الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
CT angiography has become an important technique for post-clipping evaluation. It can be used to assess arteries as small as two millimeters in diameter; moreover the 3-D reconstructed images can be viewed from an unlimited number of angles. CTA is faster, less expensive and more widely available and also can be used in patients with aneurysmal clips. These advantages along with the non-invasive nature of the technique and reduced scanning time have brought CT angiography into prominence in the arena of vascular imaging.
The aim of this work to is to assess the role of computed tomography angiography (CTA) in the follow-up examination after intracranial aneurysmal clipping. This study was conducted on fifteen consecutive patients (nine females and six males) with surgically clipped cerebral aneurysms. The age of the patients was ranging from 43 to 71 years. All the patients underwent complete history taking, clinical examination and post-operative CTA examination to prove the feasibility of CTA in the follow up of surgically clipped aneurysm. Ten aneurysms were intact before clipping operation and treated electively while five aneurysms were ruptured.
The distribution of the studied clipped aneurysms was; ten involving the MCA (six at the left side and four at the right side), three involving the Acom and two involving the Pcom. Twelve patients had one clip, two patients had two clips and one patient had three clips.
Post-operative CT findings were: encephalomalacic changes in two patients, ischemic infarction sequel to clipping in one patient, extra-axial air and fluid collection sequel to operative intervention in two patients and right lateral ventricle shunt tube in one patient. The evolving CTA findings in the follow up study were; complete occlusion of the MCA by three surgical clips in one patient and spasm of A1 and M1 segments in one patient.
Clip elimination workstation technique succeeded to remove the clip in thirteen patients without pseudo-stenosis. It showed pseudo-stenosis in two patients that didn’t affect the image interpretation.
Beam hardening artifact was seen in four patients, three of them showed minimal artifact that didn’t affect image interpretation. Severe artifact was noted in one patient with lack of ability to assess the surrounding vasculature.
Fourteen CTA studies were adequately interpreted as regards adequate obliteration of the neck of aneurysm with good visualization of the adjacent vessels. One CTA study was difficult to interpret due to dense artifact in the vicinity of the aneurysm.
CTA was able to identify variations of circle of Willis components accounting for 46.2%. Hypoplasia of the segments was the most recurrent accounting for about 20%. Posterior cerebral artery was the commonest vessel to be affected accounting for 13.3%.
CTA techniques in the form of conventional CTA, MIP, 3D-CTA and CTA with elimination of the clip are all required together to reach the full correct diagnosis. The use of CTA as a follow up tool for cerebral aneurysm clipped with titanium clip is strongly recommended.