B-Scan Ultrasonography

Guide: Dr. S. S. KubreDr. S. S. Kubre

Presented by:Dr. Samreen ArifDr. Samreen ArifRSO- Ophthalmology RSO- Ophthalmology Gandhi Medical College.Gandhi Medical College.

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Introduction :

Ultrasonography of the eye is an indespensible tool in the diagnosis and management of various ocular and orbital abnormalities

It was first used in ophthalmology in 1956 by Mundt and Hughes as A scan

Baum and Greenwood introduced first Bscan in 1958 and first commercially available B-scan was developed Coulmn et al in the seventies

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Physics : Ultrasound is an acoustic wave that

consists of oscillations of particles within a medium, the waves have frequency greater than 20khz(20,000 oscillations/sec)

Diagnostic ophthalmology utilizes frequency of 8-10Mhz (1Mhz=1,000,000cycles/sec)

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Basic elements of ultrasound Pulser Transducer Receiver Display

Modes of display A scan or amplitude modulation scan B scan or brightness modulation scan Vector A scan Three dimensional ultrasound tomography

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Electric Electric

CurrentCurrentLead Zirconate-Lead Zirconate-

titanate titanate CrystalCrystal

Multiple Short Multiple Short Pulse with Pulse with

brief interval brief interval between between

themthem

Longitudinal Longitudinal Ultrasound Ultrasound

WaveWavePropogated Propogated through through mediummedium

Displayed Displayed on on ScreenScreen

Tissue Tissue Ultrasound Ultrasound InteractionInteraction

• Reflection• Refraction• Scattering• Absorption

TransducTransducerer

EchoesEchoes

ProducedProduced

ElectricalElectrical

SignalsSignals

ReceiverReceiver

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A-Scan /Amplitude Modulation ScanA-Scan /Amplitude Modulation Scan It is a one dimensional acoustic display

Modes of displayModes of display

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B-Scan / Brightness Modulation ScanB-Scan / Brightness Modulation Scan

It provides a real time, two dimensional, grey scale display of the eye and the orbit, where different echodensities are depicted in gradations of brightness

Echoes are represented as dots and there strength as brightness of dots on the screen

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Vector A Scan:Vector A Scan: It is the combination of both A Scan

and B Scan

Three dimensional ultrasound tomography:Three dimensional ultrasound tomography: It utilizes ultrasound technique and

digital computer technology where ocular pathology can be viewed in three dimension

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Low frequency:

Useful in detecting orbital pathology Moderate frequency:(7-10MHZ)

Useful in globe examination High frequency:(30-50MHZ)

Useful for imaging anterior segment

Penetration depth of 5 -10mm Immersion technique:10MHZ

Useful for evaluation of anterior chamber

Uses sceleral shell filled with methyl cellulose

Modes of B-scan

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Screening technique

It is best to begin with maximum gain on B scan

Eye is anesthesized with topical paracaine if transducer is kept on sclera

Alternatively eye need not to be anesthesized if probe is kept on close eyelid

Probe is placed on the globe opposite to the area examined

Marker on the probe act as the orientation point

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Techniques used for Evaluation

Transverse techniqueTransverse technique Horizontal transverse:Evaluate superior and inferior

fundus and marker is kept towards nose Vertical transverse:Evaluate the nasal and temporal

fundus and marker is kept towards 12 o’clock Oblique transverse:Evaluate the pathology not

located at major meridians (3,6,9,12 o’clock)

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Axial techniqueAxial technique Horizontal: marker towards the nose Vertical: marker towards 12o’clock position

Techniques used for Evaluation

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Techniques used for Evaluation

Longitudinal techniqueLongitudinal technique Evaluate single meridian from its most

posterior aspect to far periphery Once the cross sectional examination is

completed area of interest is scanned by longitudinal scan

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INDICATIONS

Anterior SegmentAnterior Segmenta. Opaque ocular mediaa. Opaque ocular media

• Pupillary membranePupillary membrane

• Dislocation/subluxation of lensDislocation/subluxation of lens

• Cataract/after cataractCataract/after cataract

• Posterior capsular tear in traumatic Posterior capsular tear in traumatic

cataractcataract

• Pupillary size/reactionPupillary size/reaction

b. Clear ocular mediab. Clear ocular media

• In diagnosis of suspected iris and ciliary In diagnosis of suspected iris and ciliary

body tumoursbody tumours

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Posterior SegmentPosterior Segment

a. Opaque ocular mediaa. Opaque ocular media• Viterous haemorrhageViterous haemorrhage• Viterous exudationViterous exudation• Retinal detachment (type/extent)Retinal detachment (type/extent)• Posterior viterous detachment (extent)Posterior viterous detachment (extent)• IOFB (size/site/type)IOFB (size/site/type)

b. Clear ocular mediab. Clear ocular media• Tumour (size/site/post treatment follow Tumour (size/site/post treatment follow

up)up)• Retinal detachment (solid/exudative)Retinal detachment (solid/exudative)• Optic disc anomaliesOptic disc anomalies

