Trigeminal nerve: What the radiologist should know

Transcription

1 Trigeminal nerve: What the radiologist should know Award: Cum Laude Poster No.: C-1725 Congress: ECR 2016 Type: Educational Exhibit Authors: H. Nejadhamzeeigilani, T. Buende Tchokouako, J. MacmullenPrice, I. Craven, D. J. Warren, S. Currie; Leeds/UK Keywords: Neuroradiology brain, MR, Education, Pathology DOI: /ecr2016/C-1725 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 63

2 Learning objectives The purpose of this educational exhibit is to: review the normal anatomy of the trigeminal nerve. highlight a variety of pathologies that can effect the trigeminal nerve. signify the importance of a segmental approach to aide identification of the trigeminal nerve and it's pathologies on magnetic resonance (MR) imaging, for the general radiologist. Page 2 of 63

3 Background In this section we will discuss the functional anatomy and important anatomical landmarks that will assist the general radiologist to identify the trigeminal nerve throughout its course. A. FUNCTIONAL ANATOMY (Figure 1-3) The functional relevance of the trigeminal nerve is somatosensory supply to the face, oral and nasal cavities, the teeth and majority of the scalp and motor supply to the masticatory and some other facial muscles. It is also responsible for proprioceptive input from the masticatory and extra-ocular muscles. Figures 1-3 demonstrate the functional anatomy of the trigeminal nerve following its division into the ophthalmic (V1), maxillary (V2) and mandibular (V3) divisions. Fig. 1: Diagram demonstrating V1 course. Page 3 of 63

4 References: TSdocs, many thanks to Naeem Majid, Saba Fatima, Hina Fatima Fig. 2: Diagram demonstrating V2 course. References: TSdocs, many thanks to Naeem Majid, Saba Fatima, Hina Fatima Page 4 of 63

5 Fig. 3: Diagram demonstrating V3 course. References: TSdocs, many thanks to Naeem Majid, Saba Fatima, Hina Fatima B. STRUCTURAL/GROSS ANATOMY B1 Brainstem segment (Figure 4) The trigeminal nerve arises from one motor nucleus and three sensory nuclei: Page 5 of 63

6 > Principal sensory nucleus is situated in the dorsolateral pontine tegmentum and is responsible for tactile sensation from V1-V3. > Mesencephalic nucleus is located at the lateral region of the periaqueductal grey matter in the midbrain. It is responsible for proprioception of various muscles and joints including the extra-ocular muscles and the temporo-mandibular joints > Spinal nucleus extends inferiorly through the medulla and into the upper segments of the cervical spinal cord's dorsal horns. Its main function is pain and temperature sensory input from V1-V3. The second and third order neurons from these nuclei extend to the thalamus and the cerebral cortex respectively. > Motor nucleus lies anteromedial to the principal sensory nucleus in the upper pons and innervates motor function to the masticatory muscle, mylohyoid, tensor tympani and tensor veli palatini. Page 6 of 63

7 Fig. 4: T1 sagittal oblique showing right trigeminal nerve emanating from the pons. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK B2 Cisternal segment (Figure 5) The trigeminal nerve exits the ventral aspect of the pons as two trunks on each side; a large sensory root and a smaller, antero-medial to the former, motor root. On its exit from the pons, the trigeminal nerve traverses the pre-pontine cistern antero-laterally, just medial to the petrous apex, at which point it enters the middle cranial fossa and Meckel's cave via the porus trigeminus opening of the dura. The point of change from central to Page 7 of 63

8 peripheral myelin, just prior to its exit from the pons, is referred to as the root entry zone (REZ). Fig. 5: Figure 5.1, 5.2 and 5.3 Axial, sagittal and coronal CISS images: a=fourth ventricle, b=main sensory nucleus, c=main motor nucleus, d=root entry zone, e=porus trigeminus, f=cisternal segment, g=meckel's cave References: Leeds Teaching Hospitals NHS Trust - Leeds/UK B3 Meckel's cave segment Meckel's cave (also called trigeminal cave or cavum trigeminale) is a cerebrospinal fluid containing pouch lined with dura. It lies immediately lateral to the cavernous sinus and is continuous with the pre-pontine cistern. Contained within it is the trigeminal ganglion (also referred as Gasserian or semilunar ganglion) from which the three branches of the trigeminal nerve arise from: V1, V2 and V3. Apart from the proprioceptive fibres, the cell bodies of all sensory fibres are situated in this ganglion. The motor trunk runs inferiorly Page 8 of 63

