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Unveiling MRI Abnormalities in Neurologic Visual Nuances

This text delves into various neurologic conditions affecting visual function, emphasizing the importance of MRI in diagnosis. It highlights instances where MRI abnormalities were overlooked or misinterpreted in cases such as hypoxic-ischemic encephalopathy, nonketotic hyperglycemia, and optic tract trauma. The dialogue between an examiner and a machine underscores the need for sensitivity and attentiveness in reading MRI signals to avoid missing crucial neurological findings.

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Unveiling MRI Abnormalities in Neurologic Visual Nuances

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  1. Neurologic Visual Nuances Jonathan D. Trobe, MD Professor of Ophthalmology and Neurology University of Michigan

  2. EXAMINER: “DON”T LET ME DOWN. I DEPEND ON YOU!”

  3. MACHINE: “YOU ASK TOO MUCH OF ME.”

  4. YOU DO NOT EXPECT MRI TO BE ABNORMAL* • Toxic optic neuropathy • Nutritional optic neuropathy • Infiltrative (cancerous) optic neuropathy • Indirect optic nerve trauma *At least acutely! Thinning (atrophy) and high T2 signal often appear late

  5. EXAMINER: “WHY CAN’T YOU BE MORE SENSITIVE?”

  6. MACHINE: “I CANNOT ALWAYS MEET YOUR VERY HIGH EXPECTATIONS!”

  7. YOU EXPECT MRI TO BE ABNORMAL, BUT IT IS SOMETIMES NORMAL 1. Retrobulbar neuritis 2. Hypoxic-ischemic encephalopathy 3. Nonketotic hyperglycemia

  8. Hypoxic-ischemic encephalopathy • 45 year old man with spontaneous cardiac arrest* • Recovers neurologic function but visual acuities hand movements OU • Eye exam normal *Parmar HA, Trobe JD. J Neuro-Ophthalmol 2016;36:264

  9. Hypoxic-ischemic encephalopathy MRI Five Days After Cardiac Arrest MRI Four Months After Cardiac Arrest, (Visual Acuity Now 20/25 OU) DWI FLAIR FLAIR

  10. Nonketotic Hyperglycemia • 68 year old man changes diabetes medication that leads to very poor control (blood sugar > 600 mg/dL)* • Develops “intermittent photopsias and distorted vision” • Visual acuities 20/50, 20/40; eye exam otherwise normal except… *Taban M, Naugle RI, Lee MS. Arch Ophthalmol 2007;125:845

  11. Nonketotic Hyperglycemia • Neuropsychologic exam normal • MRI and single-photon emission computed tomography (SPECT) normal! • Electroencephalogram not performed • Blood glucose corrected and patient recovers completely within seven days *Taban M, Naugle RI, Lee MS. Arch Ophthalmol 2007;125:845

  12. Nonketotic Hyperglycemia: Another Case With Normal MRI *Freedman KA, Polepalle S. Am J Ophthalmol 2004;137:1122

  13. EXAMINER: “WHY CAN’T YOU BE MORE SENSITIVE?”

  14. MACHINE: “I’M HERE FOR YOU. YOU JUST DON’T READ MY SIGNALS!”

  15. MRI ABNORMALITIES SUBTLE AND OFTEN OVERLOOKED 1. Hypoxic-ischemic encephalopathy 2. Nonketotic hyperglycemia 3. Lateral geniculate body ischemia, vasogenic edema (PRES) 4. Occipital cerebritis 5. Creutzfeldt-Jakob Disease 6. Visual variant Alzheimer Disease

  16. Hypoxic-ischemic encephalopathy: Very Mildly Abnormal MRI Overlooked • 16 year old boy with cardiac arrest in motor vehicle accident* • Resuscitated and recovers neurologic function but says “I can’t see” • Visual acuity 20/15 OU but visual fields *Margolin E et al J Neuro-Ophthalmol 2007;27:292

  17. Hypoxic-ischemic encephalopathy: Very Mildly Abnormal MRI Overlooked MRI 11 Days After Resuscitation: Read as “Normal” FLAIR T2 DWI Margolin E et al. J Neuro-Ophthalmol 2007;27:292

  18. Hypoxic-ischemic encephalopathy: Abnormal MRI Overlooked Visual field loss persists Margolin E et al. J Neuro-Ophthalmol 2007;27;292

