scanning diagnostics for possible future development of adhd in infants. There are some proponents of scanning older adhd - but check out pet scans and adhd on quackwatch.Com 1st.
No. No, no scans, eegs, labs....Adhd is not a disease.There are several rating scales symptoms checklists, pychological tests and continue performance test that add imformation or help recognize or rule out co-existing conditions, but no they do not diagnose adhd.Only a trained experienced professional with the iad of a thorough examination, physical exam and direct observation of childs behavior couldhelp.