9 to the ganglion and takes the course of V3, bypassing the cavernous sinus, in order to reach the masticator space. B4 Cavernous segment V1 and V2 pass through the lateral wall of the cavernous sinus from a posterior to anterior approach and pass lateral to the cavernous carotid artery and abducens nerve and inferior to the trochlear nerve. B5 Skull base segment The three branches of the trigeminal nerve exit the calvarium from different foramina: > V1 traverses the superior orbital fissure towards the orbit. (Figure 6) > V2 reaches the pterygopalatine fossa through the foramen rotundum. (Figure 7-9) > V3 exits the intracranial compartment through the foramen ovale to reach the infratemporal fossa. (Figure 10-11) Page 9 of 63

10 Fig. 6: Figure Coronal and axial CT: arrows demonstrate location of superior orbital fissures. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 10 of 63

11 Fig. 7: Figure Coronal and axial CT: arrows demonstrate location of foramen rotundum. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 11 of 63

12 Fig. 8: Axial CT: arrows demonstrate location of pterygopalatine fossa. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 12 of 63

13 Fig. 9: Figure Axial and coronal T1: arrows demonstrate V2 traversing foramen rotundum. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 13 of 63

14 Fig. 10: Figure Axial and coronal CT: arrows demonstrate location of foramen ovale. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 14 of 63

15 Fig. 11: Figure Axial and coronal T1: arrows demonstrate V3 traversing foramen ovale. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK B6 Extra-cranial segment >V1: The ophthalmic division gives off three further branches: the frontal, lacrimal and nasociliary nerves which are responsible for sensory input from the globe, nose, forehead and scalp. The supraorbital nerve, which is a terminal branch of the frontal nerve, traverses the supraorbital foramen whilst the supratrochlear nerve, which is a branch of the frontal nerve, traverses the supratrochlear foramen. (Figure 12) >V2: The maxillary division gives off four branches in the pterygopalatine fossa: the zygomatic, superior alveolar, meningeal and pterygopalatine nerves. The continuation of its main root into the infraorbital canal via the infraorbital foramen is the resultant infraorbital nerve. The inferior orbital fissure which separates the posterior aspect of the lateral wall and floor of the orbits, contains the zygomatic and pterygopalatine nerves. (Figure 13) >V3: The mandibular division has both sensory and motor functions. The sensory component is grossly responsible for input from the lower third of the face and branches into the inferior alveolar, lingual and auriculotemporal nerves. The motor component innervates the tensor veli palatini, tensor tympani, anterior belly of digastric muscle and masticator muscles via its branches, the masticator and mylohyoid nerve. (Figure 14-15) Page 15 of 63

16 Fig. 12: Figure Axial CT: white arrows demonstrate supraorbital foramina, black arrows demonstrate supratrochlear foramina. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Fig. 13: Figure Axial & coronal CT: arrows demonstrate infraorbital fissures. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 16 of 63

17 Fig. 14: Figure D CT reconstructions of (14.1) the base of the skull showing foramen ovale (black arrow), (14.2) the lateral aspect of the skull and face demonstrating the position of the infratemporal fossa (green arrow) where V3 enters after leaving foremen ovale and (14.3) the medial aspect of the right mandible showing the mandibular foramen (short black arrow) and canal (long black arrow) - site of the inferior alveolar nerve (V3). References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 17 of 63

18 Fig. 15: 3D CT reconstruction of the mandible showing the mental foramina (white arrows): point of exit for the mental nerves (from the inferior alveolar nerves, V3). References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 18 of 63

19 Images for this section: Fig. 1: Diagram demonstrating V1 course. TSdocs, many thanks to Naeem Majid, Saba Fatima, Hina Fatima Page 19 of 63

20 Fig. 2: Diagram demonstrating V2 course. TSdocs, many thanks to Naeem Majid, Saba Fatima, Hina Fatima Page 20 of 63

21 Fig. 3: Diagram demonstrating V3 course. TSdocs, many thanks to Naeem Majid, Saba Fatima, Hina Fatima Page 21 of 63

22 Fig. 4: T1 sagittal oblique showing right trigeminal nerve emanating from the pons. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 22 of 63

23 Fig. 5: Figure 5.1, 5.2 and 5.3 Axial, sagittal and coronal CISS images: a=fourth ventricle, b=main sensory nucleus, c=main motor nucleus, d=root entry zone, e=porus trigeminus, f=cisternal segment, g=meckel's cave Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 23 of 63

24 Fig. 6: Figure Coronal and axial CT: arrows demonstrate location of superior orbital fissures. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 24 of 63

