A quick guide to Ophthalmic Ultrasound/ B-Scan interpretation
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This document is a comprehensive guide to ophthalmic ultrasound and B-scan interpretation, providing detailed terminology, principles, and techniques for evaluating various ocular conditions. It covers ultrasound frequency ranges, indications for scans in both ocular and orbital assessments, normal appearances, and descriptions of lesions. The guide also includes information on different ocular pathologies, their ultrasound characteristics, and distinctions between similar conditions.
![Ocular scans
• Probe positions
• Transverse : on sclera (@ TS)
• Longitudinal :at Limbus (@ LL)
• Axial : on cornea (@ AC)
• [NOTE: Markers aims nasally while screening superior &
Inferior and Superiorly for nasal & temporal]](https://image.slidesharecdn.com/ophthalmicultrasound1-200512132749/85/A-quick-guide-to-Ophthalmic-Ultrasound-B-Scan-interpretation-10-320.jpg)
A quick guide to Ophthalmic Ultrasound/ B-Scan interpretation
- 1. A quick guide to Ophthalmic Ultrasound / B-Scan Interpretation Amit K Singh Consultant optometrist Mechi Eye Hospital ,Birtamode-3 Jhapa
- 3. Terminology • Audible Range : 10-20,000 Hz • Ultrasound : > 20,000 Hz • Pulse echo system: piezoelectric transducer to generate ultrasonic wave, a receiver which processes returning waves and a display screen • Acoustic impedance: Difference b/w strength of returning echoes from tissue boundaries • Angle of incidence: angle of sound beam relative to area of interest
- 4. Terminology(contd) • Resolution: ability to distinguish b/w adjacent echoes, both axial & lateral • Amplification: signal processing before echoes is displayed on monitor • Gain: procedure of increasing or decreasing amplitude of echoes that are displayed on screen • Time gain compensation(TGC) : technique used to enhance returning echoes from deeper structures by reducing those from structures closer to surface
- 5. Principle of B-scan Electrical energy sound energy electronic energy (Display) • Abdominal ultrasound : 1-2 MHz • Ophthalmic Ultrasound : 8-12 MHz • Ultrasound Biomicroscopy : 35-100 MHz • Frequency α 1/penetration α Resolution PiezoelectricPiezoelectric
- 6. Indications of ocular B-scan • Opaque media 1. Corneal opacity 2. A/c hyphema or hypopyon 3. Miosis 4. pupillary membrane 5. Cataract 6. Vitreous haemorrhage
- 7. • Clear media 1. Iris lesion 2. ciliary body lesion 3. Tumours & masses;detection & differentiation 4. RD :Rhegmatogenous vs exudative 5. IOFB detection and localization 6. OD abnormalities
- 8. Indications of orbital B-scan • Enophthalmos • Globe displacement • Lid abnormalities • Palpable or visible mass • Chemosis • Motility disturbance • Pain
- 9. Technique of Evaluation • Clinical correlation
- 10. Ocular scans • Probe positions • Transverse : on sclera (@ TS) • Longitudinal :at Limbus (@ LL) • Axial : on cornea (@ AC) • [NOTE: Markers aims nasally while screening superior & Inferior and Superiorly for nasal & temporal]
- 11. Normal appearance of ocular & orbital Structures 1. Lens • Immersion/ stand off technique • None to highly reflective intralesional echoes depending on amount of cataract 2. Vitreous : Echo free , low to medium ref. In vitreous degeneration. 3. Retina, choroid & sclera : seen as single until/unless pathological conditions e.g. RD,CD, scleritis 4. Optic Nerve: Wedge shaped acoustic void in retrobulbar region Vitreous Optic Nerve
- 12. Orbital Scans • Probe placement 1. Transocular : lesions of mid & posterior orbit i.e. structures within muscular cone (Opposite side ) 2. Paraocular : lesions of lids & anterior orbit i.e. structures beyond muscular cone (same side) Transocular Scan Paraocular Scan
- 13. Extraocular Muscles(EOM) • EOM are best evaluated by transverse & longitudinal scans. • Echolucent to low reflective fusiform str. • SR-LPS complex : Thickest • IR : Thinnest • IO : Not imaged except in pathological conditions
- 14. Description of a Lesion • Location w.r.to easily demonstrable landmarks e.g. optic disc or lens in an intraocular lesions • Extent : both antero-posterior & lateral • Dimensions: in cases of tumours and other solid lesions • Shape & configuration : point like , membrane like or a mass • Internal reflectivity : Echolucent ,low , moderate or high. Sclera has 100% reflectivity • Structure : solid or cystic, regular or irregular • Mobility : active movements and after movements
- 16. Reverberation Artifacts Dropped IOL Si oil Reverberation PCIOL Reverberation Artifact d/t Insufficient Coupling
- 17. Shadowing • Shadowing: d/t Ca,glass,bone ,air metal ,gas Shadowing
- 18. Angle of incidence artifact Right Eye Left Eye Left Eye High reflective lesion (arrowhead) Shifting of lesion s/o artifact •Angle of incidence artifact : probe is perpendicular to surface •Often mistaken with IOFB, scar
- 19. Vitreous Hemorrhage Low gain High gain
- 20. Subhyaloid hemorrhage Increases echoes in inferior quadrant PVD
