Normal cranial nerves in the cavernous sinuses: contrast-enhanced three-dimensional constructive interference in the steady state MR imaging.

BACKGROUND AND PURPOSE Three-dimensional (3D) constructive interference in steady state (CISS) MR imaging is useful for demonstrating cranial nerves (CNs) in the cistern. The purpose of this study was to evaluate normal CNs III, IV, V1, V2, and VI in the cavernous sinuses by using contrast-enhanced, three-dimensional (3D), Fourier transformation CISS MR imaging. METHODS In 76 normal cavernous sinuses from 38 patients, detectability of CNs III-VI in the bilateral cavernous sinuses was evaluated by using contrast-enhanced 3D CISS MR imaging. In 40 cavernous sinuses from 20 patients, contrast-enhanced 3D CISS and contrast-enhanced T1-weighted MR imaging were compared for the detectability of these CNs. RESULTS Each CN was separately demonstrated, and in 11 patients (29%), all CNs in the cavernous sinuses were identified on contrast-enhanced 3D CISS MR imaging. The images depicted the intracavernous segments of CNs III, IV, V1, V2, and VI in 76 (100%), 46 (61%), 70 (92%), 67 (88%), and 73 (96%) of the 76 sinuses, respectively. In comparison of imaging techniques, contrast-enhanced 3D CISS MR imaging had a detection rate significantly higher than that of enhanced T1-weighting imaging (P < .05) in all CNs except for CN III, which was detected in 100% of cases with both techniques. CONCLUSION Contrast-enhanced 3D CISS MR imaging provides clear images of each CN in the cavernous segment. This useful method may contribute to the diagnosis of diseases involving the cavernous sinuses, such as Tolosa-Hunt syndrome.