25 Fig. 7: Figure Coronal and axial CT: arrows demonstrate location of foramen rotundum. Leeds Teaching Hospitals NHS Trust - Leeds/UK Fig. 8: Axial CT: arrows demonstrate location of pterygopalatine fossa. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 25 of 63

26 Fig. 9: Figure Axial and coronal T1: arrows demonstrate V2 traversing foramen rotundum. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 26 of 63

27 Fig. 10: Figure Axial and coronal CT: arrows demonstrate location of foramen ovale. Leeds Teaching Hospitals NHS Trust - Leeds/UK Fig. 11: Figure Axial and coronal T1: arrows demonstrate V3 traversing foramen ovale. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 27 of 63

28 Fig. 12: Figure Axial CT: white arrows demonstrate supraorbital foramina, black arrows demonstrate supratrochlear foramina. Leeds Teaching Hospitals NHS Trust - Leeds/UK Fig. 13: Figure Axial & coronal CT: arrows demonstrate infraorbital fissures. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 28 of 63

29 Fig. 14: Figure D CT reconstructions of (14.1) the base of the skull showing foramen ovale (black arrow), (14.2) the lateral aspect of the skull and face demonstrating the position of the infratemporal fossa (green arrow) where V3 enters after leaving foremen ovale and (14.3) the medial aspect of the right mandible showing the mandibular foramen (short black arrow) and canal (long black arrow) - site of the inferior alveolar nerve (V3). Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 29 of 63

30 Fig. 15: 3D CT reconstruction of the mandible showing the mental foramina (white arrows): point of exit for the mental nerves (from the inferior alveolar nerves, V3). Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 30 of 63

31 Findings and procedure details Pathologies can affect the trigeminal nerve at any level along its course. At its origin the trigeminal nerve may be affected by cerebrovascular disease, inflammatory disease, neoplasia, infection, and vascular malformations. At the level of the pre-pontine cistern pathologies that cause compressive deformity of the nerve dominate, such as tortuous or ectatic vessels and cerebellopontine angle (CPA) neoplasms. Cavernous sinus and basal skull pathologies that affect the trigeminal nerve include aneurysms, neoplasms such as meningioma, schwannoma, lymphoma, and inflammatory disease such as sarcoidosis. In this section we will demonstrate pathologies from the trigeminal nuclei out to the peripheral divisions in a segmental anatomical approach. Page 31 of 63

32 Fig. 16: Figure MR images demonstrating metastasis at the right trigeminal nerve nucleus from an endometrial primary, as well as two cerebral metastases Axial T1, Axial T1 post gadolinium (GAD), Axial T2 post GAD, 16.4 Sagittal T2 post GAD, 16.5& Coronal T1 post GAD References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 32 of 63

33 Fig. 17: Figure Cross-sectional studies demonstrating left root entry zone lipoma Axial T1, Axial T2, Axial CISS, Coronal FLAIR, 17.5 Axial CT demonstrating negative Hounsfield units of lesion, Sagittal CISS, 17.7 Coronal CISS References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 33 of 63

34 Fig. 18: Figure MR images demonstrating a right pontine demyelinating plaque in a patient with multiple sclerosis presenting with trigeminal neuralgia Axial T2, 18.2 Axial FLAIR, 18.3 Axial ADC-DWI, 18.4 Axial B1000 of DWI showing restricted diffusion suggestive of active inflammation, 18.5, Sagittal T2 References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 34 of 63

35 Fig. 19: Figure MR images demonstrating right cavernoma with developmental venous anomaly (DVA) Axial T1 showing subacute blood in cavernoma, 19.2 Axial T2, 19.3 Axial SWI showing signal dropout from cavernoma and superginous vessels from DVA. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 35 of 63

36 Fig. 20: Figure MR images demonstrating right trigeminal neuroma from pons to Meckel's cave and through right foramen ovale Axial T1 post GAD fat saturated showing neuroma arising and coursing to an expanded Meckel's cave Axial T2 showing an expanded right foramen ovale Coronal T1 post GAD showing an expanded right Meckel's cave and foramen ovale. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 36 of 63

37 Fig. 21: Figure MR images demonstrating pre-pontine epidermoid tumour Axial T1 volume post GAD, 21.2 Axial T2, 21.3 ADC, 21.4 B1000 of DWI. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 37 of 63

38 Fig. 22: Figure MR images demonstrating left cerebellopontine angle meningioma compressing left trigeminal nerve Axial T1 post GAD, 22.2 Coronal T1 post GAD References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 38 of 63

