title: MR imaging of the trigeminal ganglion, nerve, and the perineural vascular plexus: normal appearance and variants with correlation to cadaver specimens.
abstract: OBJECTIVE
  MR imaging is the method of choice for evaluating the trigeminal nerve. Detection of abnormalities such as perineural tumor spread requires detailed knowledge of the normal MR appearance of the trigeminal nerve and surrounding structures. The purpose of this study was to clarify the normal MR appearance and variations of the trigeminal ganglion, maxillary nerve (V2), and mandibular nerve (V3) with their corresponding perineural vascular plexus.
  
  
  METHODS
  S: MR images obtained in 32 patients without symptoms referable to the trigeminal nerve were retrospectively reviewed. The trigeminal ganglion in Meckel's cave, V2 within the foramen rotundum, and V3 at the level of foramen ovale were assessed for visualization and enhancement. The configuration of the perineural vascular plexus was recorded. Correlation to cadaver specimens was made.
  
  
  RESULTS
  The trigeminal ganglion and V3 were observed to enhance in 3-4% of patients unilaterally. V2 and V3 were well visualized 93% of the time. The perineural vascular plexus of V2 was observed 91% of the time, and that of V3 in 97% of instances.
  
  
  CONCLUSIONS
  This study characterizes the normal MR appearance of the trigeminal ganglion and its proximal branches. The trigeminal ganglion, V2, and, V3 are almost always reliably seen on thin-section MR studies of the skull base. Enhancement of the perivascular plexus is routinely seen; however, enhancement of the trigeminal ganglion, V2, or V3 alone is seen only on occasion as supported by the avascular appearance of these anatomic structures in cadaver specimens.
authors.affiliation: Department of Radiology, JFK Medical Center, Atlantis, FL, USA.
authors.forename: Lorna Sohn
authors.initials: LS
authors.lastname: Williams
authors.forename: Ilona M
authors.initials: IM
authors.lastname: Schmalfuss
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Sistrom
authors.forename: Takuya
authors.initials: T
authors.lastname: Inoue
authors.forename: Ryusui
authors.initials: R
authors.lastname: Tanaka
authors.forename: Eduardo R
authors.initials: ER
authors.lastname: Seoane
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Mancuso
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010525:Peripheral Nerves / Q000000981:diagnostic imaging* / Q000473:pathology; D010900:Pituitary Diseases / Q000175:diagnosis; D011859:Radiography; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013223:Statistics as Topic; D012668:Trigeminal Ganglion / Q000000981:diagnostic imaging* / Q000473:pathology; D014276:Trigeminal Nerve / Q000000981:diagnostic imaging* / Q000473:pathology