Ophthalmic Multimedia Systems. Technology and Digital Retinal Imaging: A Changing Dynamic In Eye Care. Digital Imaging Technologies

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1 1 Technology and Digital Retinal Imaging: A Changing Dynamic In Eye Care University of Milan Spring 2007 Anthony Cavallerano, O.D. VA Boston Health Care System The New England College of Optometry Boston Massachusetts anthony.cavallerano@va.gov Ophthalmic Multimedia Systems Optos Retinal Laser Scanner (Optomap) Laser Diagnostic Technology Confocal Laser Scanning Ophthalmoscope and Field Portable Digital Ophthalmoscope Heidelberg Retinal Tomograph Laser Diagnostic Technology Nidek Welch Allyn Carolina Ophthalmics Zeiss Fundus Camera Visucam Ophthalmic Multimedia Systems Digital Imaging Technologies Optical Coherence Tomograph Olympus Corporation Fundus Camera Kowa Co Ltd Fundus Camera Canon Fundus Camera Topcon Instruments of America Non-mydriatic Fundus Camera Krebs Ophthalmic Instruments Bausch and Lomb

2 2 Factors Influencing Purchase and Selection of Technology Mode of practice Composition of practice Ancillary personnel Costs Accessibility of technology and networking capabilities Clinical and Technical Challenges of Telemedicine Programs Installation and training Manufacturer/Technological deployment Commitment for future technology upgrades Storing, archiving and retrieving images Quality assurance and continuing education Validated systems Clinical and Technical Challenges of Telemedicine Programs Digital Imaging Standards Professional acceptance Patient acceptance Billing/clinical coding Standards Compliance: DICOM -Digital Imaging and Communication in Medicine HIPAA Licensure Reimbursement Legal issues DICOM Health Level 7

3 3 DICOM HEALTH LEVEL 7 (HL7) Digital Imaging and Communications in Medicine Standard for transmitting images from your gateway to a server Initiated by Radiology jointly with NEMA (National Electrical Manufacturers Association). Summary: It is a system to identify discreet objects (images) associated with a nomenclature (patient ID) and a dictionary pathway (dependent on system usually an order in an electronic medical record) in a standardized language format (HL7) An ANSI standard for healthcare specific data exchange between computer applications Standardizes the language of healthcare transmission of information and data Data passes through DICOM gateway before HL7 language can be applied and images can show up on a network Digital Imaging and Communication in Medicine The recognized STANDARD for communication of images and related information Voluntary International in scope What is DICOM? Applicable to all imaging including radiographs and photographs. Covers images and attributes Began in radiology and spreading to other specialties Digital Imaging Technologies Digital Fundus Photography Optos P200 Scanning Laser Ophthalmoscope Optical Coherence Tomography (OCT) Heidelberg Retina Tomography (HRT) GDx VCC Drs. Dunphy and Asefzadeh hold no proprietary or financial interest in any of the above technologies

4 4 Digital Fundus Photography Validation Non-mydriatic (NMDRI) NM-2 F4 F6 Screening Mydriatic Documentation F3 F2 F1 Monitoring NM-3 Post-image processing Diagnostic Patient education NM-1 F5 F7 Nonmydriatic Digital Retinal Imaging NMDRI: Diabetic Fields retinal hemes 45-degree, four field, non simultaneous, digital retinal imaging OU (stereo central image) Blurred disc margins Central Superotemporal Temporal Nasal *NMDRI taken in primary care clinic

5 5 Diabetic Retinopathy NMDRI Choroidal Nevus Cotton Wool Spots NMDRI Optic Disc Drusen exudate Epiretinal Membrane Midperipheral Drusen CRVO CRVO pseudohole Current Telemedicine Applications Telemedicine Opportunities Anesthesia Audiology Cardiology Critical care Dermatology Oncology Psychiatry Radiology Patient access Quality of care Cost-effectiveness Disease management Education modules Professional Patient Community Research Opportunities Eye Care

6 6 Clinical Models Glaucoma stereopsis is an important requirement optic nerve head cupping cup to disc asymmetry NFL examination using red-free viewing Age-Related Macular Degeneration Diabetic Retinopathy Nonmydriatic Digital Retinal Imaging Digital retinal does not replace a comprehensive eye examination. 82 YO WM IDDM NON-MYDRIATIC IMAGING IN PRIMARY CARE CLINIC

7 7 56 YO LM H/O IDDM x 15 YEAR 59 YO WM LEE 5 YEARS AGO H/O NIDDM x 10 yrs

8 8 68 YO WM Macular Degeneration: Right Eye Midperipheral drusen Epiretinal Membrane