39 Fig. 23: Figure MR images demonstrating left CPA meningioma with compressive denervation of the trigeminal motor branches Axial T1 post GAD, 23.2 Coronal T1 post GAD, 23.3 Axial T2 showing asymmetric atrophy of the left masticatory muscles. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 39 of 63

40 Fig. 24: Figure MR images demonstrating right trigeminal nerve root compression by superior cerebellar artery branch Sagittal CISS normal left nerve root, 24.1 Sagittal shows compressive deformity upon the cisternal component of the right trigeminal nerve (long blue arrow) by a serpinginous branch of the right superior cerebellar artery (short blue arrow), 24.3 Axial CISS. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 40 of 63

41 Fig. 25: Figure MR images of a patient with adenoid cystic tumour with perineural spread along the right trigeminal nerve. Fig 25.1 (axial STIR) and Figs (axial T1 fat saturated post GAD) show expanded and enhancing tumour running from the root entry zone, through Meckel's cave and the cavernous sinus, into the pterygopalatine fossa. Also note tumour spread through the infraorbital fissure (white arrow Fig 25.2) through foramen rotundum (blue arrow Fig 25.3) and through foramen ovale (green arrow Fig 25.4, coronal T1 fat saturated post GAD). References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 41 of 63

42 Fig. 26: Figure MR images demonstrating right trigeminal neuroma Axial STIR, neuroma extending from Meckels cave through foramen rotundum into pterygopalatine fossa and through the right infraorbital foramen Axial T2, 26.3 Sagittal T1. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 42 of 63

43 Fig. 27: Figure MR images demonstrating large right trigeminal schwannoma Axial T2 schwannoma extending through expanded right foramina of ovale and rotundum Sagittal FLAIR, 27.3 Coronal T1, 27.4 Coronal T1 post GAD. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 43 of 63

44 Fig. 28: Figure MR images demonstrating left middle cranial fossa meningioma extending through expanded left foramen rotundum and into left pterygopalatine fossa Axial T1 post GAD, 28.2 Sagittal T1 post GAD. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 44 of 63

45 Fig. 29: Figure MR images of a child with metastatic and leptomeningeal spread of CNS-type primitive neuroectodermal tumour (PNET) of the pineal gland (pineoblastoma). Fig 29.3, sagittal T1 post GAD shows the original pineal gland tumour with additional bulky metastatic deposits in the sella and at the foramen of Magendie. Figs 29.1 & 29.2 (axial volume T1 post GAD) demonstrate abnormal enhancement and expansion of the trigeminal nerves bilaterally but worse on the right. Note the expanded right Meckel's cave (black arrow) and also the leptomeningeal spread involving the VII and VIII nerve complexes bilaterally (white arrows). References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 45 of 63

46 Fig. 30: Figure MR images demonstrating right trigeminal neuroma expanding the right foramen ovale Axial T1 post GAD fat saturated showing part cystic part solid enhancing lesion expanding and extending through right foramen ovale Coronal T1 post GAD fat saturated. References: Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 46 of 63

47 Images for this section: Fig. 16: Figure MR images demonstrating metastasis at the right trigeminal nerve nucleus from an endometrial primary, as well as two cerebral metastases Axial T1, Axial T1 post gadolinium (GAD), Axial T2 post GAD, Sagittal T2 post GAD, 16.5& Coronal T1 post GAD Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 47 of 63

48 Fig. 17: Figure Cross-sectional studies demonstrating left root entry zone lipoma Axial T1, Axial T2, Axial CISS, Coronal FLAIR, Axial CT demonstrating negative Hounsfield units of lesion, Sagittal CISS, Coronal CISS Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 48 of 63

49 Fig. 18: Figure MR images demonstrating a right pontine demyelinating plaque in a patient with multiple sclerosis presenting with trigeminal neuralgia Axial T2, 18.2 Axial FLAIR, 18.3 Axial ADC-DWI, 18.4 Axial B1000 of DWI showing restricted diffusion suggestive of active inflammation, 18.5, Sagittal T2 Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 49 of 63

50 Fig. 19: Figure MR images demonstrating right cavernoma with developmental venous anomaly (DVA) Axial T1 showing subacute blood in cavernoma, 19.2 Axial T2, 19.3 Axial SWI showing signal dropout from cavernoma and superginous vessels from DVA. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 50 of 63

51 Fig. 20: Figure MR images demonstrating right trigeminal neuroma from pons to Meckel's cave and through right foramen ovale Axial T1 post GAD fat saturated showing neuroma arising and coursing to an expanded Meckel's cave Axial T2 showing an expanded right foramen ovale Coronal T1 post GAD showing an expanded right Meckel's cave and foramen ovale. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 51 of 63