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BiometryBiometry Preoperative scanning and calculation of IOL powerPreoperative scanning and calculation of IOL power

Orbital ExaminationOrbital Examination

ExophthalmosExophthalmos Motility disturbances/diplopiaMotility disturbances/diplopia Palpable orbital massPalpable orbital mass Optic disc oedema and atrophyOptic disc oedema and atrophy Syndromes (superior orbital fissure/orbital apex)Syndromes (superior orbital fissure/orbital apex)

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NORMAL EYE ON B-SCAN

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NORMAL EYE ON B-scanB-scan

It reveals two ecographic areas seperated by an echo It reveals two ecographic areas seperated by an echo

free areafree area

Echographic area at the beginning represent Echographic area at the beginning represent

reverberation at the tip of probe and has no clinical reverberation at the tip of probe and has no clinical

significancesignificance

On high resolution scan posterior convex surface of lens On high resolution scan posterior convex surface of lens

can be seencan be seen

Large echo free area represent viterous cavityLarge echo free area represent viterous cavity Vitero retinal interface forms a smooth curved Vitero retinal interface forms a smooth curved

curvature. Echoes from retina, choroid and scelera curvature. Echoes from retina, choroid and scelera merge merge

Scleral fat boundry is well seen acousticallyScleral fat boundry is well seen acoustically Orbital fat is seen as highly refractile mass with the Orbital fat is seen as highly refractile mass with the

extra ocular muscles forming outline of the fatextra ocular muscles forming outline of the fat Optic nerve seen as triangular shadow within orbital fatOptic nerve seen as triangular shadow within orbital fat To visualize ora serrata ,multiple scan with probe placed To visualize ora serrata ,multiple scan with probe placed

meridonally to bypass lens should be donemeridonally to bypass lens should be done

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Viterous haemorrhageBscan: seen as small white echoes

Fresh and diffuse heamorrhage:little echo response Location:within PVD,pre and post hyaloid Extent Associated fibrous changes

Ascan: low amplitude spikes

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Endophthalmitis B-scan:

Multiple small echogenic opacities with distinct after movements,in severe cases membrane formation .

Associated findings:choroidal thickening,choroidal detachment,retinal detachment,retained IOFB

A-scan: chain of low amplitude spikes

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Retinal tear

B-scan: appear as breach of tissue

A-scan: highly refractile tissue seperated from other fundus spikes

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Retinal detachment

B-scan :B-scan : Recent : bright continuos,somewhat folded Recent : bright continuos,somewhat folded

appearance,mobile retina and translucent subretinal appearance,mobile retina and translucent subretinal spacespace

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Retinal detachment

B-scan :B-scan : Proliferative viteroretinopathy: limited viterous Proliferative viteroretinopathy: limited viterous

space,decreased mobility of retina,funnel space,decreased mobility of retina,funnel shaped(open or close) configuration of shaped(open or close) configuration of detached retina. In triangular RD the sides of detached retina. In triangular RD the sides of triangle represent highly detached stiff retina triangle represent highly detached stiff retina and base is the proliferating viterous and base is the proliferating viterous membranemembrane

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Retinal detachment

Longstanding RD may develop retinal cyst Longstanding RD may develop retinal cyst and become partially calcified and subretinal and become partially calcified and subretinal space filled with cholestrol debrisspace filled with cholestrol debris

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Retinal detachment

Traction retinal detachment:Traction retinal detachment:

Viteroretinal traction bands: focal/broadViteroretinal traction bands: focal/broad Concave configuration of detached retinaConcave configuration of detached retina

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Retinal detachment

Exudative retinal detachment:Exudative retinal detachment: Configuration of the detachment is convex and Configuration of the detachment is convex and

bullousbullous

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Retinoschisis

Bscan :smooth thin dome shaped membrane that does not insert on optic disc

Ascan : 100% high spike is produced

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Posterior viterous detachment Bscan:

undulating membrane in front of retina showing movement with movement of eye and brightness is reduced with reduction of gain