  19. Hypoxic-ischemic encephalopathy: Abnormal MRI Overlooked Repeat MRI 60 Days After Resuscitation MRI 11 Days After Resuscitation suscitatiion Margolin E et al J Neuro-Ophthalmol 2007;27:292

  20. Nonketotic Hyperglycemia: Abnormal MRI Misinterpreted • 4 patients with NKH, blurred vision, and temporary homonymous hemianopias* • 2 of 4 no previously known diabetes • EEG showing abnormalities in ALL: slowing in 2, spikes in 2 *Lavin PJM Neurology 2005;65:616

  21. Nonketotic Hyperglycemia: Abnormal MRI Misinterpreted Post-contrast T1 T2 DWI ADC Decreased T2, gyral enhancement, restricted diffusion *Lavin PJM Neurology 2005;65:616

  22. Nonketotic Hyperglycemia: Abnormal MRI Overlooked • MRI interpreted as focal encephalitis, tumor, or migraine • Vision recovers within days of normalizing glucose • Repeat MRIs are normal *Lavin PJM Neurology 2005;65:616

  23. Optic Tract Trauma: Abnormal MRI Overlooked • 45 year old man has closed head injury in motorcycle accident* • Regains consciousness and appears neurologically normal, but claims no sight in left hemifield • Neuro-ophthalmology exam shows left homonymous hemianopia but no pupil or fundic abnormalities • Brain MRI 2 months after accident reported as “normal” so I thought he was malingering! *Kowal KM J Neuro-Ophthalmol 2017;37:17

  24. Optic Tract Trauma: Abnormal MRI Overlooked Kowal KM J Neuro-Ophthalmol 2017;37:17

  25. Where’s the MRI Abnormality? • 20 year old pre-medical student develops high-altitudinal sickness • Emerges from coma and notes poor vision in right hemifield • Visual acuity normal • Right afferent pupil defect • Bowtie disc pallor right, temporal pallor left • Right homonymous hemianopia Grabe H et al. J Neuro-Ophthalmol 2012;32:38

  26. Where’s the MRI Abnormality? MR Contrast Venogram Non-contrast CT CT: lucencies in both thalami (black arrows), blood products at terminus of internal cerebral veins (white arrow) Non-opacification of both internal cerebral veins (arrow)

  27. Where’s the MRI Abnormality? Axial spoiled gradient T1 shows encephalomalacia in region of left lateral geniculate body (arrow)

  28. Lateral Geniculate Body PRES: Really? • 31 year old woman develops binocular blurred vision and headache in 38th week of gestation* • Diagnosed with hemolysis, elevated liver enzymes and low platelets (HELLP syndrome) • Treatment: anti-hypertensive agents and platelet transfusions • Delivered by C-section of healthy baby, but… *Stem M et al. J Neuro-Ophthalmol 2014;34:372

  29. Lateral Geniculate Body PRES: Really? • On 1st post-partum day, vision falls to finger counting OU • Neuro-ophthalmological exam: bullous retinal detachments OU • In 48 hours, vision recovers to 20/25 OU but retinal detachments unchanged Stem M et al. J Neuro-Ophthalmol 2014;34:372

  30. Lateral Geniculate Body PRES: Really? High FLAIR signal in lateral geniculate bodies bilaterally; no signal abnormality in optic radiation or cortex! Stem M et al. J Neuro-Ophthalmol 2014;34:372

  31. Isolated Lateral Geniculate Body Damage: Subtle MRI Abnormalities T1 Post-Contrast FLAIR Post-contrast T1 FLAIR Extrapontine myelinolysis Donahue, Kardon, Thompson AJO 1996;119:378 Shock-induced Lefebvre PR et al. AJNR 2004;25:1544 H1N1 Influenza Breker DA et al J Neuro-Ophthalmol2015;35:265 Idiopathic microinfarct-induced Mudumbai RC. J Neuro-Ophthalmol 2007;27:169

  32. Occipital Cerebritis: Is MRI Abnormal? • 15 year old girl gets headache, lassitude, mild nausea • Complains of blurred vision in inferior right hemifield and seeing “whirling ceiling fan” there • Neuro-ophthalmic exam normal except…

  33. Occipital Cerebritis: Is MRI Abnormal? T2 FLAIR Pre-Contrast T1 Post-Contrast T1 Subtle high FLAIR signal in left occipital region without enhancement

