Abstract:
An IVUS pigtail catheter is provided. The IVUS pigtail catheter includes an array of transducers for performing intravascular ultrasound imaging and a pigtail end portion for performing angiographic imaging. The IVUS pigtail catheter facilitates both IVUS imaging and angiographic imaging without the need to exchange catheters. This allows surgical procedures performed using the IVUS pigtail catheter to be faster, more accurate, and less complicated. Methods of utilizing the IVUS pigtail catheter are also provided.

Description:
CROSS REFERENCE 
     This application claims priority to and the benefit of, U.S. Provisional Patent Application Ser. No. 61/392,814, filed on Oct. 13, 2010, the entirety of which is incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present disclosure relate generally to the field of medical devices and, more particularly, to catheters sized for use within vasculature and associated methods of use. 
     BACKGROUND 
     In the United States and many other countries, heart disease is a leading cause of death and disability. One particular kind of heart disease is atherosclerosis, which involves the degeneration of the walls and lumen of the arteries throughout the body. Scientific studies have demonstrated the thickening of an arterial wall and eventual encroachment of the tissue into the lumen as fatty material builds upon the vessel walls. The fatty material is known as “plaque.” As the plaque builds up and the lumen narrows, blood flow is restricted. If the artery narrows too much, or if a blood clot forms at an injured plaque site (lesion), flow is severely reduced, or cut off and consequently the muscle that it supports may be injured or die due to a lack of oxygen. Atherosclerosis can occur throughout the human body, but it is most life threatening when it involves the coronary arteries which supply oxygen to the heart. If blood flow to the heart is significantly reduced or cut off, a myocardial infarction or “heart attack” often occurs. If not treated in sufficient time, a heart attack often leads to death. Further, the weakening of vessel walls can lead to an aneurysm or swelling of the vessel that, if left untreated, will rupture and lead to internal bleeding and often death. Aneurysms commonly occur in the aorta. 
     The medical profession relies upon a wide variety of tools to treat heart conditions and major vessel diseases, ranging from drugs to minimally invasive procedures to open heart “bypass” surgery. Often, a lesion can be diagnosed and treated with minimal intervention through the use of catheter-based tools that are threaded into the coronary arteries via the femoral artery in the groin. For example, one treatment for lesions is a procedure known as percutaneous transluminal coronary angioplasty (PTCA) whereby a catheter with an expandable balloon at its tip is threaded into the lesion and inflated. The underlying lesion is re-shaped, and hopefully, the lumen diameter is increased to improve blood flow. In the case of aortic aneurysms, an endovascular aortic repair (EVAR) or thoracic endovascular aortic repair (TEVAR) may be utilized to introduce a stent graft into the vasculature. Such techniques have traditionally relied on CT scans performed before surgery and angiograms during surgery to identify important anatomical features of the vasculature associated with the interventions. However, the information from a CT scan is often inaccurate at the time of surgery since the aneurysm or other condition is continually evolving over time. 
     In recent years, a technique has been developed for obtaining detailed information about coronary and peripheral vessels. The technique, known as Intravascular Ultrasound (IVUS), employs one or more very small transducers arranged towards the end of a catheter to provide electronically transduced echo signals to an external imaging system in order to produce a two or three-dimensional image of the lumen, the vessel tissue, and/or the tissue surrounding the vessel. These high quality images are generated in substantially real time. The IVUS images allow a user to view the form and structure of a site within a vessel rather then merely determining that blood is flowing through a vessel. 
     While the existing devices and methods have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects. The imaging catheters, systems, and associated methods of the present disclosure overcome one or more of the shortcomings of the prior art. 
     SUMMARY 
     In one embodiment, an IVUS pigtail catheter is provided. The IVUS pigtail catheter includes one or more transducers for performing intravascular ultrasound imaging and a pigtail end portion for performing angiographic imaging. The IVUS pigtail catheter facilitates both IVUS imaging and angiographic imaging without the need to exchange catheters. This allows surgical procedures performed using the IVUS pigtail catheter to be faster, more accurate, and less complicated. 
