The document covers a workshop on basic ultrasound guidance for pain management, highlighting the importance of real-time visualization for accurately targeting nerves while noting limitations such as operator dependence and the need for substantial training. It details essential techniques for image capture, optimization, and interpretation, emphasizing the proper selection of equipment and scanning methods. Furthermore, it addresses common artifacts that can affect image clarity and the significance of understanding anatomy for effective ultrasound-guided procedures.

1. BASIC ULTRASOUND GUIDING
ALAMSYAH AMBO ALA HUSAIN
WORKSHOP BASIC USG FOR PAIN MANAGEMENT
Novotel, 2-3 Desember 2023

2. INTRODUCTION
• view an image of the target nerve directly
• guide the needle under real-time visualization
• navigate away from sensitive anatomy
• monitor the spread of LA
• block nerves at any point along their course, without relying on previously
used landmarks
• make real-time procedural adjustments.

3. LIMITATION OF ULTRASOUND
• Relatively superficial structures could be examined.
• Operator dependent. (experiences, skills and knowledges)
• Relatively machine dependent (the quality of transducer or probe)
• Long learning and practice. ‘’Hundred times seen not as once performed’’

4. • It is important to understand how to obtain and capture an image, differentiate true
image from artefact, introduce a needle, place it close to the nerve, and deliver LA
to surround the nerve.
• The components required to achieve this are:
• Image capture
• Image optimization
• Image interpretation
• Needling techniques.

5. IMAGE CAPTURE
• Machine
• Probe choice
• Acoustic coupling
• Scanning technique
• Short-axis and long-axis views

6. IMAGE CAPTURE
• Machine
• rapid development of good quality portable ‘lap top’ machines, and progress continues
to advance.
• Many companies now produce machines that offer quality and resolution capabilities
adequate for use in regional anaesthesia and pain management.
• Machines should include basic image optimization features, technique specific settings
(nerve or vascular imaging), Doppler function, image storage features, and a number of
enhanced imaging techniques such as tissue harmonics and multibeam technology as
standard.

7. ULTRASOUND THEORY
• Ultrasound waves are emitted from the transducer.
• Change in acoustic impendence, such as at tissue
interfaces, echoes are produced that are received by
the transducer.
• The delay in receiving the echo by the piezoelectric
elements and the intensity of the echo are used to
produce a two-dimensional ultrasound image, called
a B (brightness)-mode image.

8. IMAGE FORMATION PROCESS
• The signal from a beam along
the dotted line in the image
(right) is plotted as a function of
time (left), along with the
detected power vs the
corresponding depth (centre),
which is then mapped to grey
scale value in the image.
• The complete image for a single
frame is formed by repeating this
process for each beam across
the Regio Of Interest (ROI).

9. IMAGE CAPTURE
• Probe choice ( 2 key concepts )
• Resolution (frequency)
• Penetration (depth)

10. IMAGE CAPTURE
• Acoustic coupling
• US waves are rapidly attenuated by air → no air between the probe and the skin.
• an acoustic couplant is needed → added advantage of acting as a lubricant.
• Any water-based gel or alcohol skin disinfectant can be used.
• No oil based couplants → damage to the transducer.
• Probe covers recommended in all cases to protect both probe and patient.
• These can range from a glove or clear plastic dressing, to a purpose designed cover.

11. IMAGE CAPTURE
• Scanning technique
• basic hand/transducer movements, are
employed to improve view and locate
the target structure.

12. USEFUL SCANNING TECHNIQUE ARE:
• Sliding: is when the transducer is moved
over the surface of the skin. This is
essential for locating structures.

13. USEFUL SCANNING TECHNIQUE ARE:
• Tilting: is where the transducer is angled
on its short axis (from side to side). This
movement is used to extend the field of
view.

14. USEFUL SCANNING TECHNIQUE ARE:
• Rotating: is where the transducer is moved
from, for example, transverse to sagittal
view. Rotating is necessary to move from a
short axis to a long axis view of a structure.

15. USEFUL SCANNING TECHNIQUE ARE:
• Rocking: is where the transducer is angled
on its long axis (to and from the orientation
marker). This movement is also used to
extend the field of view.

