Exercise-induced asthma is a condition of respiratory difficulty (bronchoconstriction) that is related to histamine release,is triggered by aerobic exercise, and lasts several minutes. Causes include medical conditions, environmental factors, and medications. The image below illustrates the pathogenesis of asthma.
A myelogram is an invasive diagnostic test that uses x-rays to examine the spinal canal. A special dye is injected into the spinal canal through a hollow needle. An x-ray fluoroscope then records the images formed by the dye. Myelograms can show conditions affecting the spinal cord and nerves within the spinal canal.
Myelography is an imaging examination that involves the introduction of a spinal needle into the spinal canal and the injection of contrast material in the space around the spinal cord and nerve roots (the subarachnoid space) using a real-time form of x-ray called fluoroscopy. Myelography is relatively safe and painless. 2  When a contrast material is injected into the subarachnoid space surrounding the nerve roots and spinal cord, it allows the radiologist to view outlines of the different areas of the spine that usually are not visible or distinguishable on x-rays.