B SCAN

1. B – SCAN ULTRASONOGRAPHY


Dr. Parameshwar Rao
Dr. Haridev
Dr. Ashok
Dr. Siva Kumar.W (PG)

2. INTRODUCTION
B-scan ultrasonography is an important
adjuvant for the clinical assessment of
various ocular and orbital diseases.
 This presentation is designed to
describe the principles, techniques, and
indications for echographic examination,
as well as to provide a general
understanding of echographic
characteristics of various ocular
pathologies.

3. B- SCAN is a two dimensional imaging
system which utilises high freq sound
waves ranging from 8-10 MHz.
B stands for bright echoes.

4. B - SCAN
It was first introduced by Baum and
Greenwood in 1958
First commercially available B scan is
developed by Coleman et al in seventies
The importance of the instrument and
technique is emphasised by Karl Ossoinig

5. Physics:
It is an acoustic wave that consists of particles
within the medium
Frequencies used in diagnostic ophthalmic
ultrasound are in the range of 8-10 MHz

These high frequencies produce shorter wave
lengths which allow good resolution of minute
ocular and orbital structures

6. Multiple short pulses are produced with a
brief interval that allows the returning
echos to be detected, processed and
displayed.
The basis of the echo system is
piezoelectric element which is a quartz or
ceramic crystal located near the face of the
probe

7. sound waves from
transmitter

Echoes are received
by receiver

Amplification
Oscilloscope screen
Target tissue

9. Low frequency: orbital tissue
Medium frequency : ( 7 – 10 mhz )
Retinal , vitreous , optic nerve
High frequency : ( 30 – 50 mhz) :
ant chamber upto 5 mm
Types of frequency

10. IMPEDENCE : The difference between
the strength of the returning echoes
from tissues with abrupt changes in
acoustic properties.
GAIN : Increase in gain is associated
with increase in tissue penetration and
sensitivity but decrease in resolution.

11. HIGH FREQUENCIES - LOW
PENETRATION BUT GOOD
RESOLUTION.
(abdominal US-1-2MHz )
 INCREASE IN GAIN - INCREASE IN
TISSUE PENETRATION AND
SENSITIVITY – DECREASE IN
RESOLUTION.

12. INCREASE IN GAIN - INCREASE IN TISSUE
PENETRATION AND SENSITIVITY – DECREASE IN
RESOLUTION.

13. DISPLAY MODES: A SCAN/ B SCAN /
BOTH
TIME GAIN COMPENSATION: to
enhance echoes from deeper
structures.

14. AMPLIFICATION
Three types are commonly used.
1. Linear : Can show minor differences in
echos . Limited range .(A SCAN)
2. Logarithmic : Wider range. Minor
differences cannot be seen.(B SCAN)
3. S Curve : Combines the benefits of both
the above.(in the standardized A SCAN for
tissue differentiation)

15. The probe has ‘ Dampening material’ which
limits the vibrations of the crystal thus
shortening the pulse
Shape of the crystal is useful in determining
the character of the sound beam
The electrical signal produced by returning
echos is of very weak radio frequency signal

16. This signal undergoes complex
processing before displayed on the
screen
Adjust the amplification of the signal
displayed on the screen, this is referred
as ‘gain’ or ‘sensitivity’ of the instrument
The higher the gain level the greater the
sensitivity of the instrument

17. It produces Two dimensional section
It uses both horizontal and vertical
dimensions of screen to indicate
configuration and location
A section of tissues is examined by
an oscillating transducer
Instrumentation:

18. An echo is represented by a dot on the
screen
The probe is filled inside with a fluid , a
crystal oscillates sending sound waves
out in a fan like array called Sector
scan

19. Image documentation modes :
They are of 2 types
stationary/static
moving/dynamic

20. The images may be saved in different
methods
4.Polaroid photographs
5.35 mm photo
6.Ink prints
7.Thermal prints
8.Videotapes

21. Anterior segment:
2.Opaque ocular media (i.e. corneal opacities)
Pupillary membrane
Dislocation / Subluxation lens
Cataract / after cataract
Posterior capsular tear
Pupillary size / reaction
8.Clear ocular media
Diagnosis of iris and ciliary body tumors
Indications:

22. Posterior segment:
2.Opaque ocular media
Vitreous haemorrhage
Vitreous exudation
Retinal detachment (type / extent)
Posterior vitreous detachment (extent)
Intraocular foreign body (size/ site/ type)
8.Clear ocular media
Tumour (size/ site/ post treatment follow up)
Retinal detachment (solid / exudative)
Optic disc anomalies
3. ocular trauma

23. The patient is
either
reclining on a
chair or lying
on a couch.
The probe can
be placed
directly over
the
conjunctiva or
the lids.
Examination technique:

24. Probe positions
Transverse : most common
Lateral extent, 6 clock hours
Longitudinal : radial ,1 clock hrs, AP
diameter in Retinal tumors and tears
Axial : lesion in relation to lens and
optic nerve .