16. USEFUL SCANNING TECHNIQUE ARE:
• Compression: is where more or less
pressure is placed on the transducer. It can
be used to differentiate veins from arteries.
Veins can easily be compressed, whereas
arteries cannot.

17. IMAGE CAPTURE
• Short-axis and long-axis views
• how the image of the target structure is
visualized.
Short-axis view :
Probe side on Beam across target nerve
Long-axis view
Probe end on Beam along length of target nerve

18. SHORT AND LONG AXIS IS BASED ON THE POSITION OF THE
PROBE WITH REFERENCE TO THE AXIS OF STRUCTURE

19. IMAGE OPTIMIZATION
Once the target structure has been identified it is important to optimize the image by making
adjustments to:
• Pre-sets
• designed to optimize image quality for individual probes and different tissue types.
• Standard pre-sets are: nerve, vascular, musculoskeletal, breast, and small parts.
• Depth
• adjusted to keep the target structure in the middle of the screen.
• allows visualization of all the structures around the target and is also frequently the best focused area of the image.
• Gain
• Gain, or contrast, should be set so that it is consistent throughout the screen. This is important as echoes from
similar structures should give rise to similar screen brightness, regardless of their depth.
• Focus
• On some machines the focus is fixed to the middle of the screen. If not, then it is important to adjust the focus to
the depth of the target structure in order to maximize resolution.

20. IMAGE OPTIMIZATION - PRE-SETS
Selecting the correct application preset is similar in that it will automatically select the ideal frequency,
depth, and gain for that application

21. IMAGE OPTIMIZATION - DEPTH
• Ultrasound Depth Marker (4cm in this
example)

22. IMAGE OPTIMIZATION - GAIN
• Ultrasound gain simply means how bright or dark you want your image to appear. It increases
or decreases the strength of the returning ultrasound signals that you visualize on the screen.
Undergained Overgained Optimal

23. IMAGE OPTIMIZATION - FOCUS
• Bidirectional arrows along the right border of
the image indicate the focus level setting.
a) Correct focus setting for viewing the median
nerve (MED) in the forearm.
b) The focus level is set too shallow.
c) The focus level is set too deep.

25. IMAGE INTERPRETATION
• Image interpretation is a critical part of successful Ultrasound Guiding.
• Requires a good knowledge of anatomy, an understanding of the appearance of
different tissues, consideration of how artefact can affect images, and familiarity
with the methods available for interrogating a structure to aid its identification.
• Important factors include:
• Echogenicity
• Sonographic appearances
• Peripheral nerves
• Artefact
• Interrogation

26. ECHOGENICITY
• The degree to which the US beam reflects from a structure and
returns to the probe determines the returning signal intensity.
• This creates images that are black, white, or varying degrees of grey:
• Structures that strongly reflect the US beam generate large returning signal
intensities at the transducer and appear white or hyperechoic.
• Structures that only weakly reflect US generate lower signal intensities and
appear darker or hypoechoic.
• Structures that reflect none of the US beam appear black or anechoic.

27. ECHOGENICITY
• Black arrow, blood vessel (radial artery);
• White arrow, nerve (median);
• White star, muscle;
• White triangle, bone cortex (radius).

28. SONOGRAPHIC APPEARANCES
• Pattern recognition of the different tissues is critical to identification.
• This is aided by observing their real-time interaction with the US probe and beam
(compression, pulsation, anisotropy, and Doppler shift).
Tissue US appearance
Artery Anechoic (black circles or tubes)—pulsatile
Vein Anechoic (black circles or tubes)—compressible, dilate with Valsalva (jugular, subclavian, femoral)
Tendon
Fibrillar
appearance
Long axis—tubular structure
Internal architecture, loosely packed continuous blurred bright lines (hyperechoic), pale surface
Short axis—circular structure with pale halo (tendon sheath)
Internal architecture hyperechoic (semi-bright) dots (tendon fibrils) loosely packed, within hypoechoic
(darkened) surroundings—‘granular appearance’
Anisotropic ++

