Any abnormal reaction of a patient to an examination or procedure, like for example claustrophobia or side effects of MRIcontrast agents.
A claustrophobic attack is MRI scanner dependent and more rare with an open MRI. An adverse reaction with magnetic resonance imagingcontrast medium is very infrequent. In general, adverse reactions increase with the quantity of contrast media (usual dose of paramagnetic contrast agents is 0.1 mmol/kg) and also with the osmolarity of the compound.
Most frequently encountered adverse reactions are heat sensation, dizziness, nausea, hypotension due to vasodilatation, which can progress to hypotensive shock and anaphylactic reactions.
See also MRI Safety, Contrast Enhanced MRI, Breast MRI, and Cardiac MR imaging.
California-based research and development company. Alliance has several patents regarding 'microbubble' compositions such as Imagent® that are intended to enhance ultrasound imaging and Imagent GI as a gastrointestinal MRIcontrast agent. Another product is Oxygent™, a synthetic 'blood substitute'.
Automatic bolus detection is used to trigger the begin of the MRI scan with the time the contrast agent reaches the region of interest. The acquisition process is started once the signal is increased in this region.
There are similar methods used by the scanner manufacturer (see MRI Acronyms for Automatic Bolus Detection). After injection of the contrast agent the region of interest is monitored (e.g. with a spin echo or gradient echo sequence). When the signal increases the scan is automatically triggered or the operator is informed.