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.
1 Bipolar II involves less severe manic episodes than bipolar I; however, their depressive episodes are the same. 2  Cyclothymia is a chronic but milder form of bipolar disorder, characterized by episodes of hypomania and depression that last for at least two years.here is no single cause for bipolar disorder. Indeed, like all psychological disorders, bipolar disorder is a complex condition with multiple contributing factors, including: 1  Genetic: Bipolar disorder tends to run in families, so researchers believe there is a genetic predisposition for the disorder.