A lung scan is a type of nuclear scanning test. It is most often used to find a pulmonary embolism. This is a blood clot that prevents normal blood flow in the lung. Two types of lung scans are usually done together: Ventilation scan. During this scan, you inhale a radioactive tracer gas or mist. Pictures from this scan can show areas of the lungs that aren't getting enough air or that hold too much air.
One interesting theory on the cause of manic depression or bipolar disorder is that there is a super-fast biological clock located in the hypothalamus, in the center of the brain, which is actually a tiny cluster of nerves called the supra chiasmatic nucleus or SCN.
Bipolar I disorder is referred to as manic depression. Manic depression presents differently for each individual, but the diagnosis requires a history of at least one manic episode. A manic episode involves a period of time in which emotions are elevated in a positive direction, often for no particular reason. Brief elation at a piece of good news is not manic, but a few weeks of that feeling could indicate mania. Individuals with bipolar I often spiral into depression following episodes of mania.