Spasm
1 - Contraction of smooth muscles in a vessel wall (or bowel, airways) reducing the vessel cross section and thereby reducing blood flow. The coronary arteries have a relatively high tendency to develop spasm. Vessel spasms may result from various local effects like damage to the vessel wall (PTCA) or injection of cold fluids. Severe spasms may cause ischaemia, and even myocardialinfarction. Vessel spasms may appear as filling defects in images, but should not be confused with filling defects due to other causes. 2 – Contraction of large muscle groups (arms, legs, jaws) as a result of brain injury. Such brain injury may be due to specific diseases (tumours, epilepsy) but can also be caused by infections and chemical stimuli. Particularly high osmolar ionic contrast media can cause severe spasms or convulsions if injected directly in to the subarachnoid space or if passing through a damaged blood-brain barrier. Non-ionic contrast media normally do not cause spasms.
GE Healthcare Glossary