USG / UBM

1. ULTRASONOGRAPHY (USG) AND
ULTRASOUND BIOMICROSCOPY(UBM)
DR.GAURAV SHUKLA
ICARE EYE HOSPITAL, NOIDA

2. INTRODUCTION
 USG of the eye – A very important tool in the diagnosis of ocular &
orbital abnormalities.
 First used in ophthalmology in 1956 by Mundt & Hughes as A scan.
 Baum & Greenwood introduced first B scan in 1958.
 In the sixties, imaging of the eyeball and orbit using ultrasound was
popularized by Ossoinig.

4. PRINCIPLES OF USG
 Ultrasound wave has a frequency more than 20 KHz.
 With increase in frequency, the wavelength decreases.

5.  So USG probes used in ophthalmology have higher
frequency (10MHz) as less tissue penetration is required
& have higher resolution.
 UBM probes use a frequency of 50-100 MHz that
penetrates only 5-10 mm of eye so used mainly for
detailed examination of anterior segment.

6. INSTRUMENT
 An USG unit is composed of :
Pulser
Receiver
Display screen
Transducer
 High freq. sound waves, transmitted by a probe into the eye & strike
intraocular structures & reflected back & converted into an electric
signal & reconstructed as an image on a monitor.

9. PRINCIPLE OF IMAGING IN USG
 Pulse Echo System.
 Probe- an oscillating sound beam is emitted, passing
through the eye.
 The echoes of which are represented as accumulation of
dots that together form an image on the screen.

10. A scan B scan
A- Amplitude B- Brightness
One dimensional Two dimensional
Echoes appear on the screen as amplitude
spikes
Echoes displayed as a dot in gray scale
Stronger echoes have a higher spikes Stronger echoes are more bright

11. A-scan.
 A-scan (A=amplitude) is used less frequently in other disciplines.
 Employed for biometry and tissue diagnosis.
 In A-scan, the returning echoes are displayed in one dimension.
 Series of waves (spikes) arising from a base line .
 The height of the spike represents the strength of the returning
echo (the basis of tissue diagnosis)

12. 1- Initial spike, 2- Iris spike/ Anterior lens spike. 3- Post lens spike. 4- Base line is
vitreous base line, 5- Retinal spike.

13. SALIENT FEATURES OF A SCAN
 Unique sound amplification system
 Probe design
 Tissue model

14. B-SCAN
 Is a two-dimensional slice of image of ocular tissue.
 It is created from (numerous) A-scan spikes where each spike is
converted to a dot on the display screen; the stronger the echo
source the brighter the dot.
 Thus, the accumulation of numerous dots of various brightness
creates the two-dimensional image of the internal structure of the
eye.

15. TYPES OF B-SCAN
 Low frequency:
Useful in detecting orbital pathology
 Moderate frequency:(7-10MHz)
Useful in globe examination
 High frequency:(30-50MHz)
Useful for anterior segment

16. Its Nothing but the compilation of multiple A scans.
Eye dedicated scans- whose focal zone coincides with posterior globe wall and
anterior orbit

17. SALIENT FEATURES OF B SCAN.
 . Real Time
- B-scan images visualized at approx. 32 frames/second.
- That allows motion of the globe and vitreous to be
easily detected.
- Identify imaged tissues such as detached retina or
mobile vitreous, thus increasing diagnostic capability.
. Gray Scale
- Used to display the returning echoes as a two-
dimensional image.

18.  Time gain compensation (TGC) is an amplification function.
• TGC amplifies deeper signals disproportionally more than superficial
signals.
 Gain is a function of the receiver amplifier that directly affects the
amplitude of displayed echoes.
 Measurement unit is the decibel(dB), which expresses the ratios of
intensities in a logarithmic scale.
 The higher the dB gains, the higher spikes on A-scan and the brighter
dots on B-scan

19. FUNDAMENTAL OBJECTIVES
FOR HIGH QUALITY B SCAN
 Lesion must be in centre of scanning beam.
 Beam must be perpendicular to area of interest.
 Lowest possible decibel gain should be used to increase
resolution of the image

20. INDICATIONS OF USG B SCAN

21. INSTRUMENTATION
 B scan probe is oval/ round in
shape.
 Has a marker that contains a
transducer, gives the orientation
of beam
 Marker indicates the side of the
probe that is represented on the
top of the B-scan screen display

22.  Eg. Area of interest is 3 o’clock
position
- probe at 9 o’clock position
- marker aimed upwards
- center of probe aiming at
3o’clock.
 Area of interest appears in
center of right side of echogram
(the area of best resolution).