Ascan: tall spikes

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Choroidal detachmentB-scan :B-scan : Smooth, dome shaped membranous structure that Smooth, dome shaped membranous structure that

does not insert on optic nervedoes not insert on optic nerve May be localised or involve entire fundus(kissing May be localised or involve entire fundus(kissing

choroidal detachment)choroidal detachment)

A-scan :A-scan : 100% reflective ,double peaked spikes(retina and 100% reflective ,double peaked spikes(retina and

choroid)choroid)

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Intraocular foreign body Metallic foreign body:Metallic foreign body: very bright signals

that persist on lowering gain, shadowing artefact can be seen on adjacent orbit

Non metallic foreign body:Non metallic foreign body: more challenging, produce bright signals

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Dislocated lens

Round or oval globular structure in posterior viterous and strand of viterous may be attached to dislocated lens

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Posterior globe rupture

Breach of sceleral and choroidal tissue with associated choroidal thickeninig

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Optic nerve avulsion Acute injury: actual peripapillary sceleral

break , viterous haemorrhage may be present

Longstanding cases: proliferative tissue at optic disc

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Retinoblastoma Bscan: large irregular ecogenic mass involving

viterous, retina or the subretinal space with area of calcification seen as area of high ecogenicity

Axial length is either normal or increased Ascan: high internal reflectivity due to areas of

calcification

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Choroidal naevus Localized flat or slightly elevated lesion with

high internal acoustic reflectivity; a low internal reflectivity on A scan is suggestive of malignancy

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Osseous choriostoma Highly reflective anterior surface with

orbital shadowing

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Choroidal melanoma Acoustic hollowness, choroidal excavation and

orbital shadowing

Collar stud configuration is almost pathogonomic (when tumour breakthrough the bruchs membrane)

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Choroidal haemangioma Acoustically solid lesion with the sharp

anterior surface and high internal reflectivity but without choroidal excavation and orbital shadowing

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Metastatic choroidal carcinoma Appear diffuse, typical bumpy and irregular

contour with central elevation A scan: irregular spikes of medium to high

amplitude

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Asteroid hyalosis B-scan:bright round signals showing movement B-scan:bright round signals showing movement

with movement of eye with eco free space just with movement of eye with eco free space just in front of retinain front of retina

Ascan:medium amplitude spikesAscan:medium amplitude spikes

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Cysticercosis

B-scan : Sharply outlined oval cyst within viterous cavity or Sharply outlined oval cyst within viterous cavity or

in the subretinal spacein the subretinal space Scolex seen as highly reflective ecodense nodule Scolex seen as highly reflective ecodense nodule

located adjacent to inner wall of cystlocated adjacent to inner wall of cyst

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Posterior sceleritis Sceleral thickening, sceleral nodules,

fluid in the tenon space give rise to “T sign”

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Phthisis bulbi Smaller globe with multiple ecogenic

viterous opacities,choroidal thickening, calcification of ocular coats with resultant absence of high reflective orbital ecospikes due to shadowing

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Atrophic bulbi

Normal globe contour with normal axial length and calcification of ocular coats

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Choroidal coloboma Excavation of posterior pole with sharp

edges Associated features: microphthalmos and

retinal detachment

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Posterior staphyloma Shallow excavation of posterior pole with

smooth edges in highly myopic eyes

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Optic nerve drusen Calcified nodules that produces echoes of

high reflectivity at or within optic nervr head

Best seen by transverse and longitudinal approach that bypass lens

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Immersion technique

Iris melanoma

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High resolution B scan

Ciliary body detachment Large cleft seen in subciliary space

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High resolution B scan

Iris melanoma

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Artefacts: Insufficient fluid coupling causes

entrapment of fluid between probe and eye leading to bright echoes

IOL may act as foreign body Tumours: Mass <0.75mm may be missed Viteroretinal disease: In retinal detachment usually the actual

tears may be missed

Shortcomings of B-scan

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Intraocular foreign body IOFB <0.5mm can be missed Reflectivity of wooden foreign body can be

decreased with time Orbit Orbital mass cannot be differntiated or

detected if <3mm in size in anterior and <5mm in size in posterior orbit

Biometery Wrong axial length may be obtained if probe

does not aligned with optical axis,indentation of cornea,fluid meniscus in front of cornea

Shortcomings of B-scan

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Recent surgery Open globe injury Active infection of ocular surface HIV infection

Contraindications of B-scan

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