Detection of fluidic current generated by rotating magnetic particles

A method of treating a fluid obstruction in a blood vessel of a subject having at least partially occluded blood flow, the method comprising:

• introducing magnetic particles into the blood vessel of the subject having at least partially occluded blood flow;
• infusing a chemical adjunct into the subject;
• rotating a permanent magnet at a position outside a body of the subject at a rotation frequency,
• wherein the rotation of the permanent magnet generates a rotating magnetic field and a magnetic gradient sufficient to cause the magnetic particles to agglomerate into rotating stir rods that rotate at the rotation frequency within the blood vessel and travel to a location of the fluid obstruction in the blood vessel,
• wherein the rotating stir rods create a fluidic current within the blood vessel that causes the chemical adjunct to travel toward the fluid obstruction even though blood flow is occluded;
• and
• detecting the fluidic current created by the rotating stir rods using an ultrasound-based diagnostic imaging system, thereby tracking the infusion of the chemical adjunct in real time toward the fluid obstruction.