Curved planar reformatted CT angiography: Usefulness for the evaluation ofaneurysms at the carotid siphon

BACKGROUND AND PURPOSE: Three-dimensional CT angiography uses the data obta ined on a contrast-enhanced CT brain scan to generate 3D images of the intr acranial vasculature, We describe the methodology of curved planar reformat ting (CPR) for CT angiography and characterize its usefulness in the evalua tion of aneurysms at the carotid siphon, comparing it with the shaded surfa ce display technique (SSD). METHODS: Eighty-seven patients with suspected intracranial aneurysms at CT angiography were examined by conventional cerebral angiography, and the pat ients with aneurysm(s) at the carotid siphon were selected for study. For t hese patients, the visibility of the neck and fundus of the aneurysms on CT angiograms was compared for those obtained with SSD and those with CPR, an d observer reproducibility was evaluated with the kappa statistic. RESULTS: Eighteen patients were confirmed to have an aneurysm at the caroti d siphon on conventional angiograms, Seventeen aneurysms were depicted at C T angiography with SSD; 18 aneurysms with CPR, The number of visible aneury smal necks and fundi was nine and 12, respectively, with SSD; 18 and 18, re spectively, with CPR. CONCLUSION: CPR allows better demonstration of the body and neck of an aneu rysm at the carotid siphon, which has a tortuous course and is surrounded b y complex bony structures, CPR may be a useful adjunct for the evaluation o f aneurysms in this region.