     In another embodiment, a method of imaging a vessel is provided. In some instances, the method comprises introducing a catheter into the vessel, where the catheter includes an array of transducers configured for intravascular ultrasound (IVUS) imaging and a pigtail end portion configured for introducing a contrast medium into the vessel for angiographic imaging. The transducer array is utilized to obtain one or more IVUS images of the vessel. A contrast medium is introduced into the vessel through the pigtail end portion of the catheter and utilized to obtain one or more angiographic images of the vessel. In some instances the steps of utilizing the array of transducers of the catheter to obtain one or more IVUS images of the vessel and utilizing the contrast medium within the vessel to obtain one or more angiographic images of the vessel are performed simultaneously or in tandem to co-register these modalities in real time. Since the catheter is capable of facilitating both IVUS imaging and angiographic imaging, there is no need to remove the catheter from the vessel for the different modalities. 
     In some instances, introducing the catheter into the vessel includes guiding the pigtail end portion of the catheter to a portion of the vessel with the pigtail end portion in an elongated orientation and transitioning the pigtail end portion to a curved orientation adjacent the portion of the vessel. In that regard, the catheter may be introduced over a guide wire such that the pigtail end portion is transitioned to the curved orientation by removing the guide wire from at least the pigtail end portion of the catheter. The contrast medium is injected through a lumen extending along a length of the catheter to the pigtail end portion in some instances. 
     In some embodiments, the method of imaging the vessel is utilized in the context of a surgical procedure. For example, an endoluminal device, such as a stent or graft, may be deployed at a particular location within the vessel based on the IVUS and/or angiographic images. The particular location within the vessel is selected based on one or more characteristics of the vessel tissue determined from the IVUS and/or angiographic images. Further, the IVUS and/or angiographic images may be utilized to confirm proper placement of the stent within the vessel after deployment of the endoluminal device. In some instances, deploying the endoluminal device is part of an endovascular aortic repair (EVAR) such that confirming proper placement of the endoluminal device within the vessel includes confirming the patency of the renal arteries after the endoluminal device deployment. In some instances, the method of imaging the vessel is utilized as part of a diagnostic procedure. 
     In another embodiment, a catheter is provided. The catheter includes an elongated flexible body having a lumen extending along its length from a proximal portion to a distal portion. An array of transducers configured for intravascular imaging is positioned adjacent the distal portion. A pigtail portion is also positioned adjacent the distal portion. The pigtail portion is in fluid communication with the lumen of the elongated flexible body such that the pigtail portion is configured for introducing a contrast medium for angiographic imaging into the vessel from the lumen. In some instances, the pigtail portion defines a distal tip of the catheter. The pigtail portion may include a plurality of openings extending radially outward from a central lumen for introducing the contrast medium into the vessel. In that regard, the lumen of the elongated flexible body and the central lumen of the pigtail portion are sized and shaped to receive a guidewire in some instances. In some embodiments, the pigtail portion is transitionable between an elongated orientation and a curved orientation by removing the guidewire from the lumen of the pigtail portion. The transducers are positioned circumferentially around the lumen of the elongated flexible body in some instances. 
     In a further embodiment, a method is provided. The method includes introducing a catheter into a vessel over a guidewire, introducing a contrast medium into the vessel through a plurality of openings in a pigtail portion of the catheter, and utilizing the contrast medium introduced through the plurality of openings in the pigtail portion of the catheter to perform angiographic imaging of a portion of the vessel. The method also includes utilizing a transducer array of the catheter positioned adjacent to the pigtail portion of the catheter to perform intravascular ultrasound imaging of the portion of the vessel. In that regard, the step of utilizing the contrast medium to perform the angiographic imaging and the step of the utilizing the transducer array to perform intravascular ultrasound imaging are performed simultaneously in some instances. The guidewire is retracted from a lumen of the catheter to cause the pigtail portion of the catheter to transition from an elongated insertion configuration to a curved imaging configuration in some instances. The step of introducing the contrast medium into the vessel through the pigtail portion of the catheter may be performed with the pigtail portion of the catheter in the curved imaging configuration in such instances. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a catheter system according to one embodiment of the present disclosure. 