29. SONOGRAPHIC APPEARANCES
Tissue US appearance
Nerve
Fascicular
appearance
Long axis—tubular structures: bright surface. Internal architecture multiple broken bright
(hyperechoic) lines
Short axis—circular structure with bright surface (epineurium).
Internal architecture multiple hypoechoic black dots (nerve fascicles) with bright outlines within bright
surroundings (connective tissue, perineurium). ‘Speckled appearance’. Appearance varies between
proximal and distal peripheral nerves (see text)
Anisotropic +
Pleura Hyperechoic lines—‘sliding lung sign’ with respiration
Lung Normal lung is air filled and therefore not seen, generally characterized by its lack of distinct detail.
Reverberation artefacts from pleura (A lines) can be seen.
Bones
Periosteum
Cortex and
medulla
Hyperechoic line ++
Anechoic—black (due to reflection of the majority of the US beam from the periosteum, ‘drop out’
artefact below)

30. SONOGRAPHIC APPEARANCE
OF TISSUES
• Muscle (MU)
• Muscle appears hypoechoic (A and B). The perimysium, the connective tissue
surrounding individual muscle fascicles, appears hyperechoic.
• A muscle can be identified by moving joints that contract or relax the muscle.
• During a contraction, the muscle will thicken. Muscles can also be traced to their
attachments to help with identification.
• Myofascia (MY)
• Myofascia appears as hyperechoic layers (B). The hyperechoic appearance of
myofascia makes it easy to delineate muscles.
• Nerve
• Nerves appear medium gray with a heterogeneous texture.
• In long axis, they have a striated appearance due to their fascicular structure (C).
• In short axis, nerves have a characteristic honeycomb appearance (B).
• Hyaline cartilage (HC)
• Hyaline cartilage appears hypoechoic (A).

31. SONOGRAPHIC APPEARANCE
OF TISSUES
• Subcutaneous fat (Sf)
• Subcutaneous fat appears hypoechoic with characteristic interposed curved
hyperechoic lines that are formed by connective tissue septa (E). Fat
scatters ultrasonic waves, which can diminish the image quality of deeper
structures.
• Tendon (TE)
• Tendons appear hyperechoic (light) and in long axis, are striated (G).
• Fibrocartilage
• Fibrocartilage appears hyperechoic and has a homogeneous texture (D).
• Bone
• The surface of bone (the cortex) appears highly echogenic due to the large
difference in acoustic impedance between the overlying soft tissue and the
bone itself (D).
• Since most ultrasonic waves are reflected back to the surface, underlying
bone is devoid of signal.

32. APPEARANCE OF TISSUES
• Blood vessels (BV)
• The lumen of blood vessels appears anechoic (black), which contrasts with the hyperechoic wall
(F).
• Generally, arteries are smaller than veins and have a thicker wall. It is sometimes possible to
observe the valves within veins.
• Ligaments (Li)
• Ligaments appear hyperechoic and in long axis, have a laminar appearance (D). They are more
compact than tendons.
• Glands (Gla)
• Glands appear a mid-gray color and have a homogeneous texture (F).
• Fat within glands appears hyperechoic and can suppress transmission deeper into the gland.
• Air
• Air appears anechoic.
• Air between the transducer and skin will cause shadowing through the image.
• Fluid
• Fluid appears anechoic.

33. ANISOTROPY
• Isotropic means equal in all directions.
• Anisotropic implies angle dependence.
• The latter term has been used to indicate the
change in amplitude of received echoes from a
structure when the angle of insonation is
changed.
• Anisotropy is a discriminating feature between
nerves and tendons.
• Tendons are more anisotropic than nerves,
meaning that smaller changes in angle (about 2
degrees) alter the echoes from tendons than
the changes in angle (about 10 degrees) that
alter the echoes from nerves.
Anisotropy of the median nerve (A and B).
With inclination of the transducer (tilting), the received
echoes from the median nerve disappear.

