We all know the significance of 3D views in angiographic evaluation, whether it be CTA, MRA or DSA.

3D DSA provides the best quality images of course, because of the superior spatial resolution, contrast resolution, selective vessel catheterisation, high contrast densities achieved etc. It has been used extensively and is now indispensable, in fact, a must for patients undergoing evaluation of aneurysms.

However, all these techniques have limitations when it comes to evaluation of the follow up imaging of clipped or coiled aneurysms.

CTA is OK for clipped aneurysms but not for coiled ones while CE-MRA hold good for the opposite.

3D DSA can also be marred by the artefacts. In fact, 2D DSA runs often are the best!. However, the recent advancements in the 3D reconstruction technology have made things easier.

Now we have 3d road mapping, fusion DSA, DynaCT etc. A noticeable one is the dual volume reconstruction in which the two acquired data volumes (the mask run and the contrast run) are reconstructed separately and then fused together, with each volume being modifiable individually to give the desired contrast, windowing and colour coding.

Illustrative examples:

Case 1: Immediate post coiling 3D angiogram to look for residue

Post coiling 3D angiogram with dual volume recon on an Acom aneurysm showing the coil mass in silver and the contrast filled arteries in golden brown. The aneurysm is well coiled with no residue. However the base of the coil mass is irregular indicating freshly done procedure. With time, base is likely to be covered up with endothelium and the arterial outline would become smooth.

Case 2: 2D and 3D angiograms in a post clipping regrown aneurysm

Routine angiograms showing a ventral ICA aneurysm with a surgical clip overlying the neck region. The exact relation ship of the clip with the aneurysm and the parent vessel is impossible to make out

Routine DSA image native view showing the clip and the arterial tree in relation to the bones.

3D run volume rendered image showing the aneurysm and the parent artery well with excellent depiction of the aneurysm morphology. However the clip is not seen as it has got subtracted. Note however that there is a groove over the neck of the aneurysm.

Dual  volume reconstruction images with dual colour coding showing the clip and the aneurysm with their interrelationship very nicely. the clip is totally free for the parent vessel and is abutting a very small portion of the aneurysm. It should be relatively easy to coil this aneurysm.

Case 3: Angiogram in a case of previously coiled Acom and left MCA aneurysms

2D DSA and 3D DSA run with volume rendering showing coiled left MCA and Acom aneurysms. There are contrast filled outpouchings seen at both locations again. However, it is difficult to evaluate the aneurysms, parent arteries and the coil mass inter-relationship. We do not know whether these are regrown aneurysms or new ones adjacent to the previously coiled ones.

Dual volume images show clearly that the MCA aneurysm has regrown and a fresh 'kissing’ aneurysm has come up at Acom adjacent to the previous one. clear visualisation of the parent artery, the arterial branches, aneurysm neck and the coil mass is apparent .