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A Closer Look Into Optic Nerve Gliomas


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A Closer Look Into Optic Nerve Gliomas

  1. 1. A CLOSER LOOK INTO OPTIC NERVE GLIOMAS A Presentation By Jamie Annand and Angela Brasz
  2. 2. OPTIC NERVE GLIOMA <ul><li>What is it? </li></ul><ul><ul><li>Low-grade astrocytoma of the optic nerve </li></ul></ul><ul><ul><li>Prevalence in both adults and children </li></ul></ul><ul><ul><li>May be situated anteriorly or posteriorly in the optic nerve </li></ul></ul><ul><li>Childhood ONG </li></ul><ul><ul><li>Roughly 5% of all childhood brain tumours </li></ul></ul><ul><ul><li>Age of onset: 6 months to 10 years </li></ul></ul><ul><li>Adult ONG </li></ul><ul><ul><li>Very rare version of adult </li></ul></ul><ul><ul><li>astrocytoma </li></ul></ul><ul><ul><li>Age of onset: 22 years to 79 years </li></ul></ul>
  3. 3. ADULT AND CHILD PATHOLOGY <ul><li>Tumour more commonly malignant </li></ul><ul><li>Infiltrates hypothalamus and temporal lobe </li></ul><ul><li>Prognosis is poor </li></ul><ul><li>Treatment has not been shown to prolong life </li></ul><ul><li>Tumour usually benign </li></ul><ul><li>Does not tend to metastasize </li></ul><ul><li>Prognosis is good </li></ul><ul><li>Growth patterns unpredictable </li></ul><ul><li>Difficult to determine treatment </li></ul><ul><li>Adult Form of ONG </li></ul><ul><li>Child Form of ONG </li></ul>
  4. 4. NEUROFIBROMATOSIS-1 (NF-1) <ul><li>Autosomal dominant genetic disorder </li></ul><ul><li>Probably some combination of genetic and environmental factors </li></ul><ul><li>ONG may occur with or without the presence of NF-1 </li></ul><ul><ul><li>Patients with NF-1 do not necessarily develop ONG </li></ul></ul><ul><li>ONG with NF-1 is indicative of a better prognosis </li></ul>
  5. 5. A STUDY <ul><li>Study by Kornreich, 2001 </li></ul><ul><li>Hospitals involved: Sick Children Hospital in Canada and the Schneider Children’s Medical Center of Israel </li></ul><ul><li>All known to have optic nerve gliomas. Those not presenting symptoms were biopsied to confirm diagnosis </li></ul><ul><li>Assessments were performed using both Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) </li></ul><ul><li>All patients with progressive tumour signs underwent chemotherapy treatment </li></ul>
  6. 6. STUDY INVOLVING THE PRESENCE AND ABSENCE OF NF-1 IN ONG <ul><li>10-38% with NF-1 develop ONG </li></ul><ul><li>Symptoms present 32% of time </li></ul><ul><li>Most common site of involvement: Orbital Nerve (66% of patients) </li></ul><ul><li>Tumour in general smaller </li></ul><ul><li>Original shape of optic nerve maintained </li></ul><ul><li>Symptoms present 100% of time </li></ul><ul><li>Most common site of involvement: Chiasm and Hypothalamus (91% of patients) </li></ul><ul><li>Maximal diameter and volume of tumour significantly greater </li></ul><ul><li>Tumour was mass-like with extension beyond optic pathways </li></ul><ul><li>Optic Nerve Glioma With NF-1 </li></ul><ul><li>Optic Nerve Glioma Without NF-1 </li></ul>
  7. 7. SIGNS AND SYMPTOMS OF CHILDHOOD OPTIC NERVE GLIOMA <ul><li>The most common sign of ONG is progressive loss of vision </li></ul><ul><li>Other major symptoms include: </li></ul><ul><ul><li>Changes in visual acuity </li></ul></ul><ul><ul><li>Proptosis may occur in later stages </li></ul></ul><ul><ul><li>Involuntary eye movements </li></ul></ul><ul><ul><li>Changes in appetite and sleep </li></ul></ul><ul><ul><li>Neurologic deficits </li></ul></ul><ul><ul><ul><li>Nausea, headache and vomiting </li></ul></ul></ul><ul><ul><ul><li>Caused by obstructive hydrocephalus </li></ul></ul></ul><ul><li>Rarely, childhood Optic Nerve Glioma can result in death </li></ul>
  8. 8. IMAGING OPTIC NERVE GLIOMAS <ul><li>RADIOGRAPHY </li></ul><ul><ul><li>Plain films used </li></ul></ul><ul><ul><li>Orbits imaged </li></ul></ul><ul><li>ANGIOGRAPHY </li></ul><ul><ul><li>Not currently used </li></ul></ul><ul><ul><li>Examined blood vessels around the orbit </li></ul></ul><ul><li>COMPUTED TOMOGRAPHY </li></ul><ul><ul><li>Great soft tissue definition </li></ul></ul><ul><ul><li>Also visualizes bony detail </li></ul></ul><ul><li>MAGNETIC RESONANCE IMAGING </li></ul><ul><ul><li>Currently GOLD STANDARD in tumor imaging </li></ul></ul><ul><ul><li>Superior contrast resolution of soft tissue structures </li></ul></ul>