23. SCREENING TECHNIQUE
 Methyl cellulose is applied to the
probe.
 Probe is placed on the globe
opposite the area to be examined.
 Probe can also be placed on the
lids, this minimizes patient
discomfort & allows lesser
visualization of posterior fundus.

24. PROBE POSITIONING
 3 basic probe positions:
1. Transverse
2. Longitudinal
3. Axial

25. TRANSVERSE SCANS
 Shows lateral extent of lesion.
 Beam travels many meridians but scanning through lens is
avoided thus produces better resolution.
 Patients gaze directed away from the probe, towards the meridian
being examined.
 Probe placed on the opposite conjunctival surface with marker
parallel to the limbus.

26. Movement of probe from limbs to fornix, scanning opposite to globe
wall.

27. LONGITUDINAL SCANS
 Shows anterior-posterior extent of a lesion along one meridian
only, from the optic nerve(lower part of echogram) to ciliary
body(upper part of echogram).
 Probe placed perpendicular to the limbus.
 Marker directed towards the limbus or the area of interest

29. LONGITUDINAL SCAN OF A
NORMAL EYE
 Shows Optic nerve, post fundus on inferior portion &
peripheral fundus on upper part.

30. AXIAL SCANS
 Patient is asked to fix his gaze in primary
position & probe tip is centered on the cornea.
 Easy to interpret because of evident landmarks
(lens & Optic Nerve)
 Offers less resolution & more distortion because
of attenuation & refraction of sound beam
caused by lens
 Mainly used for easily demonstrate posterior
pole lesion & membrane attachment to optic
nerve head

31.  Technique of ultrasound scanning of the
globe in Axial probe position-
a. Vertical with the marker pointing
towards the brow.
b. Horizontal with the marker pointing
towards the nose.
c. Sections of all other clock hours
positions

32. Mainly used for posterior pole lesion & membrane attachment to Optic
Nerve head

33. AXIAL SCAN OF A NORMAL EYE
 The Optic Nerve is shown at the centre as a sonoluscent
structure surrounded by a highly reflective intraorbital
fat tissues.

34. GENERAL OCULAR SCREENING
 Overlapping 4 Transverse sections of the globe
 Transverse 12
 Transverse 3
 Transverse 6
 Transverse 9
 There are 4 additional transverse scans in oblique
quadrants -

36. NORMAL B-SCAN
 Cornea, AC and Anterior capsule- seen with
immersion technique
 Lens –oval high reflective structure
 Vitreous- acoustically clear
 Retina, choroid and sclera-seen together as a high
reflective structure

37.  Sclera – 100% reflective
 Optic nerve-wedge shaped acoustic void in retrobulbar
space on axial scan
 Extraocular muscles- Echo-lucent to low reflective
structure

38. DIFFERENTIAL DIAGNOSIS OF INTRAOCULAR
LESIONS-
 Topographic
-Location
-Extension
-Shape
 Quantitative
-Reflectivity
-Internal structure
-Sound attenuation
 Kinetic
-Aftermovement
-Vascularity
-Tissue mobility

39. TOPOGRAPHIC ECHOGRAPHY
 Performed to determine its shape, location, extent and
configuration.
 B-scan is ideally suited for initial topographic
evaluation because it provides a two-dimensional
display.
 It is also important to look for a lesion’s topography
added with A-scan.

40.  Abnormal topographic finding classified as –
 Mass lesion
 Membranous opacity
 Single or vitreous opacities
 Abnormality of the globe contour.

44. REFLECTIVITY-
 Evaluated by observing the spike
height on A-scan and the signal
brightness on B-scan.
 On A-scan reflectivity is
determined-
 By estimating the height (i.e.
amplitude) of a lesion’s spikes
in relation to the vitreous
baseline (0%) and the top of the
initial spike (100%)

46. ON B-SCAN-
 Assessment of signal brightness is only a gross
estimation.
 Not as precise as is determining spike height on A-scan.
 Signal must be compared with that of either the normal
highly reflective (echo-dense) sclera or the very low
reflective (echo-lucent) vitreous cavity

47. INTERNAL STRUCTURE
 Evaluated by noting the differences in height and length of the
A-scan spikes and difference in echo-density on B-scan
echograms
 Regular internal structure
-homogenous architecture
-little or no variation in height and length of spikes on A-scan
-uniform appearance of echos on B-scan

48.  Irregular internal structure
-heterogenous architecture
-marks differences in echo appearance
 Moderately irregular structure
-slight variations in echo appearance

50. SOUND ATTENUATION-
 Occurs when the sound energy is scattered, reflected or absorbed
by a given medium.
 Indicated by progressive decrease in the strength of echoes, either
within or posterior to the lesion.