9 9 Optic disc drusen Cotton Wool Spots Central Retinal Vein Occlusion OD Central Retinal Vein Occlusion OD

10 10 Clinical Application of Digital Retinal Fundus Imaging Patient Education Retinal Blood Vessels Screening of patients at risk for: Diabetes Glaucoma Age related macular disease Vision loss from other disorders/anomalies Interval exams on certain patients within your practice Photodocumentation Patient education! Normal Retina Macula Optic Nerve Challenges of Digital Imaging Technology Image Capture--Quality Image Transmission--Costs Image Reading--Standardization Image Storage--Costs Image Reading Synchronous vs. Store/Forward vs. Real-Time Updating of technology Challenges of Digital Imaging Technology Advantages: Efficient No dilation Can screen in ambulatory care or other settings Disadvantages: Limited field of view Pupil size Image Quality/Artifacts

11 11 NMDRI Artifacts Mydriatic Digital Fundus Photography Post-image Processing Color Red PRP Venous Tortuosity CNVM Green Equalize Histogram HRVO Pupil Size (HRVO) Mydriatic Digital Fundus Photography Post-image Processing Color Equalize Histogram Mydriatic Digital Fundus Photography Post-image Processing Zoomed Color Zoomed Equalize Histogram Equalize Histo Reassigns gray and color values evenly across the spectrum thereby increasing contrast Red-free Equalize Histogram

12 12 Optos Panoramic 200 Case Study: CSDME Minimum 2 mm pupil Green and red coherent light (less scatter) 200º field of view 2000 x 2000 pixels v2 Review Software Images to PC Baseline Type 2 DM and HTN x 20 years Hb A1c 6.7 VA 20/20 OD and OS Amsler/color vision WNL Color 13/14 OU IOP 11 OU Mild NPDR PLAN: RTC 4 mos, r/o CSDME 4 month f/u VA 20/20+ OD and OS Amsler waviness OD superotemporal Clinical suspicion CSDME OU PLAN: Retinal imaging r/o CSDME? FA OS Optomap Color

13 13 Optos Panoramic 200 Red and Green lasers Virtual point inside eye 200 degree field 2000 x 2000 pixels Images to PC environment

14 14 OS Optomap Color OS Optomap Green Channel Optos P200 Advantages Widefield imaging Directs examination focus Red Channel Blue laser capability for UWFFA Green Channel info for RNFL

15 15 Focal NTG Optomap: Field of View intraretinal heme with exudate ring 45º fundus photo Pre-retinal Hemorrhage Optomap: Field of View A Operculated Retinal Hole Optomap: Longitudinal Monitoring B S/P Laser Photocoagulation PRP scars 45º fundus photo C Long-term F/U Zoomed view PRP scars Extension of heme

16 16 Standard View Optomap Post-image Processing: Zoom CRA Zoomed View Vascular Tortuosity CRA Diabetic Macular Edema Vitreous Floater Drance heme Optomap Post-Image Processing: Channels Optos: Post-Image Processing Color Channel Color Channel Red Channel choroid CWS DME CWS DME Large C/D Large C/D Diabetic Retinopathy with DME Green Channel retina Diabetic Retinopathy with DME 45º fundus photo 45º fundus photo

17 17 Optos: Post-Image Processing C/D asymmetry OD>OS, RNFL asymmetry Optos: Post-Image Processing Drance Heme: NTG R Optomap: RNFL dropout 45º fundus photos Robust RNFL Drance heme Optos P200 Optical Coherence Tomography Advantages Widefield imaging plus Zoom capability Red Channel / Green Channel Blue laser capability for UWFFA Green Channel info for RNFL Disadvantages Learning curve for image interpretation Subjective intuitive interpretation StratusOCT TM : >10 µm Ultra High Resolution OCT (UHR-OCT TM ): >5 µm Ultra High Speed Spectral Domain OCT (SD-OCT TM )

18 18 OCT: PRINCIPLES - analogous to ultrasound, BUT uses light (820 nm) instead of sound 2-D scan Pseudocolor scale OCT: PRINCIPLES Light beam sent to the eye and a reference mirror simultaneously The light penetrates through the ocular tissue layers and is reflected back red-white: high reflectivity (RPE and RNFL) blue-green: low reflectivity (ganglion cells, photoreceptors, choroid) black: very low reflectivity (vitreous) cross-sectional image of the underlying tissue The returning light is compared to the reference (interferometry) - Simultaneous array of adjacent A scans comprises a B-scan ILM NFL OCT: Retinal Layers GCL IPL OPL 1. MACULA OCT: Clinical Applications Cross-sections of pathology: qualitative Retinal thickness Analysis: quantitative Visualization of vitreoretinal interface 2. OPTIC NERVE HEAD IS/OS RPE/CC Choroid Optic nerve head diameter Neuroretinal rim area Cup diameter and area Horizontal and vertical ratios between cup and ONH ILM: Inner Limiting Membrane NFL: Nerve Fiber Layer GCL: Ganglion Cell Layer IPL: Inner Plexiform Layer OPL: Outer Plexiform IS/OS: Junction of inner and outer photoreceptor segments RPE: Retinal Pigment Epithelium CC: Choriocapillaris 3. RETINAL NERVE FIBER LAYER Macula Peripapillary

