Abstract: A position of an imaging plane relative to a catheter or other probe is aligned with tissue of interest. Ultrasound tissue images may be registered to the catheter position with minimal rotational ambiguity. The spatial position of an ablation catheter or other device with respect to the imaging plane is more accurately determined, allowing a physician to identify specific anatomy in the relative location of a catheter or catheters. Another alternative or additional approach to determining the position of an imaging plane is to determine the relative position of two or more catheters. A catheter associated with imaging is then moved or bent in a direction having a known spatial relationship with the imaging plane. The position of the catheter is relative to each is then determined again to determine the angle or position of the imaging plane.