Type:
Educational Exhibit
Keywords:
Neuroradiology brain, Interventional vascular, Vascular, Catheter arteriography, Fluoroscopy, MR, Angioplasty, Stents, Catheters, Arteriovenous malformations, Aneurysms, Embolism / Thrombosis
Authors:
D. Ruijters, R. Homan, P. Mielekamp, D. Babic; Best/NL
DOI:
10.1594/ecr2012/C-1183
Background
Traditional roadmapping is based on the superimposition of digital subtraction angiography (DSA) and the live fluoroscopy images.
The DSA technique has been developed in the 1930's,
and has first been used in interventional treatment in the 1960's.
The DSA images show the vessel lumen filled with iodinated contrast medium,
while the fluoroscopy images show the current location of the endovascular devices.
It provides the vascular context to the real-time fluoroscopy and therefore helps to lowers the risk of inadvertent events,
while lowering the use of iodinated contrast medium [1].
The roadmap is limited by its static projection incidence.
Tortuous cerebral vessels and complex lesion morphology (e.g.,
complex aneurysms,
AVM's etc.) often require many different working projections,
which leads to extra contrast injections for new roadmaps.
Dynamic 3D roadmap significantly improves on the traditional roadmapping technique by using a cone-beam CT reconstruction to supplement the fluoroscopy image with the 3D vasculature.
This 3D model stays valid for different projection angles and focal distances,
and therefore no new contrast injections are required [2,3].
CT/MR Roadmapping (Philips Heathcare,
Best,
the Netherlands) is an extension of the dynamic 3D roadmap.
It involves an additional co-registration step of the multimodal data into the frame of reference of the cone-beam CT dataset.
The technique is illustrated by the figures in the sidebar.
Figure 2 shows an AVM and impacted brain tissue in a MR acquisition.
The live fluoroscopy image without contrast medium in Figure 3 shows the guide wire,
but does not reveal its relation to the vasculature and the soft-tissue.
The 3D dynamic roadmap in Figure 4 adds the 3D vascular context to the live fluoroscopy image. Figure 5 shows the fluoroscopy image,
the 3DRA vasculature and a slab from the MR data.
The MR slab is positioned parallel to the view port at the guide wire tip.