Comparison of 2D and 3D digital subtraction angiography in evaluation of intracranial aneurysms. 
Although digital subtraction angiography (DSA) is considered the criterion standard for depiction of intracranial aneurysms, it is often difficult to determine the relationship of overlapping vessels to aneurysms when using 2D DSA.  We compared 2D and 3D DSA in evaluation of intracranial aneurysms.  Thirty-six consecutive patients with cerebral aneurysms underwent 2D and 3D DSA.  After standard 2D DSA, rotational DSA was performed.  Maximum intensity projection (MIP) and shaded surface display (SSD) images were created from the rotational DSA data sets.  All images were assessed randomly for overall image quality, presence of aneurysm, presence of aneurysmal lobulation, visualization of aneurysmal neck, and relationship to adjacent vessels.  Data analysis was conducted for 40 aneurysms treated by clip placement.  One aneurysm that was not detected at 2D DSA was classified as uncertain on the basis of rotational DSA.  All aneurysms were classified as probably or definitively present on the basis of MIP and SSD findings.  Overall image quality of rotational DSA, MIP, and SSD was statistically inferior to that of the standard 2D DSA for visualization of distal arteries.  However, MIP and SSD images were significantly superior to those of standard 2D DSA for all other evaluations.  For detection of lobulation, SSD images were significantly superior to other images, and for visualization of aneurysmal neck and relationship to neighboring arteries, SSD images were significantly superior to those of rotational DSA.  For evaluation of the relationship to neighboring arteries, MIP images were significantly superior to those of rotational DSA.  Three-dimensional DSA, especially SSD, provided more detailed information for evaluating cerebral aneurysms than did standard 2D and rotational DSA.