Systems, devices, and methods for locating a geometric plane within a patients vasculature, for example, an entry plane to a valve, are disclosed. In one example, a medical device can include a body member and an expandable element. The body member can extend along a longitudinal axis of the medical device and at least partially define a lumen. The body member can include at least one opening disposed in fluid communication with the lumen. The expandable element can include at least two radiographic markers and can be movable between at least a first configuration and a second configuration. The at least two radiographic markers can be disposed within the lumen when the expandable element is in the first configuration. The at least two radiographic members can be disposed outside of the lumen and can be radially offset from the longitudinal axis when the expandable element is in the second configuration.
