Nw2015 rcopt oct_retina22
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Transcript of Nw2015 rcopt oct_retina22
Interpreting OCTs in
Common Macular Diseases
Nawat Watanachai
RCOPT : July 2015
1
» pros of FDOCT
– accurate
– reproducible
– non invasive
– fast
» good in
– diagnosis
– gold std in some diseases
– monitor objectively
– retinal thickness measurement
– fluid collection
why OCT
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How to get the best information
from macular OCT?
» 1. do the RIGHT scan
» 2. read the scan properly
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How to get the best information
from macular OCT?
» 1. do the RIGHT scan
» take the best image
» minimise all possible
error» 2. read the scan properly
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Image
Acquisition
1. centralization
– pts c good vision : easy
– Pts c poor fixation : hard
• Identify the fovea location
• Place the scan on it correctly5
Image Acquisition2. Data verification and validation
– Do it at the end of scanning session
– error in the retinal boundary delineation
– re-do the scan
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Image Acquisition
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2. Data verification and validation– Verify centralizationof the 6 scans– Retinal map(single eye), retinal
thickness/volume (OU) analyze protocols»SD should be around 0 mcm»SD > 30 mcm
» poor centration » do the scan again
Image acquisition3. raster scanning
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• radial
OCT Basic Knowledge :
Scan Patterns for macula
• raster
• cruciate • single
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OCT Basic Knowledge :
radial line protocol
– 6X 6mm-long lines, 30’ apart
– Center at foveal center
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3. raster scanning– to minimize the chance of missing morphological
details
– 8 mm length scan
– best for vitreomacular adhesion
– May hit small lesions that missed on radial protocol
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OCT Basic Knowledge :
raster scan protocol
Image acquisition
A. foveal split B. lamellar hole
A’ FTMH B’ FTMH
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OCT Basic Knowledge :
Retinal thickness map
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color Thickness (microns)
White >470
red 350-470
Orange 320-350
Yellow 270-320
Green 210-270
blue 150-210
» from radial scan
Retinal Thickness
» 1. fundamental of OCT automatic retinal thickness
measurement
– algorithm (math. calculation)
– presumes 2 high reflective structures
• 1. VR surface
• 2. RPE-photoreceptor outer segment interface
– compares the shape of 1 a-scan to adjacent a-scans 14
OCT Basic Knowledge :
Retinal thickness map
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» Depth 2 mm
» For thickness map
» Interpolation for thickness between sample point
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Retinal Thickness
machine can be error
» 2. software delineation of outer neuro-sensory retinal boundary
» HRL
– TDOCT : RPE-choriocapillaries reflective complex
– SDOCT : 2 lines
• IS/OS junction
• RPE-choriocapillaries reflective complex
Retinal Thickness
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» 2. software delineation of outer neuro-
sensory retinal boundary
» SDOCT sometimes detect innerHRL as
outer boundary of retina
• error in thickness measurement
• may need manual caliper-assisted
technique
– auto VS manual differed by 9.9-38%
• Costa 2004
Retinal Thickness
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Retinal Thickness
» (L) automated retinal thickness measurement (VR-IS/OS)
» (R) manual retinal thickness measurement
» difference 51 mcm
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Image acquisition
4. scan review software tool
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How to get the best information
from macular OCT?» 1. do the RIGHT scan
» 2. read the scan properly
» systematic approach
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Basic Principles in OCT reading
» Know your retinal histo/histopathology
» Know what is normal : contour/ thickness
» Remember you’re dealing with
» light and its wave properties
» Reflections/ interfaces