34. PERIPHERAL NERVES
• Identification of peripheral nerves is not always easy.
• Knowledge of their distinguishing features is important.
• Nerves can be round, oval, triangular, or even flattened in shape.
• Along the course of a single nerve all shapes can be seen as the nerve passes
between adjacent structures.
• The larger peripheral nerves demonstrate a ‘fascicular’ or ‘honeycomb’ pattern.
• In general the more proximal the peripheral nerve the more hypoechoic its
appearance, becoming more hyperechoic as it moves distally.

35. APPEARANCE OF NERVES IN ULTRASONOGRAPHY
• On analyzing a histological
illustration of a peripheral nerve,
the epineurium, perineurium,
connective tissue, and neurons
are visible.
• By using high-frequency
ultrasound, the visualization of
all these structures is possible
Histological and corresponding ultrasound illustration of a peripheral nerve.
White arrow: epineurium; blue arrow: perineurium; yellow arrow: endoneurium.

36. • The arrow indicates a hypoechoic
central nerve structure (C5 root in
the interscalene space) with a
hyperechoic border in the area of
the interscalene groove.
• Tracking of this nerve structure in a
proximal and distal direction is
possible and is an important
method of identification.

37. • The arrow indicates a
hyperechoic peripheral nerve
structure (ulnar nerve at the level
of the lower third of the forearm).
• Tracking of this nerve structure
in a proximal and distal direction
is possible and is an important
method of identification.

38. • Longitudinal view of a peripheral
nerve.

39. Typical form of the ulnar nerve at three different anatomical positions.
• Above the elbow joint: oval;
• proximal third of the forearm: triangular;
• distal third of the forearm: round.

40. • Round shape of a peripheral
nerve (tibial nerve at the
popliteal level).

41. STRATEGIES WHEN NERVES ARE NOT VISIBLE
• For certain techniques, nerve
structures are not (always) directly
visible under ultrasound guidance:
• Intercostal.
• Paravertebral.
• Psoas compartment.
• Rectus sheath.
• Transversus abdominis plane (TAP).
• The reasons for the impaired or
even impossible direct ultrasound
visualization of nerve structures
with the above techniques are
mainly related to :
• The small dimension of nerves,
• large overlying muscle masses, or
• overlying bones.

42. ARTEFACT
• An artefact is any feature in an image that is not a true or accurate one-to one depiction of
the target being imaged.
• Because US imaging is formed by interrogating tissue with pulses of sound and detecting
echoes that may travel on a long complex path through the intervening tissue, US images are
subject to a number of artefacts.
• The user must understand how these are formed and learn to recognize them in order not to
misinterpret the images.
• Correct diagnosis comes through understanding the physical processes involved, correctly
driving the scanner, and a good knowledge of the anatomy being examined.

43. ARTEFACT
Contact artefacts
• Where shadowing or lack of image
appears from the top of the image,
it indicates a contact problem
between the probe and the skin,
e.g. a hollow curved surface of the
skin, lack of gel on skin, or at worst
a faulty transducer

44. ARTEFACT
Acoustic shadowing
• When an acoustically opaque target appears in the line of the US
beam, e.g. bone, calcification, or a vessel wall viewed edgeways on
no US will reach any distal targets and a dark shadow will appear
deep to the obscuring target on the image.
• In the case of calcification, this, together with a bright reflection from
the proximal surface, can be diagnostic.

45. ARTEFACT
US showing postcystic enhancement
and lateral wall shadowing. White
triangle, carotid artery; Black arrow,
post cystic enhancement; White arrow,
lateral wall shadowing.
US showing acoustic
shadowing. Black arrow,
surface of rib; White shadow,
acoustic shadow deep to rib;
Black dots, pleura.

46. ARTEFACT
Reflection artefacts
• Some anatomical structures have a large
smooth surface and can act as ‘mirror’
reflectors of US (e.g. diaphragm, bone,
pleural).
• A 2nd or reflected image then appears in a
place on the image where anatomically it is
unlikely to be.
• For example, on colour Doppler over the
clavicular region, a 2nd image of the
subclavian artery is seen in the lungs. US showing reflection artefact. Black arrow,
subclavian artery; White arrow, reflection of
subclavian artery below pleura; Black dots,
pleura.

