What a bloody mesh

When a heart patient has an MRI scan,
they are injected with paramagnetic contrast agents to enhance the images. But
the contrast agents have to be excreted from the body before the next scan, and
this takes time. Now Marconi Medical Systems of Cleveland, Ohio, has a way to
speed things up (GB 2349825). The idea is to pass the patient’s blood through a
magnetised metal mesh. Weakly magnetised oxyhaemoglobin passes freely through
the mesh, but the strongly magnetised contrast agent sticks to it. The mesh is
continuously spooled through the flow to cleanse the blood quickly.