Neuro Imaging ENHANCE YOUR UNDERSTANDING OF NEURO- IMAGING. Optometric Practice 5/11/2015. CT Computed Tomography

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1 ENHANCE YOUR UNDERSTANDING OF NEURO- IMAGING Presented by Kelly A. Malloy, OD June, 2015 Nothing to Disclose Neuro Imaging In Optometric Practice Kelly A. Malloy, OD NOTHING TO DISCLOSE CT Computed Tomography - Good for looking at BONE and BLOOD - (trauma) - Can be helpful to detect nerve sheath meningiomas - Used to R/O fractures, sub-dural, sub-arachnoid H - Different window widths used ( Bone, soft tissue, etc.) - Available in the ER setting - Axial and coronal sections only - NO SAGITTAL sections possible(unless reconstructions) 1

2 CT CONTRAINDICATIONS Radiation exposure pregnant women children CT CONTRAST Iodine based / injected into vein (allergies) Block x-rays from reaching film (density levels) Contraindicated in asthma, DM / kidney probs Check BUN/creatinine levels prior to ordering Necessary for CTA Contrast IS necessary CT Angiography (CTA) View arteries of head (COW) and neck (carotids, vertebrals) Can view as cross section or in 3D Look for aneurysms, AVMs, stenosis 2

3 MRI Magnetic Resonance Imaging Magnetic field / hydrogen atom alignment NO radiation exposure Good for looking at ANATOMY / SOFT TISSUE NOT normally available in the ER setting MRI Imaging Planes Axial, coronal and sagittal sections AXIAL CORONAL SAGITTAL 3

4 MRI Sagittal section Sagittal section useful to view: cervico medullary junction pituitary gland pineal region corpus callosum * SAGITTAL * * * MRI T1 Weighted Images Recovery time (TR) less than 0 msec CSF, vitreous are DARK Good for viewing ANATOMY Used with CONTRAST media Compare T1 with and without contrast (enhance) MRI T2 Weighted Images Recovery time (TR) greater than 0 msec CSF, vitreous are BRIGHT Good for seeing PATHOLOGY(H2O & edema) T1 T2 4

5 Dark Vitreous T1 Bright Vitreous T2 T2 CORONAL THROUGH OCCIPITAL LOBE HELPFUL TO IDENTIFY OCCIPITAL STROKE 5

6 MRI FLAIR (Inversion Recovery) Recovery time is greater than 0 msec Like a T2, but the CSF, vitreous are DARK Better view of pathology, especially in areas adjacent to CSF (ventricles, etc.) - good for looking periventricular white matter changes (in MS, etc) MRI Diffusion Weighted Imaging (DWI) Very fast recovery time (few msec) Used to diagnose ACUTE INFARCTS -Bright area = acute stroke -Be aware of normal areas of artifact -Sensitive to recent changes in vascular perfusion ADC Map Apparent Diffusion Coefficient Apparent Diffusion Coefficient has become an important diagnostic aid to DWI. ADC is the post processing of DWI. ADC maps are usually looked at with more credibility than DW images because there could be T2 shine through on the DW images. T2 shine through means the fluid that would normally be bright on a T2 weighted image could appear bright on a DWI since the DWI is usually T2 weighted. 6

7 On DWI Restricted Diffusion of molecules appears: Bright (More spins stuck in one area = more signal) Normal Diffusion of molecules appears: Dark (Less/No spins = No signal) On ADC map Dark Bright MRI GRADIENT ECHO (GRE) Used to view BLOOD (Hemosiderin) Not regularly done Need to request this sequence if blood is expected Hemosiderin appears dark From: Osbourne, Anne Diagnostic Neuro- Radiology 7

8 From: Osbourne, Anne Diagnostic Neuro-Radiology SWAN Susceptibility weighted MR angiography Uses GRE to acquire images SWAN helps clearly delineate small blood vessels, microbleeds, and large vascular structures in the brain; visualizes iron and calcium deposits. Helps to identify axonal injury in TBI Helps to identify small stroke/hemorrhage GADOLINIUM Contrast media for MRI NOT iodine based Less potential for allergic reaction Contrast needed if suspect a mass, metastasis, abscess, inflammation, infiltration Alters magnetic field (differing signals) Crosses a disturbed blood brain barrier Abnormalities demonstrate areas of enhancement Used to compare pre & post contrast T1 images 8