» Attenuation/ shadowing
» Always consider image quality/ artefacts
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OCT Basic Knowledge :
Retinal layers in OCT
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»High reflectivity : NFL/ IS-OS Junction/ RPE-choriocapillaris»Intermediate reflectivity : plexiform layers»Low reflectivity : nuclear layers/ photoreceptor outer segment/ vitreous»Fovea
»Absence of inner retinal layer»Increased thickness of the photoreceptor layer 24
OCT Basic Knowledge :
Retinal layers in OCT
»High reflectivity : NFL/ RPE/ choriocapillatis
»Intermediate reflectivity : plexiform layers»Low reflectivity : nuclear layers/ photoreceptor outer segment/ vitreous
»Fovea
»Absence of inner retinal layer
»Increased thickness of the photoreceptor layer25
OCT Basic Knowledge :
Retinal layers in OCT
»High reflectivity : NFL/ RPE/ choriocapillatis
»Intermediate reflectivity : plexiform layers
»Low reflectivity : nuclear layers/ photoreceptor outer segment/ vitreous»Fovea
»Absence of inner retinal layer
»Increased thickness of the photoreceptor layer26
OCT Basic Knowledge :
Retinal layers in OCT
• defining inner and outer HRL
• HRL - Highly Reflective Layer
• TD OCT : single line
• FD OCT : 2 lines 27
OCT Basic Knowledge :
Retinal layers in OCT
• defining inner and outer HRL
• FD OCT : not 1 line, but 2
• inner line : IS/OS junction
• outer line : RPE choriocapillaris complex
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OCT Basic Knowledge :
Retinal layers in OCT
» IS/OS junction
» correlated with VA
» irregularities at the level of inner HRL after MH Sx prevent VA improvement
» Uemoto 2002, Kitaya 2004, Villate 2005.29
OCT Basic Knowledge :
Retinal layers in OCT
IS/OS junction : correlated with VA
RP
localization of missing photoreceptor
component
Jacobson 1998, 2000
cone-rod dystrophy, Best macular dystrophy
prediction of subret./ subRPE deposits
Aleman 2002, Pianta203
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OCT Basic Knowledge :
Retinal layers in OCT
OCT Basic Knowledge :
Retinal layers in OCT
shadows
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Let’s read
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Morphologic assessment
» 1. determine scan quality
» 2. rate overall scan profile
» 3. evaluate foveal profile
» 4. identify foveal cut
» 5. structural assessment33
Morphologic assessment
» 1. determine scan quality» 2. rate overall acan profile
» 3. evaluate foveal profile
» 4. identify foveal cut
» 5. structural assessment
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» 1. determine scan quality
» identify inner and outer retinal boundaries
» good signal to noise ratio
» rescan?
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Morphologic assessment
» 1. determine scan quality
» 2. rate overall scan profile» 3. evaluate foveal profile
» 4. identify foveal cut
» 5. structural assessment36
» 2. rate overall scan profile
» normal over-all retinal profile
» slightly concave curvature
» abnormal
» exaggerated concavity and
convexity or retinal folds
» watch for artefact
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» 1. retinal detachment
» RRD/ TRD/ ERD/ HRD
» 2. retinal thickening
» CSME/ CME/ CNV
» 3. RPED
» fibrous/ serous/ hemorrhage
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» 2. rate overall scan profile
Morphologic assessment
» 1. determine scan quality
» 2. rate overall scan profile
» 3. evaluate foveal profile» 4. identify foveal cut
» 5. structural assessment
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» 3. evaluate foveal profile
» normal foveal profile
» slightly depression in the surface of
retina
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Morphologic assessment
loss of foveal depression
some problems
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» 3. evaluate foveal profile
» deformations in the foveal profile
» VR surface
» ERM/ pseudohole
» MH/ Lamellar hole/ macular cyst
» Retina
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Morphologic assessment
» 1. determine scan quality
» 2. rate overall acan profile
» 3. evaluate foveal profile
» 4. identify foveal cut» 5. structural assessment
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» 4. identify foveal cut
» do we need rescan?
