Systems and methods for an orthogonal frequency division multiplexing multipoint-to-point communications system are provided. The pressure sensor is equipped with a pressure sensing diaphragm assembly which includes a first diaphragm, a second diaphragm, and liquid or gel. A flow resistor in the catheter provides for infusion andor aspiration to be concentrated primarily at a clot treatment area in a blood vessel while also providing optional infusion andor aspiration distal to the treatment area. Further, the presence of the self-assembled monolayer on the gate insulating film tends to reduce hysteresis.