3T he ninth, tenth and eleventh nerves have much in common functionally and share a nucleus that originates in the medulla. They are therefore considered as a group and are evaluated as a region. Together, they enter the jugular foramen (1, 2). Detecting the individual cranial nerves in the intraforaminal portion of the jugular foramen is useful in diagnostic imaging; however, visualization using conventional magnetic resonance imaging (MRI) protocols does not provide adequate details of the individual nerves (3, 4). With the rapid development of MRI technology, newer 2D-3D, high spatial resolution, strong T2-weighted (T2W) sequences have been developed; these include 3D-CISS (three-dimensional constructive interference in steady state), 3D-MP-RAGE (three-dimensional magnetization-prepared rapid gradient-echo) and 3D-FIESTA (three-dimensional fast imaging employing steady-state acquisition) (3-7). Both balanced fast-field echo (bFFE) and 3D-T2W-driven equilibrium radiofrequency reset pulse (DRIVE) sequences can also provide heavily T2-weighted, good MR cisternographic images and can be used to evaluate cranial nerve nuclei and root entry zones (6)(7)(8).In this study, we aimed to assess the most efficient sequence for evaluating and visualizing the ninth, tenth and eleventh nerves. For this purpose, we evaluated images of this area on both sides of 100 patients. We applied bFFE, 3D-T2W-DRIVE, 2D-T2W-TSE and post-contrast T1-weighted (T1W) sequences and chose the best sequence for precisely visualizing all three nerves.
Materials and methodsSix hundred cranial nerves (9 th , 10 th and 11 th ) on both sides of 100 patients with complaints of tinnitus and hearing loss but without neurovascular compression syndromes were included in this study. All patients were referred to us with temporal MRI session requests by physicians. A total of 47 males and 53 females were analyzed between July and December 2008. The age range of the subjects was 14 to 74 years, and the mean age was 50 years. Informed consent was obtained prior to the MRI sessions. All MRI sections were performed using a 1.5-T Philips Nova Dual HP MRI scanner (16-channel Achiva Master, Eindhoven, Netherlands) with a 33 mT/m maximum gradient strength and a 180 mT/m per millisecond slew rate, using a standard head coil. We obtained MR images with bFFE, 3D-T2W DRIVE, 2D-T2W TSE and post-contrast T1W sequences. For the post-contrast series, 0.1 to 0.2 mmol/kg gadolinium-DTPA (Magnevist ® , Schering-Bayer, Leverkusen, Germany; and Omniscan™, GE Healthcare, Waukesha, Wisconsin, USA)) was administered.The parameters for the bFFE sequence were as follows: TR/TE/averages, 7.1/3.5 ms/3; flip angle, 50°; matrix, 308x320; field of view, 18x25 cm; reconstruction field of view, 83%; number of signals averaged (NSA,
MATERIALS AND METHODSBalanced fast-field echo (b-FFE), 3D-T2W DRIVE, T2W 2D TSE and post-contrast T1W MRI sequences were all applied and we tried to get the best sequence for the exact assessment of the 9 th , 10 th , and 11 th cranial nerves. Six hundred ner...