51.  Bone, calcium, and most foreign bodies produce strong
sound attenuation.
 Results in decreasing signal strength or an actual void
posterior to the lesion referred to as shadowing

52. KINETIC ECHOGRAPHY
 Mobility (After movement)
-observing motion of the echoes
-non solid lesion (e.g. vitreous membrane) displays after movement,
whereas a solid lesion (e.g. tumor) does not.
 Vascularity
-fast spontaneous motion of blood flow within vessels.
 Convection movement
-slow spontaneous movement of -convection currents of fine particles.
-e.g. cholesterol debris within a large cavity (e.g. vitreous cavity).

53. VITREOUS-
 NORMAL : Echo-lucent
 AGEING : Low reflective
vitreous opacities & PVD (seen
as mobile, thin, low reflective
line).

54. POSTERIOR VITREOUS
DETACHMENT
Can be total or partial.
On B scan detached posterior face is smooth & may be
thick if layered with blood.
In PVD with normal eye: reflectivity is low so high gain
is required.
In PVD with hemorrhage: reflectivity is extremely high.

55. ASTEROID HYALOSIS
 Multiple pinpoint, highly
reflective vitreous opacities
 Opacities move with eye
movement
 Echo free space just in front of
retina
 Called as “Starry eye”

56. VITREOUS HEMORRHAGE
Gain must be increased to visualize vitreous echo in a
patient suspected to have a VH.
Fresh VH Old VH
Echolucent or low reflective
mobile small dots or linear areas
Varying reflectivity multiple
large opacities
Varying position More dense inferiorly due to
gravity

57. Vitreous hemorrhage Asteroid hyalosis
Low reflectivity
Disappears when gain reduced to 60
dB
Highly reflective
Visible when gain reduced upto 60
dB

58. VITREOUS INFLAMMATION
 Clumps of inflammatory cells-
scattered particles or large aggregates.
 Dense echogenic collections in
posterior segment.
 Assessing the severity & extent of
inflammation in a patient suspected of
endophthalmitis.

59. Dislocated lens
 Round or globular structure in posterior vitreous &
strand of vitreous may be attached to dislocated lens.

60. TRAUMA
 Membranous track which may end in the vitreous cavity
or at an impact site opposite the entry site.
 Following the track may lead to an Intra ocular foreign
body at an impact site or exit site.
 Foreign body can be precisely localized.

61. Posterior globe rupture
 Breach of scleral & choroidal tissue with associated
choroidal thickening

62. INTRA OCULAR FOREIGN BODY
 Metallic foreign body:- Very bright signals that
persist on lowering gain
 Produce very high reflectivity on A-scan
 Non metallic foreign body:- More challenging,
produce bright signals.

63. RETINAL TEAR
 Can be detected using
longitudinal approach.
 Posterior vitreous hyaloid may
be attached to the retinal flap.
 Shallow cuff of SRF may
accompany the tear.

64. RETINAL DETACHMENT
Highly reflective undulating
membrane
Initially RD is mobile
Translucent sub-retinal space

65. LONG STANDING RD:
Retinal cysts may be present
RD may become partially calcified
Sub-retinal space is filled with cholesterol debris

66. TRACTIONAL RD:
Vitreoretinal tractional bands: focal/broad
Vitreoretinal tractional bands: focal/broad

67. EXUDATIVE RD:
 Configuration of detachment is convex & bullous

68. RETINOSCHISIS
 Clinical differentiation from
RD is difficult.
 Retinoschisis is more focal,
smooth, dome shaped & thin
membrane usually involving
inferotemporal fundus.

69. RETINOBLASTOMA
 U/L or B/L.
 B scan is commonly used for
the initial & follow up of
retinoblastoma.
 Small tumor: smooth, dome
shaped with low to medium
reflectivity.
 Large tumor: Irregular shape &
highly reflective as amount of
calcium increases.