19 19 OCT: Clinical Applications OCT Clinical Applications: Macula Qualitative: - Morphology Concavity vs. convexity Loss of foveal depression Irregularities of retinal surface Changes in intraretinal profile - Reflectivity High: horizontal structures, ERM, CWS, hemes, hard exudates, RPE hyperplasia, drusen, RPE atrophy, CNVM, retinal scars, choroidal nevi Low: vertical structures, fluid, cysts or cavities, shadowed areas, beneath a detachment (RD or PED) Quantitative: -Thickness -Volume - Area Line Scan Single radial line Macular Analysis Six 6mm radial line scans 30º view Diabetic Macular Edema Diabetic Macular Edema 63 y.o. w.m. OS: 20/30 68 y.o.w.m. OS: 20/200

20 20 Cystoid Macular Edema: evolution over time Epiretinal Membrane 50 y.o.w..m.. observe 3/9/06: VA 20/50-2 4/11/06: VA 20/30 1/31/06: VA 20/30+2 2/3/06: VA 20/25 2/28/06 VA: 20/20 Vitreofoveal Traction Syndrome Macular Hole 78 y.o w.m. OD: 20/60 76 y.o.w.m. OS: 20/ y.o.w..m. OD: 20/60- Fellow eye (OD) OD: 20/40+2

21 21 Macular Hole Drusen Age-related Macular Degeneration 59 y.o.w.m. OS: 20/300 Geographic Atrophy Fellow eye OD: 20/20 General Pathologies of Note General Pathologies of Note Exudate Intraretinal Hemorrhage Vitreous Hemorrhage

22 22 Artifacts OCT Clinical Applications: Optic Nerve Head Deficient scan acquisition Misidentification of retinal surfaces by the computer software LOOK AT ANATOMY Optic Nerve Head Scan Six 4mm radial line scans Cross-sectional image of ONH Area of disk, rim, cup Vertical and horizontal C/D Subtraction of hyper-reflective layer Addition of hyper-reflective layer O S Peripapillary RNFL Thickness 1.73 mm radius 3 scans Glaucoma OCT: Optic Nerve Head Analysis Digital Fundus Photography: POAG Patient T Color Green Disc diameter Area of cup, optic disc and optic rim C/D ratio (H & V)

23 23 OCT: Retinal Nerve Fiber Layer Thickness RNFL Thickness Average OU Healthy RNFL Glaucomatous RNFL Patient T RNFL Patient T RNFL Thickness Average OU RNFL Thickness Average OU Patient W notch notch 7/12/06 10/17/06 RNFL Serial Analysis 9/15/05 10/17/06 HVF: Superior arcuate OD, OS

24 24 Non-glaucomatous RNFL Thinning ONH Drusen OCT: Pros/Cons OD Pros Cons Branch Retinal Artery Occlusion OS -Easy -Fast -Reliable -Reproducible - Accurate -Non-contact -Miosis - Media Opacity - Tear Film - Fixation - Spatial Limits Additional Considerations HRT Retina Module Imaging OCT is a tool designed to aid the clinician in the diagnostic process OCT cannot be used in isolation to make clinical decisions HRT II and HRT 3 Beware of artifacts EXAMINE ANATOMICAL SCANS ON EACH PATIENT

25 25 Retinal Surface Measurement Z z z 14 z21 22 z z31 z 32 z41 y Confocal Intensity (Z) Profiles: Normal and Edema 384 x ILM scans y vitreous retina z x intensity z Edema Map Reflectance z 11 z 12 z 13 z 14 z 21 z 22 z 23 Edema Map z 31 z 32 z 41 Width With permission: Flanagan, J. and Hudson, C.