52 Fig. 21: Figure MR images demonstrating pre-pontine epidermoid tumour Axial T1 volume post GAD, 21.2 Axial T2, 21.3 ADC, 21.4 B1000 of DWI. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 52 of 63

53 Fig. 22: Figure MR images demonstrating left cerebellopontine angle meningioma compressing left trigeminal nerve Axial T1 post GAD, 22.2 Coronal T1 post GAD Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 53 of 63

54 Fig. 23: Figure MR images demonstrating left CPA meningioma with compressive denervation of the trigeminal motor branches Axial T1 post GAD, 23.2 Coronal T1 post GAD, 23.3 Axial T2 showing asymmetric atrophy of the left masticatory muscles. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 54 of 63

55 Fig. 24: Figure MR images demonstrating right trigeminal nerve root compression by superior cerebellar artery branch Sagittal CISS normal left nerve root, 24.1 Sagittal shows compressive deformity upon the cisternal component of the right trigeminal nerve (long blue arrow) by a serpinginous branch of the right superior cerebellar artery (short blue arrow), 24.3 Axial CISS. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 55 of 63

56 Fig. 25: Figure MR images of a patient with adenoid cystic tumour with perineural spread along the right trigeminal nerve. Fig 25.1 (axial STIR) and Figs (axial T1 fat saturated post GAD) show expanded and enhancing tumour running from the root entry zone, through Meckel's cave and the cavernous sinus, into the pterygopalatine fossa. Also note tumour spread through the infraorbital fissure (white arrow Fig 25.2) through foramen rotundum (blue arrow Fig 25.3) and through foramen ovale (green arrow Fig 25.4, coronal T1 fat saturated post GAD). Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 56 of 63

57 Fig. 26: Figure MR images demonstrating right trigeminal neuroma Axial STIR, neuroma extending from Meckels cave through foramen rotundum into pterygopalatine fossa and through the right infraorbital foramen Axial T2, 26.3 Sagittal T1. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 57 of 63

58 Fig. 27: Figure MR images demonstrating large right trigeminal schwannoma Axial T2 schwannoma extending through expanded right foramina of ovale and rotundum Sagittal FLAIR, 27.3 Coronal T1, 27.4 Coronal T1 post GAD. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 58 of 63

59 Fig. 28: Figure MR images demonstrating left middle cranial fossa meningioma extending through expanded left foramen rotundum and into left pterygopalatine fossa Axial T1 post GAD, 28.2 Sagittal T1 post GAD. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 59 of 63

60 Fig. 29: Figure MR images of a child with metastatic and leptomeningeal spread of CNS-type primitive neuroectodermal tumour (PNET) of the pineal gland (pineoblastoma). Fig 29.3, sagittal T1 post GAD shows the original pineal gland tumour with additional bulky metastatic deposits in the sella and at the foramen of Magendie. Figs 29.1 & 29.2 (axial volume T1 post GAD) demonstrate abnormal enhancement and expansion of the trigeminal nerves bilaterally but worse on the right. Note the expanded right Meckel's cave (black arrow) and also the leptomeningeal spread involving the VII and VIII nerve complexes bilaterally (white arrows). Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 60 of 63

61 Fig. 30: Figure MR images demonstrating right trigeminal neuroma expanding the right foramen ovale Axial T1 post GAD fat saturated showing part cystic part solid enhancing lesion expanding and extending through right foramen ovale Coronal T1 post GAD fat saturated. Leeds Teaching Hospitals NHS Trust - Leeds/UK Page 61 of 63

62 Conclusion Understanding of the anatomy and function of the trigeminal nerve and combining this with the knowledge of pathological conditions is key to accurate radiological diagnosis at different levels along the course of the nerve. Page 62 of 63

63 References Becker M, Kohler R, Vargas MI, Viallon M, Delavelle J. Pathology of the trigeminal nerve.neuroimaging Clin N Am May;18(2): , x. doi: /j.nic Bathla G, Hegde AN.The trigeminal nerve: an illustrated review of its imaging anatomy and pathology. Clin Radiol Feb;68(2): MacNally SP, Rutherford SA, Ramsden RT, Evans DG, King AT. Trigeminal schwannomas. Br J Neurosurg Dec;22(6): Lakshmi M, Glastonbury CM.Imaging of the cerebellopontine angle. Neuroimaging Clin N Am Aug;19(3): Majoie CB, Verbeeten B Jr, Dol JA, Peeters FL. Trigeminal neuropathy: evaluation with MR imaging. Radiographics Jul;15(4): Page 63 of 63