  34. Occipital Cerebritis: Is MRI Abnormal? • Standard blood tests negative • Lumbar puncture normal • Electroencephalogram: slowing in left occipital region • Recovers spontaneously after several months • Follow-up MRI normal

  35. Creutzfeldt-Jakob Disease: MRI Normal At Outset • 66 year old woman reports blurred vision in left inferior hemifield* • Ophthalmologic exam is normal except… • Brain MRI normal! *Prasad S et al J Neuro-Ophthalmol 2010;30:260

  36. Creutzfeldt-Jakob Disease: MRI Normal At Outset • Visual field worsens, “shimmering lights,” “palinopsia”, “impaired depth perception” • Neurologic exam: “mildly-impaired tandem gait, copying” Prasad S et al J Neuro-Ophthalmol 2010;30:260

  37. Creutzfeldt-Jakob Disease: MRI Normal At Outset MRI now shows subtle visual cortex abnormalities Prasad S et al J Neuro-Ophthalmol 2010;30:260

  38. Creutzfeldt-Jakob Disease: MRI Normal At Outset • LP normal (14-3-3 “ambiguous”) • VEP and EEG normal • FDG PET abnormal in parieto-occipital regions Prasad S et al J Neuro-Ophthalmol 2010;30:260

  39. Creutzfeldt-Jakob Disease: MRI Normal At Outset • Patient loses all vision over 8 weeks, develops myoclonus, impaired arousal • Dies within 12 weeks of symptom onset • Autopsy: neuronal loss and spongiform vacuolization MOSTLY OCCIPITAL Prasad S et al J Neuro-Ophthalmol 2010;30:260

  40. “Visual Variant” Alzheimer Disease • 75 year old man has 3 car crashes, all on his right side • His wife reports slight cognitive slowing and short-term memory loss • Hesitant navigation, impaired puzzle-solving • Visual acuity 20/20 OU, otherwise normal ophth exam except…

  41. “Visual Variant” Alzheimer Disease Also described by Brazis P, Lee AG, Graff-Radford N, Desai NP, Eggenberger ER. J Neuro-Ophthalmol 2000;20:92

  42. Conclusions 1. Retrobulbar vision loss may rarely display no MRI abnormalities or very subtle and overlooked abnormalities 2. Every segment of the visual pathway may show this phenomenon

  43. Conclusions MRI Abnormalities May Be Normal or Subtle and Overlooked Retrobulbar neuritis Hypoxic-ischemic encephalopathy Radiation optic neuropathy Optic tract trauma/ischemia Lateral geniculate PRES/ischemia Visual cortex cerebritis Creutzfeldt-Jakob disease Alzheimer disease Nonketotic hyperglycemia not rare not rare not rare rare rare rare rare rare very rare

  44. Conclusions 3. Faced with strong clinical evidence for persistent retrobulbar visual loss: • Review MRI with experts • Get higher-definition MRI with special sequences • Repeat MRI later • Deploy functional imaging: EEG, VEP, fMRI, SPECT, PET

  45. Case 1 • 30 year old woman with clinical features of new retrobulbar neuritis OS • Good quality MRI normal! • Patient elects no treatment; vision recovers completely within weeks 2 months

  46. Case 1 How often is good quality (orbit) MRI normal in acute retrobulbar neuritis?

  47. Case 1: Retrobulbar neuritis • Published sensitivity (thickening, enhancement, high T2) = 94%-97%* • Unpublished U of Michigan study has MRI sensitivity of only 84%! *Kupersmith MJ et al. Brain 2002; 125:812 Hickman SJ et al. J Neurol 2004;251:996 Rizzo JF et al. Ophthalmology 2002;109:1679

  48. Case 2 • 73 year old woman undergoes 30 Gy x-irradiation for metastatic lung cancer to frontal lobe • 10 months later, loses all vision OS over several days • Neuro-ophthalmologic exam shows retrobulbar optic neuropathy without chiasmal features • Neurologic exam otherwise normal • MRI performed 2 weeks after acute vision loss is normal

  49. Case 2 • 2 months later, loses vision OD to finger counting • Small APD OS; normal fundus OD; pale optic disc OS • MRI performed at time of vision loss OD shows RIGHT pre-chiasmatic optic nerve enhancement, but LEFT pre-chiasmatic optic nerve still looks normal

  50. Case 2 • Vision does not change • 17 months after vision loss OS and 15 months after vision loss OD, right optic nerve enhances briskly and left optic nerve now enhances slightly

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