9 GADOLINIUM Relatively safe However, recently, many facilities require kidney function tests, especially in diabetics or those with possible kidney dysfunction Nephrogenic Systemic Fibrosis Tissue fibrosis in pts with impaired renal fxn that are exposed to gadolinium May need BUN & creatinine tests prior to Gad ORBITAL STUDY Need to specify if orbital study is needed (MR/CT) Obtain thinner cuts through the orbital region Fat is dark in CT (good to view ON, EOMs) If MRI need to do fat suppression Unable to do fat suppression in open gantry Best done in a CLOSED gantry MRA (head / neck) - Contrast NOT necessary - View arteries of head (COW) and neck (carotids, vertebrals) - Image is obtained by flow voids in vessels - Vessels are normally dark due to movement of blood - Series of acquisition images are used - Look for aneurysms, AVMs, stenosis 9

10 MRV Used to view venous sinuses Contrast is NOT necessary Look for venous sinus thrombosis (pts c papilledema / HA) Can be difficult to interpret -? congenital dominance / hypoplasia THE VENOUS SYSTEM 10

11 MR CONTRAINDICATIONS PACEMAKERS COCHLEAR IMPLANTS METALLIC FB IN ORBITS RECENT STENTS, METALLIC IMPLANTS (unless titanium is used) Claustrophobia Weight limitations Previous Allergy to Contrast Medium Medication Patches (must be removed) ORDERING STUDIES Type of study, studies Body part (Brain, orbits, c spine, etc.) Specific sequences requested (if not standard) Areas to direct special attention Clinical findings suggesting localization Release films to patient so they can be re viewed if necessary NEED TO KNOW ANATOMY Where do signs/symptoms localize anatomically Need to know where to direct attention on the study Should be able to determine where to focus the study, and what looking for prior to ordering study 11

12 NEED TO REVIEW FILMS Only you have the clinical history, symptoms, and signs that lead to localization Need to be sure that clinical picture can be explained by radiologic findings.or else you need to look for something else Sometimes need to be able to review films yourself or take them for review with a neuro radiologist CASE 1 91 year-old woman Hx of poor VA OD - ARMD x 7 yrs HTN, diverticulitis s/p cervical CA 28 yrs ago (radiation/chemo) referred for Rt. abduction deficit ASYMPTOMATIC no diplopia, no pain, etc 12

13 VA: OD 20/400 (EF) OS 20/30 Pupils iatrogenically fixed (cat ext) CF: OD central scotoma OS full PA: OD 8mm OS 10mm LF: OD 12mm OS 16mm DFE: geographic atrophy OD OD 85 OS Ductions 40 8LH 40eso 16eso 6eso Distance Neurologic Exam Decreased sensation of CN V1 and V2 on right side as compared to left side 13

14 Localization Right CN V1, V2 Right CN III Right Abduction deficit (CNVI) = Right Cavernous Sinus / Orbital Apex -Neuro-imaging to R/O mass -(?mets /meningioma) CASE 1 14

15 Wall enhancement Flow artifact Suggestive of intracavernous ICA aneurysm Need to further evaluate with an MRA ORDER: MRA of head (Circle of Willis) OD 85 OS 8LH 40 40eso 16eso 6eso RIGHT INTRA-CAVERNOUS ICA ANEURYSM 15

16 CASE 2 CASE 6 69 year old woman Difficulty focusing with OS x 5 months Better VA with closing OS Some discomfort OS x 1 year Sys Hx: (+)HTN x 10 yrs, heart valve replacement Meds: Coumadin, Norvasc, enalapril, vit C, Ca CASE 6 VA: OD 20/25 0S 20/20 Color: OD 7/7 OS 7/7 PERRL ( ) RAPD CF: full OU Palpebral aperture: OD 5mm OS 5mm Exophthalmometry: OD 20mm OS 20 mm Left abduction deficit Slowed saccades Ductions > versions (+) Forced duction 16

