Greetings, and thank you for your question. ICD-9 code 310.9 stands for "Unspecified nonpsychotic mental disorder following organic brain damage," which you already knew.
When a medical test, such as an MRI, is ordered, the ordering provider must place a reason and/or suspected diagnosis as the reason to order the test. This serves at least two purposes: to give the radiologist a problem to look for, to rule it out or rule it in as a problem, and secondly to provide a diagnosis code so insurance will pay for the procedure.
When we order MRI's, we do actually try to put something down that is useful, rather than pulling something out of thin air. In your son's case, the ordering provider actually gives a lot of info as to what he/she is thinking:
(1) Organic brain damage means there was injury to the brain, such as from trauma, like an accident, explosion (from an IED in Afghanistan, for instance), or assault; or from a stroke
; or from any other event that could cause physical damage to the brain.
(2) Nonpsychotic means that your son is not having psychoses as part of his clinical presentation - no hallucinations, no delusions, for example. This is important because psychoses often are located in specific parts of the brain, so the lack of them helps narrow down where the problem is NOT.
(3) Mental disorder and unspecified simply means your son's mental state has changed - depressed, anxious, moody, irritable, etc, but not in a way that makes us think specifically of a particular mental disorder, such as bipolar
(4) Following means that the injury to the brain led to the mental disorder.
Given this background, I hope this helps you in narrowing your search! Please let me know if I may be of further assistance, and please do not rate this until you are satisfied!