         FIG. 2  is a side view of a distal portion of the catheter system of  FIG. 1 . 
         FIGS. 3-6  generally illustrate an exemplary method utilizing the catheter system of  FIGS. 1 and 2  according to one aspect of the present disclosure. 
       More specifically,  FIG. 3  is a partial cutaway view of vasculature illustrating use of the catheter system of  FIGS. 1 and 2  according to one aspect of the present disclosure. 
         FIG. 4  is a partial cutaway view of vasculature similar to that of  FIG. 3 , but illustrating use of the catheter system of  FIGS. 1 and 2  according to another aspect of the present disclosure. 
         FIG. 5  is a partial cutaway view of vasculature similar to that of  FIGS. 3 and 4 , but illustrating use of the catheter system of  FIGS. 1 and 2  according to another aspect of the present disclosure. 
         FIG. 6  is a partial cutaway view of vasculature similar to that of  FIGS. 3-5 , but illustrating use of the catheter system of  FIGS. 1 and 2  according to another aspect of the present disclosure. 
         FIG. 7  is a partial cross-sectional view of a catheter system in a first orientation according to another embodiment of the present disclosure. 
         FIG. 8  is a partial cross-sectional view of the catheter system of  FIG. 7  in a second orientation. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is intended. Any alterations and further modifications in the described devices, instruments, methods, and any further application of the principles of the disclosure as described herein are contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the features, components, and/or steps described with respect to one embodiment may be combined with the features, components, and/or steps described with respect to other embodiments of the present disclosure. 
     Referring to  FIGS. 1 and 2 , shown therein is a catheter system  100  according to one embodiment of the present disclosure. In particular,  FIG. 1  is a perspective view of the catheter system  100 , while  FIG. 2  is side view of a distal portion of the catheter system. As shown, the catheter system  100  includes an elongated tubular member  102 . The elongated tubular member includes a proximal portion  104  and a distal portion  106 . Adjacent the proximal portion  104  is a y-connector  108 . The y-connector  108  includes arms  110  and  112 . In the illustrated embodiment, the arm  112  generally extends along the longitudinal axis of the elongated tubular member  102 , while the arm  110  extends at an oblique angle relative to the longitudinal axis of the elongated tubular member. The arm  112  is configured to interface with a power injector or other mechanism for introducing a contrast medium through a central lumen of the elongated tubular member  102  to the distal portion  106 , as will be discussed in greater detail below. The arm  110  interfaces with elongate member  114  that leads to interface  116 . The interface  116  is configured to connect the catheter system  100  to a patient interface module. More specifically, in some instances the interface  116  is configured to communicatively connect at least an IVUS portion  118  of the catheter system  100  to a patient interface module suitable for carrying out IVUS imaging. In some instances, the interface  116  includes components or features similar or identical to those disclosed in U.S. Pat. No. 7,641,480, which is hereby incorporated by reference in its entirety. 
     The IVUS portion  118  is positioned adjacent to the distal portion  106  of the elongated flexible member  102 . The IVUS portion  118  includes the components associated with an IVUS module, such as transducer(s), multiplexer(s), electrical connection(s), etc., for performing IVUS imaging. It is understood that, in some instances, wires associated with the IVUS portion  118  extend along the length of the elongated tubular member  102  through the arm  110  and along elongated member  114  to the interface  116  such that signals from the IVUS portion  118  can be communicated to the patient interface module that the interface  116  is connected to. In some instances, the IVUS portion  118  communicates wirelessly with the patient interface module. 
