Electric-Field-Based Guidance for Percutaneous Catheter Vessel Crossing.

Percutaneous procedures to divert blood flow from one blood vessel to another can be performed with intravascular catheters but demand a method to align a crossing needle from one vessel to another. Fluoroscopic imaging alone is not adequate, and it is preferable to have a sensor on one catheter that detects the correct alignment of an incoming needle. This can be implemented by generating dipole electric fields from the crossing catheter which are detected by a receiving catheter in the target vessel and, thus, can calculate and display the degree of alignment, permitting the operator to rotate the crossing catheter to guarantee alignment when deploying a crossing needle. Catheters were built using this concept and evaluated in vitro. The results show that accurate alignment is achieved, and a successful crossing can be made. The concept is being further developed for further clinical evaluation.

Distal Re-Entry to Treat Lower Limb Chronic Total Occlusions Using a Novel Electrically Guided Re-Entry Catheter.

INTRODUCTION: Endovascular treatment of challenging infra-inguinal peripheral vascular disease is increasingly common because of new techniques and improved tools. The use of a novel electrically guided 5 F re-entry catheter is presented. By emitting a minute electrical field, detected by a target wire inserted from an opposing access, the catheter's orientation is accurately displayed to the operator, allowing precise re-entry without the need for fluoroscopic alignment. REPORT: An 84 year old man with tissue loss was treated for a long occlusion of the superficial femoral artery and tibial vessels. Successful subintimal recanalisation was achieved with the help of the ePATH re-entry catheter, restoring inline flow to the foot. CONCLUSION: This re-entry catheter benefits from an intuitive alignment method, smaller profile, and operator adjustable needle travel, making it a versatile tool for endovascular cases.

Murine heart volume: numerical comparison and calibration of conductance catheter models.

A full set of finite-element method (FEM) studies of the catheter within a cylindrical cuvette and within an elliptical cuvette are presented along with novel insight on the fundamental electromagnetic properties of the catheter. An in vitro experiment with modified small mouse pressure-volume catheters was conducted and the results are presented as a validation of the FEM models. In addition, sensitivity analysis on the electrode size and position is conducted and the results allow for a novel calibration factor based on catheter geometry to be presented. This calibration factor is used in conjunction with Wei's conductance volume equations to reduce the average measured error in cuvette volume measurements from 26.5% to 5%.

On the fundamental group of type II1 factors.

We present here a shorter version of the proof of our earlier work, showing that the von Neumann factor associated with the group Z(2)SL(2,Z) has trivial fundamental group.