70. PERSISTENT FETAL VASCULATURE
 U/L condition
 Seen in longitudinal scan as very thin
vitreous band (persistent hyaloid
vessel) extending from the posterior
lens capsule to the optic disc
 Retrolental membrane may be
present
 In severe cases traction or total RD
may be associated

71. RETINOPATHY OF PREMATURITY
 B/L disease
 Affects mainly the vitreous and
peripheral retina
 Retinal loops
 USG can detect the funnel shaped
RD present in stage 5 disease

72. COATS DISEASE
 U/L condition.
 Presence of cholesterol in the sub-retinal space.
 Retina is thickened in the area of telangiectasia.

74. CHOROIDAL DETACHMENT
 Smooth, dome shaped membrane that does not insert on
optic nerve
 May be localized or involve entire fundus (kissing CD)

76. CHROIDAL MELANOMA
 Solid consistency
 Collar button (i.e. mushroom) shape - pathognomic
-when tumor breaks through the bruch’s membrane
 Low to medium internal reflectivity
 Regular internal structure
 Internal blood flow (i.e. vascularity)

77.  Sound attenuation:
Large melanomas produce
significant internal sound
attenuation
 Choroidal excavation:
- Noted at the tumor base
thought to be caused by
tumor infiltration of the
normal choroid

78.  Posterior scleral bowing-
-caused by increased concavity of
the sclera underlying the tumor

79. Metastatic choroidal carcinoma
 Appear diffuse, typical bumpy & irregular contour with
central elevation.

80. Choroidal hemangioma
 Acoustically solid lesion
with the sharp anterior
surface & high internal
reflectivity but without
choroidal excavation &
orbital shadowing

81. Choroidal naevus
 Localized flat or slightly elevated lesion with internal
acoustic reflectivity

82. CHOROIDAL COLOBOMA
 Excavation of posterior
pole with sharp edges
 Associated features:
microphthalmos & RD

83. SCLERA
 Posterior staphyloma
 Shallow excavation of posterior pole with smooth
edges in highly myopic eyes

84. POSTERIOR SCLERITIS
 Scleral thickening
 Scleral nodules
 Fluid in tenon space
leading to accentuation
of reflective space seen
as “T sign”

85. OPTIC NERVE
 OPTIC DISC CUPPING

86. OPTIC DISC DRUSEN
 Calcified nodules that produce echoes of high reflectivity at or within
optic nerve head

87. PAPILLOEDEMA
 Increased subarachnoid fluid
around the optic nerve
 Crescent sign
-An echo-lucent circle within the
optic nerve sheath (separating the
sheath from the optic nerve)

88. ORBITAL ULTRASONOGRAPHY

89. SCAN POSITIONS

90.  Trans-ocular- lesions within
posterior and mid aspects of
orbit
 Para-ocular- lesions within
lids or anterior orbit.

91. HYDATID CYST
 Cystic lesion in the intraconal space
 “Double wall sign” from the wall of endocyst and ectocyst

92. CYSTICERCOSIS
• Ultrasound B-scan shows
curvilinear high echo corresponding
to the cyst wall of intravitreal
cysticercosis.
• Note the high amplitude of the
anterior and posterior cyst wall and
lack of echogenicity inside the cyst
on the A-scan

93. UBM ULTRASOUND ( BIOMICROSCOPY )
 Similar to optical biomicroscopy i.e. observation of
living tissue at microscopic resolution
 UBM is a newer ultrasound technology introduced by
Pavlin and colleagues.
 Deals with frequency range of 50-100 MHz

94. HIGH FREQUENCY ULTRASOUND :-
 To produce images at near microscopic resolution.
• Tissue micro-imaging.
• Higher frequencies (50 - 100 MHz).
• Resolutions 15 to 100 micrometres .
• Penetration ranging from 2 - 5 mm.
• Two dimensional grey scale imaging of eye.

95. PRINCIPLE
• Achieving goal of real time B-mode imaging at higher frequencies has
been facilitated by development of three modifications:-
• - Transducers
• - High frequency signal processing
• - Precise motion control
• Polyvinylidene di-fluoride (PVDF) is used as the piezoelectric polymer.

96.  50-100 MHz transducer is moved linearly over the imaging field
up to 4 mm collecting radiofrequency ultrasound data.
 This radiofrequency travels the body tissue and is reflected back
to the transducer. The reflected radio frequency is processed by
the signal processing unit to produce an image.