     The IVUS portion  118  may utilize any IVUS configuration that allows the elongated tubular member  102  to be introduced over a guidewire. For example, in some instances, the IVUS portion  118  utilizes an array of transducers (e.g., 32, 64, 128, or other number transducers) disposed circumferentially about a central lumen of the elongated tubular member  102  in a fixed orientation. In other embodiments, the IVUS portion  118  is a rotational IVUS system. In some instances, the IVUS portion  118  includes components similar or identical to those found in IVUS products from Volcano Corporation, such as the Eagle Eye® Gold Catheter, the Visions® PV8.2F Catheter, the Visions® PV 018 Catheter, and/or the Revolution® 45 MHz Catheter, and/or IVUS products available from other manufacturers. Further, in some instances the catheter system  100  includes components or features similar or identical to those disclosed in U.S. Pat. Nos. 4,917,097, 5,368,037, 5,453,575, 5,603,327, 5,779,644, 5,857,974, 5,876,344, 5,921,931, 5,938,615, 6,049,958, 6,080,109, 6,123,673, 6,165,128, 6,283,920, 6,309,339; 6,033,357, 6,457,365, 6,712,767, 6,725,081, 6,767,327, 6,776,763, 6,779,257, 6,780,157, 6,899,682, 6,962,567, 6,976,965, 7,097,620, 7,226,417, 7,641,480, 7,676,910, 7,711,413, and 7,736,317, each of which is hereby incorporated by reference in its entirety. 
     The catheter system  100  further includes a pigtail portion  120  positioned adjacent to and distal of the IVUS portion  118 . In the illustrated embodiment, a transition  122  connects the IVUS portion  118  to the pigtail portion  120 . In that regard, the pigtail portion  120  is a fixedly connected to the IVUS portion  118  and the elongated tubular member  102 . In some instances, the pigtail portion  120  and the elongated tubular member  102  are formed together as a single integral piece. In other instances, the pigtail portion  120  is formed as a separate component and then fixedly secured to the IVUS portion  118  and/or the elongated tubular member  102 . In that regard, the pigtail portion  120  is fixedly secured to the IVUS portion  118  and/or the elongated tubular member  102  using one or more of an adhesive, a threaded engagement, a snap-fit engagement, a frictional engagement, over-molding, heat-shrinking, heat welding, and/or any other mechanism for fixedly connecting the pigtail portion  120  to the IVUS portion  118  and/or the elongated tubular member  102 . 
     The pigtail portion  120  includes a proximal portion  124 , a distal tip  126 , and an intermediate portion  128 . Generally, the pigtail portion  120  is transitionable between an elongated configuration (See, e.g.,  FIGS. 3 and 5 ) where the intermediate portion  128  extends substantially along the longitudinal axis of the elongated member  102  and a curved configuration (as shown in  FIGS. 1 and 2 ) where the intermediate portion  128  curves or bends relative to the longitudinal axis of the elongated member. In that regard, the curved configuration illustrated in  FIGS. 1 and 2  is for exemplary purposes only and in no way limits the manner in which the intermediate portion  128  may curve in other embodiments. Generally, the intermediate portion  128  may be configured to take on any desired arcuate profile when in the curved configuration. In some instances, the pigtail portion  120  (or at least the intermediate portion  128 ) is biased towards the curved configuration such that the pigtail portion resiliently returns to the curved configuration when a force utilized to hold the pigtail portion in the elongated configuration is removed. For example, as described below with respect to  FIGS. 3-6 , the pigtail portion  120  may be introduced and/or removed from a vessel over a guidewire that will maintain the pigtail portion in the elongated configuration. Retracting or removing the guidewire from the pigtail portion  120  allows the pigtail portion  120  to transition to the curved configuration. 
     Transitioning the pigtail portion  120  to the curved configuration helps to facilitate the introduction of contrast medium into the vessel without causing damage to the vessel. In that regard, because of the flow of fluid (e.g., blood) through the vessel it is often necessary to introduce the contrast medium into the vessel using a power injector to ensure that enough contrast medium is introduced into in the vessel to obtain a useful angiographic image of the vessel. However, using such high pressure injection with the pigtail portion  120  in the elongated configuration could result in damage to the vessel walls (e.g., puncture). The curved configuration of the pigtail portion  120  in combination with the plurality of openings  130  extending radially outward from a central lumen of the pigtail  120  portion allows the introduction of sufficient contrast medium to capture an angiographic image of the vessel without causing damage to the vessel. In some instances, the contrast media is introduced using a syringe, such as a 10 cc or 20 cc syringe. 