25. Transverse scan
EYE anaesthetised.
EYE – looking in the direction of observer’s
interest
PROBE –parallel to limbus and placed on
the opposite conjunctival surface
PROBE MARKER – superior (if examining
nasal or temporal) or nasal(if examining
superior and inferior).
6 clock hrs examined at a time.

26.  The clock hour which the marker faces
is always at the top of the scan.
 The area of interest in a properly done
transverse scan is always at the centre
of the right side of scan.
If examining nasal area -12 – 6 clock hrs
temporal - 6- 12 clock hrs
superior - 9 -3 clock hrs
inferior - 3- 9 clock hrs

27. NASAL AREA TEMPORAL AREA

28. SUPERIOR AREA INFERIOR AREA

30. Longitudinal scan
EYE Anaesthetised.
EYE - looking in the direction of observer’s
interest.
PROBE – perpendicular to the limbus and
placed on the opposite conjunctival surface.
PROBE MARKER- directed towards the limbus
or towards the area of interest regardless of the
clock hour to be examined.
Optic nerve shadow always at the bottom on
the right side.
1 clock hour.

31. Axial scan
 EYE anaesthetised.
 EYE – in primary gaze
 PROBE – centered on the cornea .

32. LENS: Oval highly reflective structure
with intralesional echoes with none to
highly reflective echoes.
 VITREOUS is echolucent.
 RETINA, CHOROID AND SCLERA:
Are seen as a single reflective high
structure.

33. OPTIC NERVE : Wedge shaped acoustic
void in the retrobulbar region.
EXTRA OCULAR MUSCLES : Echolucent

to low reflective fusiform structures. The
SR- LPS complex is the thickest. IR is the
thinnest. IO is generally not seen except in
pathological conditions.

34. ORBIT -highly reflective due to orbital
fat.
Always examine the other eye before
coming to a conclusion regarding the
lesion .
Opacities produce dots or short lines
Membranous lesions produce an
echogenic line

35. Anterior segment evaluaton
Immersion technique
High resolution technique

36. ULTRASONOGRAPHIC

CHARACTERISTICS

37. VITREOUS HAEMORRHAGE
To detect extent,
density, location
and cause
Fresh haemorrhage
shows dots or lines
Old haemorrhage
the dots gets
brighter

38. POSTERIOR VITREOUS DETACHMENT
Posterior vitreous
detachment:
The detached
posterior vitreous
is seen as
membranous
lesion with
no/some
attachments to the
optic disc

39. POSTERIOR VITREOUS DETACHMENT
Mobility of PVD is
more than RD.
The spike of RD is
more than PVD.
PVD becomes more
prominent in higher
gain settings

40. RETINAL DETACHMENT
The detachment
produces a bright
continuous, folded
appearance with
insertion into the disc
and ora serrata.
It is to determine the
configuration of the
detachment as shallow,
flat or bullous

41. EXUDATIVE RETINAL DETACHMENT

42. RHEGMATOGENOUS RD

43. RHEGMATOGENOUS RETINAL DETACHMENT

44. CLOSED FUNNEL RD WITH
RETINAL CYST

45. CLOSED FUNNEL RD WITH
RETINAL CYST

46. APPEARS AS RD BUT IT IS A PVD.
CLUES: NON UNIFORM THICNESS OF MEMBRANE
VERY THIN ATTACHMENT TO THE DISC.

47. RETINAL TEAR

48. RETINAL TEAR WITH FREE SUPERIOR END .
THE MEMBRANE IS CONVOLUTED ON ITSELF.
POSTERIOR VITREOUS IS ATTACHED AT THE
SUPERIOR END OF THE TEAR.

