Vascular branch characterization

#This disclosure relates generally to techniques for characterizing an area in a body. More particularly, the disclosure relates to characterizing vascular branches.

#Cardiac resynchronization therapy is achieved by positioning a lead in a traditional location in the right ventricle (RV), and by maneuvering a left ventricular (LV) pacing lead transvenously to a target wall in the left ventricle. Delivery of an LV lead to a desired location through the coronary sinus into the veins and their side branches surrounding the left ventricle is oftentimes a challenging procedure, requiring extensive fluoroscopic exposure for the patient and clinician. Venous anatomy is also highly variable, with some patients lacking suitable veins for permanent placement of a lead at a desired site, or requiring a lead to be maneuvered through sharp or even acute takeoff angles. Navigating a challenging anatomy may increase the possibility of complications such as coronary sinus or coronary vein dissection or perforation.

#Fluoroscopic imaging during transvenous LV lead implantation may involve recording one or more two-dimensional (2D) cine loops depicting objects such as the lead within the heart during implantation and at the final position. Soft tissues tend to form outlines, rather than explicitly visible objects. Although the lead may be visible, it is implanted based on comparing real-time views of the lead as it is advanced into position with a pre-recorded venogram acquired with contrast agent to highlight the coronary sinus and its venous tributaries, or by using anatomical landmarks such as the spine. However, it may still not be possible to reach a certain branch with a lead due to small vein size, acute angulation, or tortuosity of the vein. It is oftentimes challenging to know a priori whether a particular lead would fit well within a particular branch and in which branch the lead would have a low chance of dislodgement. Furthermore, there are a variety of lead models with different lengths and diameters available, but the implanting physician may not be able to determine before the actual implant procedure whether a particular lead will fit in a particular branch. Thus, it would be desirous to be able to characterize the coronary venous vasculature prior to the implantation of a permanent lead.

#FIG. 1 illustrates a first example of a flow diagram for characterizing a region of interest (ROI).

#FIG. 2 illustrates a second example of a flow diagram for characterizing a region of interest (ROI).

#FIG. 3 illustrates a third example of a flow diagram for characterizing a region of interest (ROI).

#The detailed description set forth below in connection with the appended drawings is intended as a description of various aspects of the present disclosure and is not intended to represent the only aspects in which the present disclosure may be practiced. Each aspect described in this disclosure is provided merely as an example or illustration of the present disclosure, and should not necessarily be construed as preferred or advantageous over other aspects. The detailed description includes specific details for the purpose of providing a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the present disclosure. Acronyms and other descriptive terminology may be used merely for convenience and clarity and are not intended to limit the scope of the present disclosure.

#In one aspect, the present disclosure relates to characterizing a region of interest (ROI) within the body of a patient. In one example, the length of a vascular branch is measured by advancing a sensor embedded on a tool along the length of the vascular branch and measuring the distance the sensor has traveled based on its trajectory. In one example, the sensor provides real-time position and orientation information. And, the sensor is embedded on an electrophysiologic tool (e.g., a guide wire, a catheter, a lead, stylet, etc.).

#Also, for example, the dimension of the vascular branch may be defined at multiple locations along the length based on the known thickness of the tool, or the vibratory motion of the tool within the vascular branch, or the spatial resolution of visual images and the number of pixels across the visual images. Visual images may include fluoroscopic images, X-ray images, computed tomography (CT) scan or computed axial tomography (CAT) scan images, magnetic resonance imaging (MRI) images, ultrasound images, etc. In one example, a geometric data set is generated prospectively based on the known tool sizes and the visual images that are taken.