  9. 9. WHY COMPUTED TOMOGRAPHY? <ul><li>Often used for diagnosis and elimination of differential diagnosis </li></ul><ul><li>Can detect subtle erosions or expansions of optic canal indicative of optic nerve glioma </li></ul><ul><li>Has the option of reformatting images to better visualize pathology </li></ul><ul><li>Can use several algorithms which mathematically change the contrast </li></ul><ul><li>and brightness settings </li></ul>(Auntminnie, 2008)
  10. 10. WHAT'S SO GREAT ABOUT MAGNETIC RESONANCE IMAGING? <ul><li>Currently the Gold Standard in optic nerve glioma imaging </li></ul><ul><li>Superior nervous tissue differentiation </li></ul><ul><ul><li>Allows for better visualization of </li></ul></ul><ul><ul><li>subtle lesions </li></ul></ul><ul><li>Best for visualizing nerves </li></ul><ul><li>and nerve pathways </li></ul><ul><li>No Dose </li></ul>(Auntminnie, 2008) Axial Protocol Contrast Gadolinium Scan Type Axial Scanning Area Midlevel of maxillary sinuses to mid-portion of frontal sinuses Slice Thickness 3-5mm Spacing 1-2mm In-Plane Resolution 256 x 192 or 256 x 256 Coronal Protocol Contrast Gadolinium Scan Type Coronal Scanning Area Posterior globe through cavernous sinus to posterior aspect of brain stem Slice Thickness 3-5mm Spacing 1-2mm In-Plane Resolution 256 x 192 or 256 x 256
  11. 11. A COMPARISON <ul><li>Inferior contrast resolution to MRI </li></ul><ul><li>Better with calcifications and bony detail than MRI </li></ul><ul><li>High amounts of dose </li></ul><ul><li>Large availability </li></ul><ul><li>Shorter scan times </li></ul><ul><li>Less expensive </li></ul><ul><li>Superior contrast resolution to CT </li></ul><ul><li>Subtle changes in the optic nerve better visualized with MRI </li></ul><ul><li>No dose </li></ul><ul><li>Availability limited </li></ul><ul><li>Longer scan times </li></ul><ul><li>More expensive </li></ul><ul><li>Computed Tomography </li></ul><ul><li>Magnetic Resonance Imaging </li></ul>
  12. 12. FUTURE IMPLICATIONS OF IMAGING <ul><li>PET-CT SCAN </li></ul><ul><ul><li>Helpful in staging of the disease </li></ul></ul><ul><ul><li>Effectively locates the tumour which is useful for treatment </li></ul></ul><ul><ul><li>Can assess tumour progression/recession following treatment </li></ul></ul><ul><ul><li>Allows the possibility for a less invasive technique that could easily replace more invasive ones </li></ul></ul><ul><li>PET-MRI SCAN </li></ul><ul><ul><li>Same application as a PET-CT scanner </li></ul></ul><ul><ul><li>Better soft tissue than CT </li></ul></ul><ul><ul><li>More expensive </li></ul></ul>
  13. 13. MORE IMPLICATIONS OF FUTURE IMAGING <ul><li>MAGNETIC RESONANCE SPECTROSCOPY (MRS) </li></ul><ul><ul><li>MRI with non-invasive characterization of tissue </li></ul></ul><ul><ul><li>spectroscopic patterns of gliomas different than normal brain tissue </li></ul></ul><ul><ul><li>potentially help in delineating tumour spread </li></ul></ul><ul><li>VISUAL EVOKED POTENTIALS (VEPs) </li></ul><ul><ul><li>uses electroencephalography to evaluate conduction of visual pathway from optic nerve through optic chiasm to occipital cortex </li></ul></ul><ul><ul><li>useful in detecting anterior visual pathway disturbance </li></ul></ul><ul><ul><li>Findings indicate that results may not be reliable for children under 5 years old (peak age for ONG) </li></ul></ul>
  14. 14. TREATING OPTIC NERVE GLIOMA’S <ul><li>Goal of Treatment: </li></ul><ul><ul><li>To halt the progression in vision loss or tumour growth </li></ul></ul><ul><li>Types of treatment include: surgery, chemotherapy and radiation therapy </li></ul><ul><li>Treatment is started when imaging studies show continuous tumor progression or vision deterioration </li></ul><ul><li>Treatment will rarely restore vision loss, but is very successful in decreasing the tumor size or stopping its growth </li></ul><ul><li>After treatment patient should be monitored for further vision loss and the effect of treatment </li></ul>
  15. 15. RADIATION THERAPY <ul><li>Preferred method for children over 6 years of age 15 years ago </li></ul><ul><li>Major side effects of cranial irradiation: </li></ul><ul><ul><li>Mental retardation </li></ul></ul><ul><ul><li>Endocrinopathies </li></ul></ul><ul><ul><li>Cerebrovascular disease </li></ul></ul><ul><li>Fortunately side effects are less common today due to treatments that are more precisely focused on abnormal tissue </li></ul>