26 26 HRT Scan Reflectance intensity vs.tissue depth Darker pixels indicate less reflectance OS HRT II Reflectance Normal Retina reflectance Topography Vertical Contour z z 14 z21 z 22 z 23 z31 z 32 z41 Low Reflectance High scatter Topography Horizontal Contour OS HRT II Edema Map OPTOS HRT Reflectance FA Normal Retina Value 1.0 AU OCT Lighter values more scatter Horizontal Lighter values more scatter HRT Reflectance

27 27 HRT Retina Module Color PED RED Validated in CSDME Possibly more sensitive than FCLB Monitors change over time Regional information and relationships Highlights H/Ma s and clinical edema No mydriasis required Early FA Late FA Hudson C, Flanagan J et al BJO 1998;82: Kisilevsky, Hudson, Flanagan et al Arch Oph 2006;124: OPTOS PED OS RED FREE

28 28 Optos Stereo Composite Optos Stereo Green Channel Optos Red Channel

29 HRT TOPOGRAPHY 29

30 30 OS RF /200 OS FA 1-06 OS FA OS FA 1-06

31 31 S0370 ICSC /20 no symptoms 49 yo man, c/o spot in OS VA x 1 week GAD Owns own business 20/20 20/40 Initial retinal eval wrinkled surface OS Initial 20/40 OS Optomap Stereo

32 32 HRT II Movie Frame OS Initial Presentation OS ONH / Macula Scan Acute CSCR Increased backscatter papillomacular bundle Low reflectance subretinal space

33 33 OS 1 Month F/U P200 Green OS 1 Month F/U 3-06 Altered reflectance OS HRT II One Month F/U OS HRT II 1 month F/U Edema Map INITIAL

34 34 OCT INITIAL Central Serous Chorioretinopathy Therapy OCT FOLLOW UP 45% recurrence rate Observe 4-6 months Permanent chg in fellow eye, require incr VA Reduces duration 23 wks => 5weeks Green, 6-12 burns, µ, 0.1 s, mW Laser to site of FA leakage Complications: CNVM, scotoma Avoid 200µ from fovea, larger spot size P0805 OS Edema - Iridocyclitis Case Study Iridocyclitis 73-year old male POHx Recurrent uveitis Nongranulomatous anterior uveitis x wks PMHx Type 2 DM last HbA1c 6.4 HTN RA with + HLA-B27

35 35 HRT II Retina Module Features / /30 Reliable validated technology Topographic Information Intraretinal information Regional information

36 36 Zeiss Meditec GDX - VCC Scanning Laser Polarimetry Retardation of polarized light (780 nm) Form birefringence due to arrangement of parallel structures, each of smaller diameter than incident light (microtubules) Polarized light passing through undergoes phase shift (retardation) Polarized light passing through a birefringent medium: splits into two rays ray traveling perpendicular to fibers undergoes a phase shift the shifted ray "slows down" (retardation) Scanning Laser Polarimetry Detector measures retardation between phase shifted ray and unshifted ray Amount of retardation is proportional to the thickness of the nerve fiber layer Validated in two monkey eyes (no K s) Correlated with Red Free photos Weinreb et al.,arch Ophthal,1990 (108)557-60: Morgan J BJO, 1998 (82) : Reus N Oph, (8)

37 37 GDX Strengths / Limitations Compact, Fast, Easy Cataract minimally interferes (820) Variable compensator enhances reliability Unilateral internal fixation PPA interferes with results Anomalous Bundle Pattern Longitudinal Reflectance Thickness Map Deviation Map TSNIT Map

38 ANOMALOUS BUNDLE PATTERN 38

39 GDx VCC

40 40 OS Serial VF OS

41 41 OS Topography OS MRA OS Topography Reflectance

42 42 OS Topography False Color HRT and Glaucoma HRT 3 and Glaucoma Quantitative topographic information Active analysis of rim tissue contour Active analysis of rim density Active analysis of laminar contour Nerve fiber information fixed plane Discrimination and change detection Hardware updates Software Updates Probability analysis Change detection

43 43 ONH / RNFL Model Normal vs. Glaucoma Comparison Normal ONH Glaucomatous ONH Normal GPS -> 9% Glaucoma GPS -> 99% Differences displayed by: GPS values (global and by sector) Image classification by sector Bar graph representation Improved Progression Analysis Topographic Change Analysis (TCA) Improved mathematics to compute significance marker maps Shows gradient (light to dark) to indicate volume and area of significant change Reduces over-sensitivity and false positive rate Cluster Analysis Quantitative and graphical analysis of regions with significant change Magnitude of change displayed as a color gradient Darker red indicates more change Cluster Analysis Lighter red indicates less change

44 44 Application of HRT II in Glaucoma Management Cross sectional vs. Longitudinal evaluation Rim configuration Cup contour Rim relationships RNFL Parameters relative to disc contour Change over time of parameters Relate to clinical findings