B Scan Ultrasonography

1. B SCAN USG
Presenter : Dr Samuel Ponraj

2. • B-scan or brightness modulation scan
provides two dimensional images of a series of
dots and lines.
• B-scan provides the topographic information of
shape, location, extension,mobility, and gross
estimation of thickness of the tissue.

4. FREQUENCIES
• 1-2 MHZ : ABDOMINAL ULTRASOUND
• 8-10 MHZ : OPHTHALMIC ULTRASOUND
(B SCAN)
BEST FOR POSTERIOR SEGMENT
• 35- 80 MHZ : ULTRASOUND BIOMICROSCOPY
BEST FOR CORNEA &
ANTERIOR SEGMENT

5. PULSE ECHO SYSTEM
• TRANSDUCER
• AMPLIFIER
• DISPLAY MONITOR

6. ELECTRIC
CURRENT
TRANSDUCER
ULTRASOUND
WAVES
SURFACE
AMPLIFIER
MONITOR

7. TRANSDUCER
• Device which converts Electrical to Sound
energy [pulse ] and Sound to Electrical energy
[Echo]
• Basic Components –
Piezoelectric plate
Backing layer
Acoustic Matching layer
Acoustic lens

8. • Piezoelectric Element : essential part generates
ultrasonic waves . Coated on both sides with
electrodes to which a Voltage is applied.
Oscillation of Element with repeat expanding
and contraction generates a sound wave.
• Most common: Piezoelectric ceramic ( Lead
zirconate titanate).

9. • Backing layer : located behind the piezoelectric
element which dampens excessive vibrations
from probe thereby improves image resolution
• Acoustic matching layer : located in front of
piezoelectric element which reduces the
reflections from acoustic impedance between
probe and object thereby improves trasmission.

10. • Acoustic Lens : gray coloured rubber on tip
helps in focussing the ultrasonic waves as a slit
beam.

15. Frequency Resolution Penetration Possible
Scanning depth
High Fine Weak Shallow
Low Rough Strong Deep

16. IMMERSION B SCAN CONTACT B SCAN

18. PROBE POSITIONING
• TRANSOCULAR APPROACH
1. AXIAL
2. TRANSVERSE
3. LONGITUDINAL
• PARAOCULAR APPROACH

19. Standardized Echography
( Contact B Scan + A Scan)
3 Basic Positions :

29. VOCABULARY

30. • Bell : Measurement of Sound Intensity
• Hertz : Frequency of transducer
• Acoustic impedence mismatch:
- Resistance of tissue to passage of Sound waves.
Difference of two tissues at the Interface.
- Homogeneous ( Vitreous)- Sound passes through
tissue with no returning signal.
-Heterogeneous (Orbital Fat) - Different levels of
Acousitc impedance mismatch within tissue.

31. • Echo – Reflected Sound wave.
• Anechoic – No Echo.
• Attenuation : Sound is absorbed ( Tumours)
• Shadowing : Sound is strongly reflected , nothing
passes through it.(Choroidal Osteoma
Drusen of Optic nerve head , Air bubble).
• Reverberation : Collection of Reflected sounds
bouncing back and forth between
tissue boundaries especially
( Foreign Body in Eyeball )

32. Ultrasound Velocity
• Normal Phakic eyes = 1555 m/s
• Aphakic eyes = 1532 m/s
• Pseudophakic eyes (PMMA) = 1556 m/s
(Acrylic )= 1549 m/s
• Silicon Oil filled eyes = 980 m/s

33. Normal Ultrasonography Characteristics
Lens :Oval highly reflective structure
Vitreous : Echolucent
Retina , Choroid , Sclera : Each is single highly
reflective structure.
Optic Nerve :Wedge shaped acoustic void in
Retrobulbar region
Extraocular muscles :Echolucent low reflective
fusiform structure.
Orbit : Highly reflective (Orbital fat)

35. Indications
A. Opaque Media (Pathology of Posterior segment)
B. Transparent Media

36. Opaque Media (Anterior)
• Dense Cataract
• Miosis
• Hyphaema
• Hypopyon
• Corneal Opacity
• Plan for Penetrating keratoplasty with Opaque
Anterior segment.

37. Opaque Media (Posterior)
• Vitrous Haemorrhage
• Vitritis/ Endophthalmitis
• Pupillary or Retrolenticular membrane

38. Transparent Media
• Acquisition of Axial Length for Highly Myopic
surgical Candidates ( Caution for Posterior
Staphyloma)
• Inaccurate A – Scan data (Determination of
dimensions of Eye ball)
• Proptosis( Poorly represented Orbital Apex)
• Orbital tumours
• Carotico- cavernous fistula(Dilated Ophthalmic
vein)

39. • Cysticercosis of Extraocular Muscles
• Suspected Intra Orbital Foreign Body
• Orbital Cellulitis
• Iris & Ciliary body anomalies
• Optic Disc anomaly
• Retinal Detachment (Rhegmatogenous /Exudati
ve – shifting fluid)
• Choroidal Detachment.

40. HOW TO APPROACH A
DIAGNOSIS ??

41. 1. Examination of each quadrant
2. Look at each quadrant
- coronal
- sagital
3. Mentally assemble the Cross sections
4.Anticipate how it should look on
moving probe.

42. Pathological Ultrasongraphy
characteristics

43. Multiple Fine Echo Opacities within the Vitreous Cavity suggestive of
Vitreous Haemorrhage .

44. Multiple, densely packed, homogeneously distributed echodense dots of
medium to high reflectivity with a Clear Preretinal space suggestive of
Asteroid Hyalosis

45. Moderately elevated thin smooth dome-shaped membrane
echo (arrow) located in the inferotemporal periphery suggestive of
Retinoschisis

46. KISSING CHOROIDALS

47. • Smooth, dome shaped ,
• thick, less mobile with
• double high spike suggestive of
Choroidal Detachment

48. PVD RD CD
Topographic Smooth, with or
without disc insertion
Smooth or folded
with disc insertion
Smooth without
disc insertion
Quantitative < 100 % spike 100 % spike Double 100 % spike
Kinetic Marked Moderate None

49. PVD or RD ?
• RD attached to the OD
• RD is high reflective
• RD is less mobile
• Rd is 100% amplitude
• Reflectivity of the periphery
can differentiate between the
two in difficult situations like
trauma and inflammations .

50. Differentiating features of RD
Rhegmatogenous RD Tractional RD Exudative RD
Convex elevation ,
Undulating folds, PVR
Concave
elevation,Fibrous
tractional band
Convex elevation,
Shifting fluid
changes
Configuration
with postural
change

51. RD configurations
Open Funnel
Triangular
Closed funnel ( T shape)

52. Long standing RD
Closed funnel RD with
PVR
Retinal cysts

53. Configurations of TRD
Tent like ( point adherence )
Tabletop ( broad adherence )
Hammock appearance ( multiple tent)

54. Highly reflective, echo-dense nodule located in Vitreous Cavity suggestive
of Cysticercosis.

55. Collar stud pattern ( Mushroom shape )
Regular internal structure , Acoustic shadowing
Low to medium reflectivity , Internal vascularity suggestive of
Choroidal Melanoma

56. Small globe , Retrolenticular membrane
A Moderate Reflective band extending from the optic disc
to the posterior lens capsule suggestive of PHPV.

57. Globular/Oval Echoic structure in Posterior Vitreous signifying a
Dislocated Lens

58. T sign collection of fluid in subtenon space suggestive of Posterior Scleritis .

59. Posterior Staphyloma in High Myopia