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back to
Image
Acquisition
1. centralization
• Identify the fovea location
• Place the scan on it correctly
– Centre line tool(OCT3 software) : right
click45
Morphologic assessment
» 1. determine scan quality
» 2. rate overall acan profile
» 3. evaluate foveal profile
» 4. identify foveal cut
» 5. structural assessment
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Morphologic assessment
» 5. structured assesment» alteration of layers
» Systematic : antpost
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» 5. structured assesment : Preretinal/ Epiretinal
preretinal-vitreous cavity
syneresis/ VH
Epiretina
ERM/ MH
vitreo-retinal strands
vitreo-retinal traction
NVE
NVD
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»5. structured assesment : Preretinal/ Epiretinal
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»5. structured assesment : Preretinal/ Epiretinal
» Vitreous assessment
» Search for opacities eg
» posterior hyaloid
» MH operculum51
»5. structured assesment : Preretinal/ Epiretinal
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»5. structured assesment : Preretinal/ Epiretinal
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» consider looking for ERM/ PVD
traction in difficult DME cases
»5. structured assesment : Preretinal/ Epiretinal
DME: high prevalence of perifoveal PVD
Gaucher 2005
favorable macular remodeling in DME
after spontaneous PVD
Watanabe 2000, Yamagachi 2003
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»5. structured assesment : Preretinal/ Epiretinal
A,B : PVD
C : VM traction
D. remodel after completion of PVD
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»5. structured assesment : Preretinal/ Epiretinal
» Look for areas of abnormal VMT
» Identified areas where thin hyperreflective band from the vit insert into the retina
» Look for ERM
» Thin hyperreflective structures which show multiple areas of attachment and separation from the inner retinal surface
» may demonstrate free posterior hyaloid face
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»5. structured assesment : Preretinal/ Epiretinal
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»5. structured assesment : Preretinal/ Epiretinal
VMT
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»5. structured assesment : Preretinal/ Epiretinal
ERM
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»5. structured assesment : Preretinal/ Epiretinal
ERM
» early MH
» oblique vitreofoveal tractional forces
» intrafoveal split
» Hee1995, Gaudric1999,
Haouchine2001, Tornambe2003 60
»5. structured assesment : Preretinal/ Epiretinal
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»5. structured assesment :
Preretinal/ Epiretinal
» early MH
» late MH
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»5. structured assesment
: Preretinal/ Epiretinal
» FTMH: typical configuration
» round cystic margins
» SRF
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»5. structured assesment : Preretinal/ Epiretinal
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»5. structured
assesment :
Preretinal/
Epiretinal
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» 5. structured assesment: Intra-Retinal
1. macula edema
diffuse
cystoid
2. hard exudates
3. scar tissue
4. atrophic degeneration
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» macula edema : Characteristics
» diffuse vs cystoid
» Central/symmetric vs asymmetric (eg RVO)
» Remember thickened retina can attenuate
signal
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» 5. structured assesment: Intra-Retinal
» Cystic space : Discrete area of
hyporeflectivity
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» 5. structured assesment: Intra-Retinal
Case courtesy of Dr. Scott Lee, East Bay Retina Consultants, Oakland, CA, USA
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» 5. structured assesment: Intra-Retinal
Mid-retina slab enface view emphasizes the presence of hard exudates in a subject with mild macular
edema
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» 5. structured assesment: Intra-Retinal
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» 5. structured assesment: Intra-Retinal
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» 5. structured assesment: Intra-Retinal
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» 5. structured
assesment:
» Intra-Retinal
» Retinal thinning
» Increase transmission of light to the deeper layer
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» 5. structured assesment: Intra-Retinal
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» 5. structured assesment: Intra-Retinal
» Retinal thinning
» mostly found in late stage of many
diseases
IS/OS-Ellipsoid Enface Slab: Hydroxychloroquine toxicity example with classic bull’s eye
maculopathy
Case courtesy of Dr. Scott Lee, East Bay Retina Consultants, Oakland, CA, USA
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» 5. structured assesment: Intra-Retinal
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» 5. structured assesment: Intra-Retinal
thick/ thin/ edema
» 1. CNV
» 2. RPED
» 3. drusen
» 4. subretinal fibrosis
» 5. scar
» 6. RPE atrophy
» 7. SRF
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» 5. structured assesment: sub-retina
» Separation between neural retina and RPE
» Generally hyporeflective
» Look for associated RPE level change eg
small PED in CSR
» Partial preservation of foveal depression
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» 5. structured assesment: sub-retina
clear SRF
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» 5. structured assesment: sub-retina
» Not hyporeflective space
» Presence of tissue eg typeII CNV,
subretinal fibrosis
» Hemorrhage or lipid
» Viscous SRF eg fibrinous CSR
» Correlate with color fundus photo/ FA/
ICG***
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» 5. structured assesment: sub-retina
NOT so clear SRF?
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» 5. structured assesment: sub-retina
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» 5. structured assesment: sub-retina
A. 1st visit
B. 6 wks after
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» 5. structured assesment: sub-retina
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- drusen
- RPED
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» 5. structured assesment: RPE/ sub-RPE
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» 5. structured assesment: RPE/ sub-RPE
drusenSmall/ discrete low-lying areas of RPE elevation
c highly reflectivity
» RPED : area of hypo-reflectivity
underneath RPE elevation
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» 5. structured assesment: RPE/ sub-RPE
» RPED
» Assess its size, contour and reflectivity
» Look for adjacent areas
» eg atrophy from RPE tear
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» 5. structured assesment: RPE/ sub-RPE
Morphologic assessment : RPE elevation
» RPED : content
» serous/ hemorrhagic/ fibrovascular
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some samples
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1021
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2. 1 yr later after rx
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3
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the end