17 OD OS 50 6eso25eso 35eso Work Up MRI (brain & orbits) With and without gadolinium Laboratory Testing CBC, ESR, CRP, platelets ACE, ANA, RPR, FTA ABS, Lyme titer AChR antibodies(binding, blocking, modulating) TSH, T4, TSI, Thyroperoxidase Ab, Thyroglobulin Ab ALL REPORTED TO BE NORMAL!! 17

18 Left cavernous sinus enhancement With enhancing tail indicative of meningioma Treatment Monitor for interval change with repeat MRI in 6 months Trial of Fresnel prism Pt reports significant improvement 15 prism diopter BO OS Able to drive Doesn t have to close OS CASE 3 18

19 84 year old woman Previous Dx of ARMD OU EXAM RESULTS VA: OD 1 ft, OS LP PERRL ( + ) APD 1.2 log NDF OS Confrontation fields: central and peripheral loss in each eye, with best vision remaining centrally Ocular motility: intact, no restrictions Ocular heatlth: healthy anterior segment structures, PC IOL OU Posterior pole photos, taken on initial presentation, showing mild macular drusen, not consistent with the level of visual acuity Optic disc photos, taken on initial presentation, showing diffuse neuro-retinal rim pallor bilaterally 19

20 Goldmann bowl perimetry OD, 3 months status-post surgical resection of the tuberculum sellae meningioma (improved from pre-surgical acuity of hand motion) CASE 4 20

21 68 year old woman Diplopia x 3 months Daughters noticed crossed eye x 3 months ( ) other symptoms Sys Hx: Clinical depression, mental health issues ( ) vasculopathic risk factors Exam Results: VA: OD 20/25 OS 20/25 Color: OD 13/14 OS 13/14 PERRL ( )RAPD CF: full Normal neurologic exam Negative Forced Duction Test 21

22 Left Cavernous Sinus Mass Report Indicates Left Cavernous Sinus Meningioma Our review of films indicates flow voids.suggesting ICA aneurysm 22

23 S/P Aneurysm Coiling L CN VI Palsy remains stable - does not appreciate prism CASE 5 23

24 CASE 6 24

25 63 year old man c/o fatigue x 3 wks worst HA of life x 3 days episode of nausea / vomiting Pulsatile tinnitus All symptoms now improving Sys Hx: DM, HTN BCVA: OD 20/30 OS 20/30 Color: 14/14 OD, 14/14 OS PERRL (-) RAPD 25

26 CASE 7 52 YO woman referred for VF defects noted change in VA on 9/11/01 (2 yrs prior to presentation) Went to ER 9/11 told of BP 200/140 Still notes problems with superior VF OU Hx of HTN (23 yrs), heart murmur, hypercholesterolemia Procardia, multivitamins Denies eye or head pain, diplopia Notes 5 episodes of dizziness, transient blur OU 1 episode of L upper & lower extremity numbness x 15 min 26

27 VA: OD 20/20 OS 20/20 Pupils isocoric, ( - )RAPD Color: OD 14/14 OS 14/14 Normal ductions, versions, OKN SLE: xanthalasma OU DFE:.40/.40 cup, NRR intact and pink OU retina normal OU Neurologic Exam: normal 27

28 LOCALIZATION Bilateral Superior Altitudinal VF Defect Normal ONH appearance OU Normal Retinal appearance OU = Inferior Calcarine Bank (Lingula) bilaterally - Neuro-imaging of occipital cortex for infarct ORDERED: MRI of brain T2 coronal sections through occipital lobe Gadolinium contrast NOT necessary MRA of head MRA of neck Special attention to Inferior Calcarine Bank and vertebrobasilar / PCA circulation MRI NORMAL T2 coronals NOT done Axials didn t image the occipital lobes MRA not approved by insurance company RE-ORDER: MRI with T2 coronal sections 28

29 When you see BILATERAL altitudinal defects, in the setting of NORMAL optic nerves and retina Right HH combined with Left HH Localizes to OCCIPITAL LOBE Shared posterior blood supply Likely INFARCT need neuro imaging (be sure occipital region imaged) don t just rely on written report IF YOU ORDER THE STUDY, YOU NEED TO HAVE FILMS REVIEWED! STROKE IN YOUNG REQUIRES WORK UP TO FIND CAUSE urgent referral to stroke neurologist (TIAs) THANK YOU. ANY QUESTIONS? 29