47. ARTEFACT
Reverberation
• Reverberations occur as the result of US
waves bouncing back and forth between
2 strongly specular reflectors.
• The result is usually multiple linear and
hyperechoic areas distal to the reflecting
structures.
• In regional anaesthesia this
predominantly occurs between the
needle and probe surface, especially
when the needle is perpendicular to the
US beam
US showing reverberation artefact from a needle,
seen as a series of white parallel lines deep to the
needle reflection. White arrow, needle; Black
arrows, reverberations/multiple reflection artefact of
the needle.

48. ARTEFACT
Refraction artefacts
• differences in speed of sound may cause the
beam to be bent by refraction at large
interfaces with different speeds of sound on
either side.
• In regional anaesthesia this is commonly seen
as a ‘bent ‘needle as it passes through 2
tissues of different acoustic impedance (e.g.
fat and muscle).
• This has been termed the ‘Bayonet artefact’ Refraction artefact, seen as a bent needle as it passes
through 2 areas with slightly different acoustic impedance;
‘bayonet artefact’. White arrow, apparent step in needle
contour due to ‘Bayonet artefact’.

49. INTERROGATION
Along with tissue pattern recognition there are various methods of interrogating a structure to aid its
identification:
• Compressibility with the US probe.
• Pulsation.
• Valsalva: aids identification of the large veins in the neck and femoral vessels.
• Artefact effect: anisotropy with nerves and tendons. Post-cystic enhancement with a fluid-filled space.
• Doppler: nerves are often accompanied by vessels. With larger nerves this relationship is usually
consistent; however, considerable anatomical variation may be present with smaller nerves. Colour flow
will identify flow away from the probe as blue, and towards as red. Blue away, red towards: ‘BART’.
• Tracing structures: tendons may resemble peripheral nerves, similar in size, shape and their anisotropic
nature. Follow their course, tendons change their cross-sectional area and end in muscle or bone. Nerves
are relatively uniform along their length.

50. COLOR DOPPLER
a) When a sound wave is emitted from the transducer and reflected from a target object
moving toward the transducer, the returning frequency will be higher than the original
emitted sound wave. The corresponding image on the ultrasound machine is represented by
a red color.
b) Conversely, if the target object is moving away from the transducer, the returning frequency
will be lower than the original emitted sound wave. The corresponding image on the
ultrasound machine is represented by a blue color.

51. COLOR DOPPLER. SHORT AXIS VIEW OF THE
RADIAL ARTERY.
A. NO FLOW IS APPARENT WHEN THE BEAM
IS PERPENDICULAR TO THE DIRECTION IN
WHICH BLOOD IS FLOWING.
B. ADJUSTING THE TILT OF THE PROBE
ALTERS THE ANGLE OF INSONATION, AND
CONSEQUENTLY DISPLAYS BLOOD FLOW.

52. NEEDLING TECHNIQUES
• Good technique is based on a background of a good understanding of
the relevant anatomy and repetitive hands-on practice.
• Never advance a needle unless you can identify its tip at all times. If
the needle tip cannot be seen with certainty, then withdraw the needle
and start again.

53. THE APPROACH TO INSERT THE NEEDLE IS DESCRIBED
ACCORDING TO THE ORIENTATION OF NEEDLE TO THE PLANE OF
ULTRASOUND BEAM

54. SCANNING TECHNIQUE - LOCALIZATION
• Needle Tip
Finding the needle tip during ultrasound guided nerve block can be
technically challenging → particularly with the out of plane needle insertion
1. Transducer Movement to Locate the Needle Tip During Out of Plane
Needle Insertion.
2. Hydro Location Technique
3. Echogenic Needle

55. IN PLANE APPROACH - IP
IP position of the needle relative to
the ultrasound probe.
Improved visibility of the body of the needle
during a flat (left side) vs
a steep (right side) angle when the IP
technique is performed.

56. IN PLANE APPROACH
Recent evolutions in needle design allow
better visibility for steep angles during the IP
needle guidance technique.
Reverberation artefacts during the IP
technique can be avoided by slight lateral
movement of the needle relative to the probe.

