Neurosurgery

Catheter Angiography

Catheter angiography has been the investigation that is definitive of a neuroradiologist. Whilst it is an invasive technique with significant complications, cerebral angiography has become progressively safer owing to DSA, non-ionic contrast media and improved catheters and guide wires.

Technique

The right femoral artery is punctured using the Seldinger technique. The catheter can then be advanced up to the aortic arch and then selectively into the required artery. The catheters are usually 4F or 5F in size and pre-shaped to facilitate selective catheterization. Once in position in the desired artery, the formal DSA is undertaken with the contrast injection by hand or mechanical pump [19]. Multiple projections are used to demonstrate the vasculature and images are obtained as far as the venous phase in several planes. Commonly, the internal carotid circulation is studied in lateral, postero-anterior 20o and oblique projection, e.g. 30o cranio-caudal, 30o lateral (Fig. 2.8a, b, c). The posterior circulation is studied in lateral and Townes' projection (30o fronto-occipital). Numerous supplementary projections can be performed according to which vessel is to be demonstrated. This is particularly important in the demonstration of aneurysms where a clear demonstration of the neck of the aneurysm is required, especially if endovascular treatment is to be considered. When available, three-dimensional angiography simplifies and improves the definition of this anatomy. In the study of SAH, all vessels need to be studied as multiple aneurysms are reported in up to 45% of cases. Reflux down a contralateral vertebral artery will often demonstrate the posterior inferior cerebellar artery (PICA) so that formal four-vessel angiography is not always necessary.

Complications

Local complications occur in about 5% of cases and range from self-limiting hematoma to fatal retroperitoneal hematoma. Vessel injury can result in pseudo-aneurysm, arteriovenous fistula and distal emboli.

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