3-DIMENSIONAL COMPUTED TOMOGRAPHIC ANGIOGRAPHY OF CEREBRAL ANEURYSMS

DESCRIBE OUR technique and results of dynamic, reconstructed, three-di mensional (3-D) computed tomographic (CT) angiography in our first 18 patients with either complex aneurysms, producing subarachnoid hemorrh age or the compression of neighboring structures, or small asymptomati c aneurysms, and assess the role of this technique in treatment planni ng. A dynamic, infused CT scan producing 1.5-mm cuts of the area of in terest was performed, and the two-dimensional images were reconstructe d in three dimensions with the ISG Allegro system (ISG Technologies, T oronto, Ontario, Canada). Results were compared with intra-arterial di gital subtraction angiography and magnetic resonance angiography. All aneurysms over 3 mm and half of the aneurysms less than or equal to 3 mm were demonstrated by 3-D CT angiography. The neck of the aneurysm, its relationship to the parent artery and associated branches, and its relationship to surrounding bony structures, such as the anterior cli noid, were also demonstrated. This was especially useful for ophthalmi c aneurysms. The 3-D image could be rotated on the screen to mimic the operative approach. The active, filling portion and the thrombosed pa rt of partially thrombosed, giant aneurysms could be seen on the same image, and the active, filling portion could be better appreciated wit h 3-D CT angiography than with magnetic resonance angiography. A parti ally treated, acrylic-coated aneurysm that could not be completely ass essed otherwise has been demonstrated by this technique. 3-D CT angiog raphy is useful in the evaluation of aneurysms, especially when the lo cal anatomy is obscured or distorted by its mass or by the anterior cl inoid. It was superior to magnetic resonance angiography in demonstrat ing the actively filling and thrombosed portions of giant, partially t hrombosed aneurysms and is useful in planning the surgical approach. 3 -D CT angiography may find a place in the assessment and treatment of complex aneurysms.