Thank you for writing in. Let me begin with antibodies
. These are molecules that the body produces to fight of infection and other foreign invasions. Normally there are several check mechanisms in the body to see to it that we do not produce antibodies to our own tissues. Despite this there are conditions where these control is overcome and antibodies to our own organs or tissues are produced. This results in several diseases. So the presence of Neuronal Voltage Gated Potassium Channel antibody could be due to one such phenomenon in your case.
One of the causes for such antibodies to develop are malignancies, especially of the lung or an organ called thymus
or sometimes lymphomas. PET scan was probably done in your case to see if such conditions are present. Apparently no such disease was identified and it is a good news.
Now in a PET scan we inject glucose
molecule and try to see any sites showing abnormal uptake of glucose. Cancer can cause increase in glucose uptake. But at the same time infections can as well do it. The SUV (uptake value) 3.4 indicates mildly increased glucose use and as mentioned in the report could be due to lymph nodes that are enlarged due to some infective process. This should not be a cause of worry in your case.
Hope I was able to clear your queries.