     In the illustrated embodiment, the contrast medium is injected through the arm  112  of the y-connector  112 , along the length of the elongated tubular member  102  and into the pigtail portion  120 . In that regard, the contrast medium is introduced through a common or shared central lumen that extends along the entire length of the device (i.e., through the elongated tubular member  102 , the IVUS portion  118 , and the pigtail portion  120 ), in some instances. In addition to allowing the introduction of the contrast material, the central lumen is sized and shaped to facilitate introduction of the pigtail portion  120 , IVUS portion  118 , and elongated tubular body  102  over a guidewire. In some instances, the central lumen has a substantially constant diameter along its length. In other instances, the diameter of the central lumen varies along the length of the device. For example, in some instances, the central lumen may have a different diameter within one or more of the elongated tubular body  102 , the IVUS portion  118 , and the pigtail portion  120  as compared to the diameter within another of the elongated tubular body  102 , the IVUS portion  118 , and the pigtail portion  120 . The diameter of the central lumen is generally between 0.01 inches and 0.05 inches and, in some instances, is between about 0.14 inches and about 0.038 inches. However, the diameter of the central lumen may be larger or smaller than these exemplary ranges in other embodiments. In one particular embodiment, the diameter of the central lumen is sized to receive a guidewire having an outer diameter between 0.035 inches and 0.038 inches. 
     Similarly, in some instances, the outer diameter of the catheter is substantially constant along its length such that the elongated tubular member  102 , the IVUS portion  118 , and the pigtail portion  120  have substantially the same outer diameters. In other instances, the outer diameter of the catheter varies along the length of the device (as shown in the embodiment of  FIGS. 1 and 2 ). For example, in some instances, the outer diameter is different adjacent one or more of the elongated tubular body  102 , the IVUS portion  118 , and the pigtail portion  120  as compared to the outer diameter adjacent another of the elongated tubular body  102 , the IVUS portion  118 , and the pigtail portion  120 . For example, as best seen in  FIG. 2 , the outer diameter of the IVUS portion  118  is larger than the outer diameter of the pigtail portion  120  such that the transition portion  122  tapers from the IVUS portion  118  down to the pigtail portion  120 . Where the outer diameter changes in size there is typically a smooth transition (as illustrated by the taper of transition portion  122 ) to avoid any sharp or abrupt edges that could catch or cause damage to a vessel as the catheter is being introduced into the vessel. The maximum outer diameter of the catheter is generally between 0.03 inches and 0.15 inches and, in some instances, is between about 0.10 inches and about 0.12 inches. However, the maximum outer diameter of the catheter may be larger or smaller than these exemplary ranges in other embodiments. In the illustrated embodiment of  FIGS. 1 and 2 , the pigtail portion  120  has an outer diameter of 4 F or approximately 0.053 inches, while the IVUS portion  118  has an outer diameter of 8.2 F or approximately 0.107 inches. 
     In some embodiments, one or more of the pigtail portion  120 , the IVUS portion  118 , and the elongated tubular member  102  include fiducial markers such that the relative location of the catheter components within the vessel can be determined from a resulting image. In that regard, each of the portions (i.e., pigtail portion  120 , IVUS portion  118 , and elongated tubular member  102 ) may include one or more visualization markers that are formed from a different material or are otherwise distinguishable from the majority of that portion of the catheter in the resulting images. In some instances, the markers are particularly suited for identification in angiographic images. 