49. ASTEROID HYALOSIS
Asteroid hyalosis:
Calcium soaps
produce bright
point like echos

50. Differentiation, extrascleral extension,
size, assessing tumour growth or
regression.
Measurement of tumour dimensions
such as elevation and base.
Help in distinguishing solid from cystic
lesions.
TUMOURS

51. RETINOBLASTOMA
Size of the tumour
Shows irregular
configuration
Calcification
shows high
internal reflectivity

54. Collar button or mushroom shape.Large tumours shows
acoustic hallowing
MELANOMA

55. TUMOURS - OSTEOMA

56. CHOROIDAL DETACHMENT
KISSING CHOROIDS
Smooth, thick, dome
shaped membrane in the
periphery with very little
after movement
360 degree detachment
shows a pathognomonic
“scalloped appearance

57. CHOROIDAL DETACHMENT
KISSING CHOROIDS

58. CHOROIDAL DETACHMENT

59. Intraocular foreign bodies:
Localisation and extent of intraocular damage
Metallic foreign bodies produce very high
bright signal
Shadow present posterior to the foreign body
Wood, glass and organic material produce
specific echographic finding

60. INTRA OCULAR FOREIGN BODY

61. CUPPED DISC

62. MACULAR EDEMA

63. PERSISTENT HYALOIDAL VESSEL

64. POSTERIOR STAPHYLOMA

65. LACRIMAL GLAND TUMOUR

66. NANOPHTHALMOS

67. RETINOSCHSIS

68. Retinoschisis:
Smooth, thin dome shaped membrane that
doesn’t insert on optic disc
Diabetic retinopathy:
Nature and extent of the disease
To monitor progress of the disease
Aids in pre – vitrectomy evaluation

69. ENDOPHTHLMITIS

70. CYSTICERCOSIS WITH RETINAL
TEAR

71. COLOBOMA OF THE CHOROID
AND DISC

72. PERSISTENT FETAL VASCULATURE

73. RETINOPATHY OF PREMATUIRITY

74. POSTERIORLY DISLOCATED LENS

75. INTRA OCULAR AIR / GAS

76. SILICON OIL FILLED VITREOUS

77. Sclera:
Thickening in hyperopic and
nanopthalmic eyes
Infolding in severe hypotony or a
ruptured globe

78. SCLERITIS

79. Normal muscles show less echo dense than
surrounding orbital soft tissue
Documenting the gross size and contour of a
muscle
’
Evaluation of extraocular muscles:

80. Nodular posterior scleritis with fluid in the
Tenon capsule.
Positive T-sign at the insertion of the optic nerve.

81. Evaluation of optic nerve
General topography, relationship to
structures, optic disc anomalies and
alteration in contour of the globe
The subarachnoid space surrounding
optic nerve appears as echolucent
cresentric or circle around the nerve
called ‘Doughnut sign’

82. Non invasive
Performed in an office setting
Does not expose to radiation
High resolution echography provides reliable
and accurate assessment
Ideal for follow up of lesion
Advantages:

83. Disadvantages
High frequency sounds waves have
limited penetration

84. Useful in the following conditions:
Abnormal size of eye
Abnormal shape of eye
Congenital abnormalities
Vitreous alterations
Retinal detachments (type/ location)
Ocular and orbital tumours
Trauma
ULTRASONOGRAPHY IN PAEDIATRIC PATIENTS:

85. Artefacts:
Insufficient fluid coupling ( i.e., lack of
methyl cellulose) cause entrapment of
air between the probe and eye leading
to display of bright echos which
represent multiple signals
PITFALLS

86. REVERBERATION ARTEFACTS

87. ANGLE OF INCIDENCE ARTEFACT

88. PITFALLS
Tumours:
Mass may be missed is less than 0.75
mm
False –ve results in case of small
lesion and fibrotic tissue
False + ve in subretinal haemorrhage
and metastatic tumour with massive
infiltration

89. Vitroretinal disease:
In RD unable to detect actual tear
In vitrectomsed eyes vitreous
haemorrhage is diffuse leading to
echolucency
Silicon oil decrease in sound velocity
PITFALLS

90. PITFALLS
Intraocular foreign body:
Small Intraocular foreign body of < 1mm
may be missed.
Orbit:
An orbital mass can be detected or
differentiated if > 3 mm in size if anterior and
> 5 mm in posterior orbits.

91. B- SCAN REPORTING
Describe the features and correlate
with clinical findings.
Dont jump to diagnosis.
Always examine both in sitting and
erect postures in case of RD.
Examine other eye also.
Try to take the best picture possible.

92. FOUR TRANSVERSE SCANS
ONE HORIZONTAL AXIAL SCAN TO
EVALUATE THE POSTERIOR POLE ARE
SUFFICIENT.

93. THANK YOU