CT angiography and MR angiography in the evaluation of carotid cavernous sinus fistula prior to embolization: a comparison of techniques.

BACKGROUND AND PURPOSE This study compared CT angiography (CTA), MR angiography (MRA), and digital subtraction angiography (DSA) in elucidating the size and location of carotid cavernous sinus fistulas (CCFs) before embolization treatment. METHODS This was a retrospective study of 53 patients with angiographically confirmed CCF. All patients underwent pre- and postcontrast-enhanced CTA and DSA, and 50 patients also underwent MRA. Two neuroradiologists rated detectability of the fistula tract as "good," "moderate," or "poor" in source images obtained by using each procedure. The chi(2) test was used to compare the imaging modalities with respect to their ability to detect fistulas. RESULTS CTA did not differ significantly from DSA (P = .155), and both CTA (P = .001) and DSA (P = .007) performed significantly better than MRA in the population as a whole. Differences in performance among the methods, however, depended upon the segmental location of the fistula along the internal carotid artery (ICA). CTA and MRA were similar in detection of CCFs in patients with a fistula at segment 3. CTA significantly outperformed MRA in patients with a fistula at segment 4, who accounted for approximately half of the population. CONCLUSIONS CTA source imaging has proved itself as useful as DSA for detecting CCFs. Of the 2 noninvasive techniques, CTA performed better than MRA in the population as a whole and in most patients whose fistula was located at segment 4 or 5 of the ICA.