title: Visualization of the Abducens Nerve in its Petroclival Segment Using Contrast-Enhanced FIESTA MRI: The Size of the Petroclival Venous Confluence Affects Detectability.
abstract: OBJECTIVE
  Visualization of the abducens nerve in its petroclival segment still remains challenging. We aimed to investigate the detectability of the petroclival segment of the abducens nerve and to evaluate the role of the size of the petroclival venous confluence (PVC) in the visibility of the nerve using contrast-enhanced fast imaging employing steady-state acquisition (FIESTA) magnetic resonance imaging (MRI).
  
  
  METHODS
  We retrospectively evaluated the contrast-enhanced FIESTA images of 237 patients (female/male: 127/110; mean age: 49.0 ± 14.7). Two radiologists divided the imaging findings of the petroclival segments of the abducens nerves into three groups: 0 (not visualized), 1 (partially visualized), and 2 (completely visualized). Another radiologist measured the anteroposterior diameter of the PVC from the clival bony surface to the inner layer of dura at the dural entrance level of the abducens nerve. One-way analysis of variance, Tukey's test, and receiving operating curve analysis were performed.
  
  
  RESULTS
  Among 474 abducens nerves, 76 were classified as group 0 (76/474, 16.03 %), 100 were classified as group 1 (100/474, 21.10 %), and 298 were classified as group 2 (298/474, 62.87 %). There was significant difference in mean anteroposterior diameters of the PVC for each group (group 0, 0.95 mm; group 1, 1.80 mm; group 2, 2.51 mm). The cut-off values for the differentiation of group 0 from group 1 and group 1 from group 2 were found to be 1.35 and 2.09 mm, respectively.
  
  
  CONCLUSIONS
  Abducens nerve in its petroclival segment can be reliably identified using contrast-enhanced FIESTA MRI especially in those with a greater anteroposterior diameter of the PVC.
authors.affiliation: Faculty of Medicine, Department of Radiology, Mersin University, 34. Cadde, Çiftlikköy Kampüsü, 33343, Mersin, Turkey. anilozgur@yahoo.com.
authors.forename: A
authors.initials: A
authors.lastname: Özgür
authors.affiliation: Faculty of Medicine, Department of Radiology, Mersin University, 34. Cadde, Çiftlikköy Kampüsü, 33343, Mersin, Turkey.
authors.forename: K
authors.initials: K
authors.lastname: Esen
authors.affiliation: Faculty of Medicine, Department of Radiology, Mersin University, 34. Cadde, Çiftlikköy Kampüsü, 33343, Mersin, Turkey.
authors.forename: E
authors.initials: E
authors.lastname: Kara
authors.affiliation: Faculty of Medicine, Department of Biostatistics, Mersin University, Mersin, Turkey.
authors.forename: G O
authors.initials: GO
authors.lastname: Temel
mesh_terms: D000010:Abducens Nerve / Q000033:anatomy & histology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002550:Cerebral Veins / Q000033:anatomy & histology*; D003287:Contrast Media; D003388:Cranial Fossa, Posterior / Q000033:anatomy & histology / Q000098:blood supply; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging / Q000379:methods*; D010579:Petrous Bone / Q000033:anatomy & histology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: Abducens nerve; FIESTA; MRI; Petroclival venous confluence