Combination catheter for invasive probe delivery and balloon dilation

A method for sequentially dilating and then imaging a region of a subject:

• using an ultrasound probe, a guidewire, and a catheter, wherein the catheter comprises an elongate, flexible member having a lumen in its distal length;
• a dilation balloon attached to a proximal portion of the distal length, the outside of the distal length and balloon being sized for passage into the region of the subject and the lumen having a diameter sized to accept either the guidewire or the ultrasound probe, wherein the lumen splits into a dual lumen proximal of said balloon, the dual lumen comprising a guidewire lumen sized to accept the guidewire and a probe lumen sized to accept the ultrasound probe, the flexible member further comprising a third lumen wherein the third lumen communicates with the balloon, the method comprising the steps of:
• advancing the guidewire through the subject until a distal tip of the guidewire is distal of the region of the subject to be imaged;
• advancing the catheter through the distal lumen and the guidewire lumen, until the balloon has passed into the region to be dilated;
• inflating and then deflating the balloon by flowing a fluid through the third lumen;
• pulling the guidewire proximally, and leaving the distal tip of the guidewire within the wire lumen;
• advancing the ultrasound probe tip into the distal lumen portion of the catheter;
• preventing the ultrasound probe from extending distally beyond the catheter;
• and
• activating the probe to obtain post-dilation ultrasound images of the region.

A catheter for ultrasound imaging and balloon dilation within a region of a patient, comprising:

• a flexible distal tip portion with a tip lumen having a diameter greater than a guidewire diameter and less than a probe diameter;
• a flexible imaging window section having a lumen connected to the tip lumen, and having a diameter larger than said guidewire or said ultrasound probe, and being connected to a proximal end of the lumen;
• a flexible balloon dilation section comprising:
• a balloon with an inflate/deflate tube;
• and a through tube, wherein a through tube lumen in said through tube alternately accepts the guidewire or the probe;
• the through tube lumen connected proximally with the lumen in the imaging window section;
• a flexible lumen portion comprising:
• an ultrasound probe lumen, a guidewire lumen, and an inflation/deflation lumen;
• and
• a flexible transition region between the flexible lumen portion and the balloon dilation section, wherein the probe lumen and the wire lumen join into a single lumen that connects proximally to the through tube.

A method of imaging and dilating a region of a lumen in a subject comprising the steps of:

• positioning a guidewire so that the distal tip of the guidewire is within the lumen and distal of a region of the lumen to be imaged and dilated;
• advancing a catheter using the guidewire as a guidance device until a distal end of the catheter is within the lumen, and distal of the region of the lumen to be imaged and dilated;
• retracting the guidewire until it becomes proximal of the region of the lumen to be imaged and dilated;
• advancing an ultrasound probe within the catheter until the tip is within the region of the lumen to be imaged and dilated;
• preventing the ultrasound probe from extending distally beyond the catheter;
• activating the probe to obtain images;
• advancing the catheter using a method comprising the steps of:
• retracting the probe, advancing the guidewire, and moving the catheter distally using the guidewire as a guidance device until a baloon dilation portion of the catheter is within the region to be imaged and dilated;
• and
• dilating the region of the lumen in the subject by temporarily inflating the balloon through a catheter lumen.

A method for backloading a catheter comprising:

• a transition region for back loading a guidewire through a single lumen and into a selected lumen of a multiple lumen section where the single lumen divides into two or more lumens, the transition region containing a cavity connected to one or more of the lumens, the shape of the cavity in a cross-section perpendicular to a longitudinal axis of the catheter taken at a point where the lumens connect, being defined by:
• a first arc and a second arc connected by two substantially straight side walls,
• wherein the cavity cross-section gradually blends into the single-lumen cross-section over a longitudinal distance of at least about two lumen diameters;
• the method comprising the steps of:
• inserting the proximal end of the guidewire into the single lumen;
• bending the catheter so that a selected lumen of the two or more lumens is on the outer surface away from the center of curvature;
• and
• moving the guidewire longitudinally into the selected lumen.