5/11/2015

1

ENHANCE YOUR UNDERSTANDING OF NEURO-IMAGINGPresented by Kelly A. Malloy, ODJune, 2015

Nothing to Disclose

Neuro‐Imaging…

Optometric…In

Kelly A. Malloy, OD

NOTHING TO DISCLOSE

Practice

CT

- 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)

Computed Tomography

5/11/2015

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

CT Angiography  (CTA)

Contrast IS necessary

‐ View arteries of head (COW) and neck  (carotids, vertebrals)

‐ Can view as cross‐section or in 3D  

‐ Look for aneurysms, AVMs, stenosis

www.ctisus.com

5/11/2015

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

5/11/2015

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 1000 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 1000 msec

•CSF, vitreous are BRIGHT

•Good for seeing PATHOLOGY(H2O & edema)

T1

T2

5/11/2015

5

Dark Vitreous

T1

Bright Vitreous

T2

T2 CORONAL THROUGH OCCIPITAL LOBE

HELPFUL TO IDENTIFY OCCIPITAL STROKE

5/11/2015

6

MRI ‐ FLAIR (Inversion Recovery)

• Recovery time is greater than 1000 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 MapApparent 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. 

5/11/2015

7

Restricted Diffusion of molecules appears:

Normal Diffusion of molecules appears:

On DWI Bright (More spins stuck in one area = more signal)

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

5/11/2015

8

From: Osbourne, Anne Diagnostic Neuro-Radiology

SWANSusceptibility‐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

5/11/2015

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

5/11/2015

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 VENOUSSYSTEM

5/11/2015

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

5/11/2015

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

5/11/2015

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 OS

40

100

85

100

100

100

100100

16eso40eso 6eso

8LH

Ductions

CT @ Distance

Neurologic Exam

•Decreased sensation of CN V1 and V2 on right side as compared to left side

5/11/2015

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

5/11/2015

15

•Wall enhancement

•Flow artifact

•Suggestive of intracavernous ICA aneurysm

•Need to further evaluate with an MRA

ORDER: MRA of head (Circle of Willis)

100

16eso40eso 6eso

8LH

RIGHT INTRA-CAVERNOUS ICA ANEURYSM

OD OS

40

100

85

100

100

100

100

5/11/2015

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

5/11/2015

17

25eso 35eso6eso

OD OS

100

100

100

100

100

100

100 50

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 !! 

5/11/2015

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

5/11/2015

19

84 year – old woman Previous Dx of ARMD OU

EXAM RESULTS VA: OD HM @ 1 ft, OS LP PERRL ( + ) APD 1.2 log NDF OS Confrontation fields: central and peripheral loss in eacheye,

with best vision remaining centrally Ocular motility: intact, no restrictions Ocular heatlth: healthy anterior segment structures, PCIOL 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

5/11/2015

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

5/11/2015

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

5/11/2015

22

Left Cavernous Sinus Mass

Report Indicates Left Cavernous Sinus

Meningioma

Our review of films indicates flow voids….suggesting ICA

aneurysm

5/11/2015

23

S/P Aneurysm Coiling

L CN VI Palsy remains stable -does not appreciate prism

CASE 5

5/11/2015

24

CASE 6

5/11/2015

25

• 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

63 year old man

5/11/2015

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

5/11/2015

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

5/11/2015

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

5/11/2015

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)

ANY QUESTIONS?

THANK YOU.