1. IntroductionWilhelm Röntgen’s X-ray image is still used as the real-timeimaging modality of choice in a majority of interventions [1]. Toassist interventionists during procedures pre-operative images canbe fused with X-ray. This 2D/3D overlay is obtained via alpha-blending; that is, a compromise in transparency between the data.Even with this shortcoming, the overlay is a gold-standard andwidely used in endovascular procedures, neuroradiology, oncol-ogy, coronary interventions, electrophysiology studies, and othertreatments. Although 3D imaging has the advantage of providingspatial information, intraoperative X-ray remains the focal pointand main interest for the interventionist since diagnosing steno-sis or aneurysms and positioning a catheter, guide wire, or stentcan only be performed by visualizing this modality. Luckily, experi-enced interventionists have substantial training interpreting X-rayalone