  16. 16. CHEMOTHERAPY <ul><li>First line treatment 15 years ago in patients under 6 years of age or younger </li></ul><ul><li>In the last 10 years chemotherapy has now been determined as the best form of treatment for all ages </li></ul><ul><li>Due To: </li></ul><ul><ul><li>Toxicity of Radiation Therapy for all age groups </li></ul></ul><ul><li>If Chemotherapy fails, </li></ul><ul><li>radiation therapy is then used </li></ul>
  17. 17. A COMPARISON <ul><li>Side effects can be more serious </li></ul><ul><li>High dose to patient </li></ul><ul><li>Should only be used if chemotherapy not effective </li></ul><ul><li>Most common side effect is nausea </li></ul><ul><li>No radiation dose </li></ul><ul><li>Should be used initially </li></ul><ul><li>Radiation Therapy </li></ul><ul><li>Chemotherapy </li></ul>
  18. 18. FUTURE IMPLICATIONS FOR TREATMENT <ul><li>By far the most controversial issue related to ONG </li></ul><ul><li>FRACTIONATED STEREOTACTIC RADIOTHERAPY </li></ul><ul><ul><li>A more controlled beam of radiation is used </li></ul></ul><ul><ul><li>Prevents increased dose to nearby tissue </li></ul></ul><ul><ul><li>CT SIM is used to plan procedure </li></ul></ul><ul><li>GAMMA KNIFE </li></ul><ul><ul><li>highly focused x-ray beams make up a “knife” which “cuts” through diseased tissue </li></ul></ul><ul><ul><li>Allows for more precisely targeted tumour tissue that may be located deeper in the brain </li></ul></ul><ul><ul><li>Recovery time is shorter and the procedure itself is painless </li></ul></ul>
  19. 19. CONCLUSION <ul><li>Optic nerve gliomas are a common primary brain tumour in children </li></ul><ul><li>Although they are seen as mostly benign and slow growing, there is increasing concern in the treatment of these tumours </li></ul><ul><li>It is now believed that the tumour should be treated directly when vision loss or notable progression of the tumour becomes apparent </li></ul><ul><li>New imaging and treatment options can be used to help with earlier detection, more accurate treatment planning and better prognosis </li></ul>
  20. 20. THANK YOU FOR YOUR ATTENTION! <ul><li>References </li></ul><ul><li>Agamanoliz, D.P. (n.d.). Neuropathology. Retrieved March 13, 2008, from . </li></ul><ul><li>Anonymous. (2004). Apache Server. March 13, 2008, from </li></ul><ul><li>Anonymous. (2008). GE Medcyclopaedia. March 13, 2008, from . </li></ul><ul><li>Anonymous. (2005). Scanners to give research boost. March 13, 2008, from   </li></ul><ul><li>Auntminnie Case of the Day. (2008) Childhood Optic Nerve Glioma. Retrieved from: .   </li></ul><ul><li>Carlson, A.H. (2007). Siemens Demonstrates Prototype MRI-PET System. March 13, 2008, from </li></ul><ul><li>Gujar, S., Maheshwari, S., Bjorkman-Burtscher, I. & Sundgren, P. (2005) Magnetic resonance spectroscopy. Journal of Neuro-opthalmology, 25 (3), 217-226.  </li></ul><ul><li>Hollander, M.D., Fitzpatrick, M., O’Connor, S.G., Flanders, A.E., Tartaglino, L.M. (1999). Optic Gliomas. Imaging in Ophthalmology, 37 (1), 59-71. </li></ul><ul><li>Huszar, L. (2006) Clinical Utility of Evoked Potentials. Retrieved from: .   </li></ul><ul><li>Kansas, S. (n.d.). Salina Regional Health Center. March 13, 2008, from . </li></ul><ul><li>Kornreich, L., Blaser, S., Schwarz, M., Shuper, A., Vishne, T.H., Cohen, I.J., Faingold, R., Michovitz, S., Koplewitz, B., Horev, G. (2001). Optic pathway glioma: correlation of imaging findings with the presence of neurofibromatosis. American Journal of Neuroradiology, 22 , 1963-1969. </li></ul><ul><li>Listernick, R., Louis, D., Packer, R. & Gutmann, D. (1997) Optic Pathway Gliomas in Children with Neurofibromatosis 1: Consensus Statement from the NF1 Optic Pathway Glioma Task Force . Annals of Neurology , 41 (2), 143-149. </li></ul><ul><li>Liu, G.T. (2006). Optic gliomas of the anterior visual pathway. Current opinion in ophthalmology, 17 , 427-431. </li></ul><ul><li>Martin, N.A. (2007). UCLA Neurosurgery. March 13, 2008, from </li></ul><ul><li>Shuper, A., Horev, G., Kornreich, L., Michowiz, S., Weitz, R., Zaizov, R., Cohen, I.J. (1997). Visual pathway glioma: an erratic tumour with therapeutic dilemmas. Archives of disease in childhood, 76 , 529-263. </li></ul><ul><li>Woodcock, R. (2007) Optic Nerve Glioma. Retrieved from: . </li></ul>