     Referring now to  FIGS. 3-6 , shown therein are aspects of a method of utilizing the catheter system  100  according to one embodiment of the present disclosure. In particular, use of the catheter system  100  will be described in the context of an endovascular aortic repair (EVAR) procedure. As an initial matter, it should be understood that the particular method described is for exemplary purposes only and in no way limits the types of procedures, including both diagnostic and surgical, that the catheter systems of the present disclosure may be used to perform. Rather, the exemplary method described below illustrates the concepts and features provided by the present disclosure that may be carried into use in a wide array of procedures, especially those where it would be advantageous to have both IVUS and angiographic images of an anatomical structure. For example, it is specifically contemplated that the catheter systems of the present disclosure will be used in a wide variety of minimally invasive heart treatments, including but not limited to valve repair, valve replacement, endovascular graft placements, endovascular graft revisions, stent placements, aneurysm repairs, coronary artery bypass surgery, transmyocardial laser revascularization, repair of atrial septal defects, repair of ventrical septal defects, and/or other minimally invasive vessel treatments in the heart chambers, aorta, inferior vena cava, superior vena cava, arteries, veins, and/or other vessels. Further, it is specifically contemplated that the catheter system of the present disclosure will be used in a wide variety of minimally invasive diagnostic and/or surgical procedures in vessels throughout the human body (e.g., torso, arms, legs, head, or otherwise) or in vessels of other animals. Further, in some instances the catheter systems are sized and shaped for use in pediatric applications. 
     Referring first to  FIG. 3 , the pigtail portion  120 , the IVUS portion  118 , and at least the distal portion of the elongated tubular member  102  are shown positioned within an aorta  150 . As shown, the aorta  150  is connected to a right iliac  152 , a left iliac  154 , a right renal artery  156 , and a left renal artery  158 . The aorta  150  generally defines a central lumen  160  extending therethrough. As shown, plaque  162 ,  164  has built up along the walls of the aorta  150 . This condition, often referred to as atherosclerosis, can result in the excessive enlargement of the aorta  150  (as shown by the bulging profile of the aorta in  FIG. 3 ) resulting from the aorta&#39;s effort to compensate for the plaque buildup. Atherosclerosis often leads to an aneurysm. In other instances, the walls of the aorta  150  are weakened due to a breakdown in the material forming the walls. Accordingly, the blood pressure within the aorta  150  causes the weakened walls of the aorta to expand outwardly creating an aneurysm. In still other instances, the plaque buildup narrows the central lumen, resulting in a stenosis that limits the amount of blood flow through the vessel. A stenosis that limits the amount of blood flow through the aorta  150  also limits the amount of blood flow through the renal arteries  156 , 158 . In that regard, ostium  166  of the right renal artery  156  allows the flow of blood from the central lumen  160  into the right renal artery and on to the right kidney, while ostium  168  of the left renal artery  158  allows the flow of blood from the central lumen  160  into the left renal artery and on to the left kidney. 
     Proper placement of an endoluminal device, such as a graft or stent, within the vessel can be utilized to treat both conditions (i.e., aneurysm and stenosis). In the case of the aorta  150 , it is important to ensure that placement of the endoluminal device does not interfere with or block the flow of blood to the renal arteries  156 ,  158  in order to prevent damage to the kidneys. In that regard, it is important to ensure that the ostiums  166 ,  168  of the right and left renal arteries  156 ,  158 , respectively, remain unblocked. It can also be important to verify that the tissue of the aorta  150  is suitable for receiving the endoluminal device. 
     As shown in  FIG. 3 , a endograft  170  has been positioned within the lumen  160  of the aorta  150 . The endograft  170  is positioned over a guidewire  172  and translated along the length of the guidewire and into the aorta  150  in a retracted insertion configuration. In the illustrated embodiment, the endograft  170  follows the guidewire  172  through the right iliac  152  and into the lumen  160  of the aorta  150 . Similarly, the pigtail portion  120 , IVUS portion  118 , and elongated tubular member  102  of the catheter are positioned over a guidewire  174  and translated along the length of the guidewire into the aorta  150 . In the illustrated embodiment, the catheter follows the guidewire  174  through the left iliac  154  and into the lumen  160  of the aorta  150 . As shown, the pigtail portion  120  is maintained in the elongated configuration by the guidewire  174  during insertion. 
