An Imaging technique that uses a large donut-shaped magnet and radio waves to look at the organs of the body. A doctor may order a this procedure, also called an MRI, to find a blood clot blood clot: A mass of blood that forms when platelets stick together. Harmful blood clots are more likely to happen in PNH. The term thrombus describes a blood clot that develops and attaches to a blood vessel. The term embolus describes a blood clot or other foreign matter that gets into the bloodstream and… . MRI does not use radiation.