97. 0 1000 2000 3000 4000 5000
Bone
LENS
Muscle
BLOOD
Soft tissue
AQU / VIT
Water
Fat
Air
4080
1641
1580
1570
1540
1532
1480
1450
330
Propagation Velocity (m/s)
Propagation Velocity (m/s)

98. DIFF B/W CONVENTIONAL USG AND
UBM
 USG Bio-microscopy
• Frequency 50-100MHz.
• Higher resolution 20-50
microns.
• Limited depth
penetration and smaller
angular field.(5mm for
50MHz UBM).
 Conventional USG
• Frequency 7.5-10MHz.
• Lower resolution 0.5-
1mm.
• Greater depth penetration
100mm

99. UBM MACHINE

100. TECHNIQUE
 The patient is in supine position and the eye
is open. Topical anesthesia is instilled
 Methylcellulose, distilled water can be used
as coupling agents
 The UBM uses a speed of sound constant of
1500 m/s to convert time to distance
measurements
 There is a special cup which fits in between
the eyelids, keeping them open.

101. FUNCTIONAL MODALITIES
The basic functional modalities of UBM include:
 B mode :- provides two-dimensional images of the
organs such as eye and tumor.
 M mode :- displays the dynamic positional change of
moving structures such as iris with accommodation.
 3D reconstruction measure the tissue volume, and
demonstrate the surface image of the structures.

102. NORMAL CORNEA STRUCTURE
epithelium
bowman’s
membrane
stroma
Descemet’s
membrane
endothelium

103. ANTERIOR CHAMBER
 AC DEPTH- axial distance from the internal
corneal surface to the lens surface
 Can be taken from any point on the endothelial
surface to either the iris or lens surface.

104. CORNEALAND SCLERAL
DISEASE
 Helpful in patients with opaque corneas
prior to transplantation.
 Corneal Edema can be assessed.
 Also helpful in scleritis, differentiation
between intra-scleral and extra-scleral
disease and assessment of degree of scleral
thinning

105.  ANTERIOR CHAMBER ANGLE
REGION
 The corneoscleral junction and scleral spur
can be distinguished consistently.
 Scleral spur - important landmark for
measurement in angle region

106. IRIS
 Iris epithelium- highly reflective layer on the posterior iris
surface. This defines the posterior iris border.
 Useful in differentiating intra-iris lesions from lesions
behind the iris.
 Iris curvature -a line from the iris root to the iris tip and
measuring the deviation of the iris epithelium from this line

107. ZONULES -
 The anterior zonule and the lens surface can
be easily seen in all eyes.
 The zonule inserts smoothly into the surface
of the lens.
 But is sometimes more irregular , which
may indicate the degree of zonular tension

108. UBM IN OCULAR DISEASE
 Glaucoma: examples of use in glaucoma
 Pupillary block
 Iris assumes a convex profile due to the
pressure differential between the PC and
AC.

109.  After peripheral iridotomy (arrowhead), the angle (arrow) has
opened

110. Anterior synechiae
- The iris takes an angular form .
- The state of the angle behind the
synechiae can be defined by UBM

111. SUPRACILIARY EFFUSIONS AND
MALIGNANT GLAUCOMA
 Supraciliary effusions
 Inflammatory diseases
 Vein occlusions
 Following RD Surgery
 They produce rotation of the ciliary processes and iris
 This can result in angle closure

112. PIGMENTARY
DISPERSION-
 Loss of pigment from the pigment epithelial
layer of the iris and deposition in the TM
leading to Glaucoma.
 It is due to reverse pupillary block-posterior
bowing of the iris and leading to iris-zonule
contact with mechanical pigment loss.

113. ANTERIOR SEGMENT TUMOURS
 Useful tool in the management of anterior segment tumors
 It provides a clear image of even the smallest anterior segment lesions.
 UBM allows improved classification and the ability to determine Ciliary
body involvement

114. IRIS TUMOURS-
 On UBM internal reflectivity, depends upon the
degree of internal vascularity
 Margins can be defined, important for assessing
involvement of the ciliary body
 A change in shape can also be imaged

115. CILIARY BODY TUMOURS
 Small lesions (<4mm in depth) can be defined
by UBM.
 Precise localization of the posterior and lateral
boundaries.
 Extra-scleral extension can be localized.

116. Nodular anterior scleritis
appears as fusiform thickening
of limbal sclera Necrotizing scleritis with thinning

117. FOREIGN BODY IN THE ANGLE
 An Ultrasound biomicroscopic image
showing metallic foreign body (arrow) and
its shadowing effect in the ciliary body

118. CONJUNCTIVAL AND ADNEXAL DISEASE
 Differential diagnosis of tumors
 Judging the depth of conjunctival and limbal lesions
 Imaging canalicular conditions.

119. THANK YOU

120. THANK YOU