     Referring now to  FIG. 4 , with the catheter positioned within the aorta  150 , the guidewire  174  is retracted from at least the pigtail portion  120  to facilitate transition of the pigtail portion from elongated insertion configuration to the curved imaging configuration. In some instances, the guidewire  174  is removed entirely from the lumen of the catheter. Removal of the guidewire  174  increases the available volume of the lumen for introduction of contrast medium therethrough. In other instances, the guidewire  174  is only partially retracted such that a distal tip of the guidewire remains within the lumen of the catheter (e.g., within the IVUS portion  118  or within the elongated tubular member  102 ). In such instances, the contrast medium is introduced through the central lumen of the catheter around the guidewire  174  or through a separate lumen in the catheter. For example, in some instances the catheter includes a lumen within a wall of the catheter (in addition to the central lumen) for passing contrast medium or other fluid through the elongate tubular body  102  to the pigtail portion  120 . In some instances, the guidewire  174  itself includes a lumen such that the contrast medium can be introduced through the guidewire  174  to the pigtail portion  120 . 
     With the pigtail portion  120  in the curved configuration, a contrast medium is introduced into the aorta  150 . In some instances, the contrast medium is introduced to do spot angiography in order to facilitate precise placement and deployment of the endograft  170 . In that regard, one or more angiographic images of the vessel may be obtained. The angiographic images may include one or more spot angiographic images and/or one or more global or entire vessel angiographic images. 
     Before, after, or simultaneously with the angiographic imaging, IVUS imaging is performed utilizing the IVUS portion  118 . In the illustrated embodiment, IVUS imaging is utilized to identify the origin of the lowest renal artery to ensure that the endograft  170  is placed such that it does not block the ostiums  166 ,  168  of either of the renal arteries  156 ,  158 . The IVUS imaging is also utilized to ensure that the tissue adjacent the ostiums  166 ,  168  is healthy enough to receive the endograft  170 . In that regard, the IVUS imaging may be utilized to detect or identify lesions in the tissue. As a general matter, however, IVUS imaging may be utilized to obtain addition detail or information regarding any portion of the vessel. In some instances, a combination of the angiographic image(s) and the IVUS image(s) is utilized. In that regard, the angiographic image(s) and the IVUS image(s) are displayed together on a screen. For example, in some instances the angiographic image(s) and the IVUS image(s) are co-registered and displayed as disclosed in U.S. patent application Ser. No. 11/329,609 filed Jan. 11, 2006 and titled Vascular Image Co-registration, which is hereby incorporated by reference in its entirety. 
     Referring now to  FIG. 5 , after utilizing the information from the angiographic image(s) and the IVUS image(s) to properly position the endograft  170  within the aorta  150 , the endograft is expanded from its retracted insertion configuration to an anchoring configuration. As shown, in the expanded anchoring configuration a main body  176  of the endograft is positioned within the lumen  160  of the aorta  150  immediately adjacent to the ostiums  166 ,  168  of the renal arteries  156 ,  158  and an arm  178  of the endograft extends down through the aorta and into an upper portion of the right iliac  152 . As shown, once the endograft  170  has been expanded the guidewire  174  is reinserted through the pigtail portion  120  of the catheter such that the pigtail portion returns to its elongated configuration. With the pigtail portion  120  in the elongated configuration, the catheter is safely removed from the aorta  150  along the guidewire  174 . In some instances, the catheter is removed prior to full expansion of the endograft  170 . In other instances, the catheter is removed after full expansion and deployment of the endograft  170 . 