57. OUT OF PLANE APPROACH - OOP
OOP position of the needle relative
to the ultrasound probe.
Ultrasonographic appearance of the tip of the
needle (arrow) when the OOP technique is
used.

58. OUT OF PLANE APPROACH - OOP
• Improved appearance of the tip
of the needle during a steep (left
side) compared with a flat (right
side) angle when the OOP
technique is performed.

59. NEEDLE TIP
1. TRANSDUCER MOVEMENT TO LOCATE THE NEEDLE TIP
DURING OUT OF PLANE NEEDLE INSERTION
A. The needle is inserted out of plane with
the transducer.
• The needle image is not seen because: The
transducer is still far away from the needle
thus the beam is not crossing the needle or
• The beam hitting the needle is deflected
away from the transducer and not returning
to the transducer because of the angle of
incidence (less than 90 degrees)

60. NEEDLE TIP
1. TRANSDUCER MOVEMENT TO LOCATE THE NEEDLE TIP
DURING OUT OF PLANE NEEDLE INSERTION
B. Maneuver # 1:
• Tilt the needle tip to a more superficial
position by decreasing the angle of insertion
(blue arrow, i.e., dropping the hand); this will
bring the needle and the beam closer to a 90
degree angle of incidence.
• It is also useful to wiggle the needle tip from
side to side or slightly in and out (a small
jabbing movement) until the needle is seen
(white arrowhead showing the needle shaft).

61. NEEDLE TIP
1. TRANSDUCER MOVEMENT TO LOCATE THE NEEDLE TIP
DURING OUT OF PLANE NEEDLE INSERTION
C. Maneuver # 2:
• To find the needle tip, it is important to move the
transducer towards the needle tip and then away from
the needle tip.
• This scanning movement will determine whether the
observed bright dot is the shaft or the tip of the needle.
• The needle tip is indicated by a white dot that is deepest
in the tissue (white arrowhead).
• The dot will disappear once the transducer is no longer
over the needle tip.

62. NEEDLE TIP
2. HYDRO LOCATION TECHNIQUE
• It can be technically challenging to locate the needle tip when the needle is
inserted at a steep angle (> 45 degrees) and when the target is > 4-5 cm deep.
• Injection of a small amount of fluid (0.5-1 mL) through the needle will create an
image of tissue expansion on ultrasound. This will indicate the location of the
needle tip.
• Dextrose 5% solution (a non conducting medium) is injected if electrical stimulation
is desired for nerve confirmation.
• Alternatively, saline or local anesthetic (conducting medium) can be injected if
nerve stimulation is not required.

63. NEEDLE TIP
2. HYDRO LOCATION TECHNIQUE
Figure A = pre-injection
Arrowhead = nerve
AA and AV = axillary artery and vein
PMM and PMiM = pectoralis major
and minor muscles
Figure B = needle tip is within PMiM as
indicated by local tissue expansion (asterisk *)
Arrowhead = nerve
AA and AV = axillary artery and vein
PMM and PMiM = pectoralis major and minor
muscles
Figure C = needle tip is now deep to PMiM and
anterior to AA as indicated by local fluid expansion
(asterisk*) although the tip is not visualized
Arrowhead = nerve
AA and AV = axillary artery and vein
PMM and PMiM = pectoralis major and minor
muscles

64. NEEDLE TIP
3. ECHOGENIC NEEDLE
• It is easier to detect a needle with
an echogenic tip. The figure shows
an example of the echogenic tip
needle (Hakko™ Medical Co. LTD
Japan) with 3 hyperechoic dots at
the needle tip (arrows).

65. GOLDEN RULES OF US-GUIDED REGIONAL
ANAESTHESIA AND PAIN MANAGEMENT
• Never advance the needle unless you can identify the needle tip at all times.
• Never deliberately contact the nerve. Place the needle next to the nerve.
• Observe injection. If unable to see spread of LA consider intravascular
injection or needle tip not in scan plane.
• Injection should be resistance free and painless. If not, stop, reposition needle.
• If the nerve swells on injection, stop, consider intraneural injection.

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