- 22. Vitreous Hemorrhage with Retinal tear Retinal Tear(Arrow) VH
- 24. Vitreous hemorrhage with hemorrhagic PED VH Hemorrhagic PED
- 25. Retinal Breaks & Detachment Rhegmatogenous Tractional Exudative Convex elevation Concave elevation Convex elevation Tractional Band Shifting of fluid with postural change /by pressing with finger Supine position Erect position Open funnel shaped RD
- 26. RRD with PVR PVR Open funnel shaped RD
- 27. Closed funnel shaped RD with cyst formation Cyst Closed funnel shaped RD Cyst
- 28. RRD with Giant retinal tear GRT
- 29. RD Vs. PVD •Restricted Aftermovement in kinetic scan •High reflective membrane @ ONH • Membrane thickness remains const. in minimal tilt of probe •Membrane visible at low gain RD •Free Aftermovement in kinetic scan •High reflective membrane may or may not @ ONH •Variable thickness in membrane in minimal tilt of probe •Membrane disappear at low gain PVD
- 30. Hemorrhagic choroidal detachment (Expulsive) Kissing choroid with suprachoroidal hemorrhage
- 31. Retinoschisis Vs.Exudative RD/PED Vs. Choroidal Detachment (CD) Retinoschisis Exudative RD Choroidal Detachment Kissing choroidal sign ‘M’ spike Dome shaped appearance Shifting of fluid with postural change /by pressing with finger No change in fluid / structure by pressing with finger Supine Erect100% single picked spike seen just anterior Retina 100% single spike
- 33. Intraocular Foreign Body IOFB inside lens IOFB @ Retinal surface IOFB within Optic Nerve IOFB within anterior vitreous
- 35. Endophthalmitis Vs. VKH syndrome VKH SYNDROME ENDOPHTHALMITIS •U/L •H/o Sx, Trauma •PVD may or may not present and develop TRD •Vitreous cells •B/L •Serous RD • No PVD •Few vitreous opacities
- 36. Panophthalmitis Vs Posterior Scleritis PANOPHTHALMITIS POSTERIOR SCLERITIS Marked thickening of the Ocular coats & low reflective infiltration in Tenon’s capsule in Panophthalmitis ‘T’-sign
- 37. Ocular Cysticercosis Vs Dislocated Lens Scolex Lens Nucleus In supine position Both seem to be same but in erect position dislocated lens moves inferiorly The live cyst does not cause inflammatory sign
- 39. Choroidal Melanoma Vs. Choroidal Hemangioma Acoustic Hollowing Choroidal Melanoma Choroidal Hemangioma
- 40. ONH Melanocytoma High reflective mass over ONH
- 41. Choroidal Melanoma Vs. Choroidal Metastases CHOROIDAL MELANOMA CHOROIDAL METASTASES Regular Contour Irregular contour
- 43. Choroidal Osteoma Vs Phthisis Bulbi Double Optic Nerve like appearance Plaque like calcification Coats Calcification
- 45. Coloboma of the Choroid & Optic Disc Detached ICM(Thick Arrow) Large optic disc coloboma Chorio -retinal coloboma Scleral fistula (Thick arrow) Small break (thin arrow)Detached ICM(Thin Arrow)
- 46. Choroidal Coloboma Vs Posterior Staphyloma Posterior Staphyloma Choroidal Coloboma Smooth margin Sharp margin
- 48. PFV Vs. Vitreous incarceration(VI) Vs. ROP PFV/ PHPV ROP VI
- 50. Silicon Oil Elongated eyeball •Do USG in all quadrants • Never forget inferior & superior quadrant to comment
- 51. Emulsified Si oil (ESO) Vs. Asteroid Hyalosis(AH) Vs. Vitreous Hemorrhage(VH) Vs. Vitreous Cells(VC) ESO AH VH VC
- 52. Scleral Buckle High surface reflectivity with orbital shadowing
- 53. Scleral Buckle Vs. Scleral folds Thickening of RC complex (Arrowhead) Scleral folds(Arrow) Scleral Buckle(Arrowhead) Scleral folds & Scleral buckles,esp. scleral sponges have similar appearance on ultrasound .But in case of folds hypotony present .
- 54. Intraocular Air Vs PCIOL IOL reverberationIntra ocular air reverberation Spherical shadows floats opposite to the direction of eye movement in Intraocular air/gas
- 56. Optic Nerve Thickening •Normal diameter of retrobulbar optic nerve : 2.2 – 3.3 mm •Difference : ˃0.5 mm b/w two nerves is of significance •30˚ test : r/o Tumour from Pseudotumour Gross thickness Thickness deceases Pseudotumour Doughnut /Crescent sign
- 57. Papilleodema Doughnut /Crescent sign Disc elevation
- 58. Optic Nerve Glioma Subtle thickening of OD w.r.to OS
- 59. Optic Disc Abnormalities High gain Low gain Optic Disc Drusen
- 60. Gross Cupping Optic Disc cupping •Minimum cup disc ratio of 0.5 is necessary to detect cupping on USG •Medium gain
- 61. Reference • Bhende M et al .(2013). Atlas of Ophthalmic Ultrasound and Ultrasound Biomicroscopy. Jaypee Brothers Medical Publishers(P) Ltd, 2nd Edition ,ISBN 978-93-5090-535-7. • Contact :[email protected] • (+977-9819617489)
Editor's Notes
- #17: Reverberation artifacts : d/t insufficient coupling gel b/w eye & probe and due to IOLs & air gun pellets
- #22: Double membrane configuration
- #25: d/t polypoidal choroidal vasculopathy
- #32: shifting fluid changes with postural change
- #46: ICM :The neural retina continues as ICM in the area of the coloboma.
- #49: Persistence of Fetal Vasculature ,Persistent hyperplastic primary vitreous (PHPV),Retinopathy of Prematurity (ROP)
- #57: 30˚ test positive means pseudo thickening