     Referring now to  FIG. 6 , the catheter has been reintroduced into the aorta  150  after placement of arm  180 . As shown, arm  180  engages the main body  176  of the endograft  170  and extends down through the aorta  150  and into an upper portion of the left iliac  154 . In the illustrated embodiment, the catheter has been reintroduced through the right iliac  152 . In that regard, the catheter is translated over guidewire  172  or another guidewire. In other instances, the catheter is reintroduced into the aorta  150  through the left iliac  154  over guidewire  174  or another guidewire. With the distal portion of the catheter positioned within the aorta, the guidewire is retracted to facilitate transition of the pigtail portion  120  to the curved configuration from the straight or elongated configuration. Contrast medium is introduced through the pigtail portion  120  in order to confirm patency of the renal arteries  156 ,  158  after expansion of the endograft using angiography and IVUS imaging. Further, angiographic imaging is utilized to ensure that there are no leaks associated with the endograft. Generally, the angiographic and IVUS imaging can be utilized after deployment of the endograft to ensure that the procedure has been carried out properly. If any problems (e.g., renal blockage, incomplete expansion of the endograft, leaks, improper placement, etc.) are detected in the angiographic or IVUS imaging, then the surgeon can address those problems at that time rather than waiting for indications of those problems to arise in a possibly life-threatening manner (e.g., kidney failure, heart attack, etc.). If the no problems are detected, then a guidewire is extended through the pigtail portion  120  of the catheter such that the pigtail portion returns to its elongated configuration to facilitate removal of the catheter along the guidewire. 
     In an alternative embodiment, the pigtail portion  120  is not fixedly attached to the IVUS portion  118  or the elongated tubular member  102  as described above. In one such embodiment, illustrated in  FIGS. 7 and 8 , an elongated tubular member  200  having imaging capabilities serves as a guiding catheter to a separate pigtail device  202 . In that regard, the elongated tubular member  200  includes a main body  204  that defines a lumen  206  extending along the length of the elongated tubular member  200 . Adjacent the distal end  208  of the elongated tubular member  200  is an imaging device housing  210 . In some instances, the imaging device housing  210  contains one or more ultrasound transducers or other imaging apparatus (not shown). The lumen  206  of the elongated tubular member  200  is sized to receive the pigtail device  202  such that the pigtail device  202  can be introduced through the lumen  206 . In that regard, the pigtail device  202  is inserted through the lumen  206  after placement of the elongated tubular member  200  within a vessel in some instances. In other instances, the pigtail device  202  is positioned within the lumen  206  and introduced into the vessel along with the elongated tubular member  200 . The pigtail device  202  includes a main body portion  212  that includes a plurality of openings  214  adjacent a distal end  216 . As shown in  FIG. 8 , once the pigtail device  202  is advanced beyond the distal end  208  of the elongated tubular member  200 , the pigtail device  202  reverts to its curved orientation. With the pigtail device  202  in the curved orientation, contrast media can be introduced into the vessel through openings  214 . 
     The configuration of  FIGS. 7 and 8  allows adjustment of the separation of the pigtail portion from the imaging portion. The ability to adjust the distance between the pigtail portion and the imaging portion facilitates simultaneous imaging of different portions of a vessel (i.e., one portion using IVUS imaging and another portion using angiographic imaging) and/or pullback of the imaging portion relative to the pigtail portion. For example, in one application, with the pigtail portion in the curved configuration an angiographic image is obtained by introducing contrast medium into the vessel through the pigtail portion. Simultaneously, before, or after the angiographic image is obtained the imaging portion of the elongated tubular member can be pulled back (e.g., using a pull back device) through the vessel, while the pigtail portion remains stationary, to obtain a sequence of IVUS images of the vessel. 
     In other embodiments, the pigtail portion  120  is movably secured to at least one of the elongated tubular member  102  and the IVUS portion  118  within a constrained range of motion. The distance between the pigtail portion and IVUS portion can be adjusted, but only within a range defined by the constrained range of motion. For example, in one instance, a proximal portion of the pigtail portion  120  defines a projection that is received within a recess of the inner surface of one or both of the IVUS portion  118  and the elongated tubular member  102  such that the proximal and distal boundaries of the recess define the allowed range of motion for the pigtail portion. In other instances, the pigtail portion  120  defines the recess and receives a projection from one or both of the IVUS portion  118  and the elongated tubular member  102 . Generally, any suitable mechanism for constraining the range of motion of the pigtail portion  120  relative to one or both of the IVUS portion  118  and the elongated tubular member  102  may be utilized. 
     Although illustrative embodiments have been shown and described, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure and in some instances, some features of the present disclosure may be employed without a corresponding use of the other features. It is understood that such variations may be made in the foregoing without departing from the scope of the present disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the present disclosure.