Focused thoracic ultrasound

+

Focused Thoracic Ultrasound

Sonographic appearances of the normal thorax

Dr Andrew Ferguson

Consultant in Intensive Care Medicine & Anaesthesia

+A shot in the dark…

simply a hopeful

attempt to hit an enemy

that you can't see

+Why Use Thoracic Ultrasound?

Increasingly “standard of care” issue

Stop “shooting in the dark”

Both for Seldinger and conventional “surgical” drains

Really informative – negative findings also important

Interesting and challenging

Enjoyable!

+Objectives

Level 1 sono-anatomy

Right and left hemidiaphragm

Ribs and intercostal spaces

Lungs

Heart

Liver, spleen, kidneys

+Diaphragm

Double or triple line

Easily seen in presence of effusion from mid-axillary line

Abdominal surface visible with ascites

Curves upwards except with large effusions

Closely applied to liver/spleen – used as acoustic windows

Functional assessment feasible

+Diaphragm

Boussuges A et al. Chest 2009;135:391-400

C

+Diaphragm (trans-organ)

RIGHT through liver LEFT through spleen

+Diaphragm Function (M-Mode)

RIGHT

LEFT

Towards probe

+Diaphragm Function (2-D)

Normal diaphragm thickens on inspiration

End-inspiratory thickness 20% or more above baseline

+Heart

+Liver

Note texture (remember for consolidated lung images)

Artifacts e.g. mirror-image (implies aerated lung above)

Liver

Mirror-image

Liver

Diaphragm

Kidney

Hepato-renal recess

+Spleen

Diaphragm

Spleen

Kidney

Spleno-renal recess

+Intercostal space

Pleura

+Lungs – normal static findings

Normal lung considered “invisible” to ultrasonographer

Artefacts can be used to infer normality or abnormality

A lines

horizontal reverberation artifacts from pleural line

the only finding in 2/3 of normal lung US

B lines

vertical narrow bands from pleural line to edge of screen

obliterate the A line

multiple B lines = Ultrasound Lung Rockets = interstitial oedema

Abnormal lung has characteristics that are clinically useful

+Lungs – normal static findings

Rib

B line

Wipe out A lines as they pass

A lines

“Bat sign”

Rib Rib

+Lungs – normal dynamic findings 1

Pleural sliding (lung sliding sign)

Pleural line “shimmers” with respiration

Presence of lung sliding rules out pneumothorax

Lung sliding greatest in lower thorax (greatest expansion)

Absence of lung sliding has a number of causes

Pneumothorax

Apnoea

Pleural adhesions

Mainstem bronchial intubation or occlusion

Critical parenchymal lung disease e.g. ARDS, contusion

+Lung sliding

+Lungs – normal dynamic findings 2

M-mode “seashore sign”

Structures superficial to pleural line are static

= Horizontal lines on M-mode (motion against time) = WAVES

Motion of pleural line is “reflected” deep to it

= Granular pattern reflecting motion = SAND

+M-Mode seashore sign

Pleural line

Static structures

horizontal lines (waves)

Pleural line reverberations

dynamic – granular (sand)

+Lungs – normal dynamic findings 3

“Lung pulse” sign

Cardiac pulsations transmitted via lung to pleura

When seen in the absence of sliding…

Normal if breath-hold

Abnormal in other conditions with no sliding

Presence of lung pulse excludes pneumothorax

+Lung Pulse Sign

+

Focused Thoracic Ultrasound

Sonographic appearances of the abnormal thorax

Dr Andrew Ferguson

Consultant in Intensive Care Medicine & Anaesthesia

+Objectives – Level 1

1. Pleural effusion

2. Pleural thickening

3. Consolidated lung

4. Paralysed hemidiaphragm

5. Pericardial effusion

6. Pneumothorax

7. Interstitial syndrome

8. Guided thoracocentesis and drain placement

+Pleural effusion

Characteristics

Anechoic (transudate or exudate)

Echoic

Homogeneously echogenic

Complex non-septated (exudate)

Complex septated (exudate)

Size

Depth on 2-D

Estimates of volume

Inversion of diaphragm if very large

+Pleural effusion - anechoic

+Pleural effusion, complex, non-septated

Plankton sign –

mobile swirling

elements in

effusion

+Pleural effusion, complex, septated

+Pleural effusion, inverted diaphragm

+Effusion with atelectasis

+Clotted haemothorax

Clot

Lung with peripheral

consolidation

(contusion)

+Organised Haemothorax

+Pleural effusion - colour doppler

Fluid colour sign – can be used to differentiate small

effusion from pleural thickening

+Fluid colour sign

Kalokairinou-Motogna M, et al. Medical

Ultrasonography 2010, Vol. 12, no. 1, 12-16

+Pleural thickening

Hypo-echoic pleural plaque

+Malignant pleural thickening

+Lung consolidation

Tissue pattern

loss of air barrier leading to a “real” tissue image akin to liver i.e.

hepatisation

Boundary or shred line

ragged boundary between consolidated and normal lung

Air bronchograms

Non-mobile linear or punctate hyper-echoic features

Fluid bronchograms

May be partially fluid-filled with material motion visible with breathing

+Lung consolidation

+Lung tail (atelectasis and consolidation)

Note normal thickening of diaphragm with inspiration

+Lung consolidation

Note material within effusion

+Severe consolidation - hepatisation

Hepatised lung

Fluid bronchograms

+Pneumothorax

Absent lung sliding

Absent lung pulse

Absent lung rockets

M-Mode – barcode or stratosphere sign

Lung-point sign

+Pneumothorax – stratosphere sign

+Pneumothorax – lung point sign

+Pneumothorax – lung point sign

1) Transient normal

pattern as lung

reaches chest wall

at peak inflation or

2) transition zone

where lung is sitting

on chest wall

+Lung point on 2D US

+Interstitial/alveolar syndrome

Interlobular septal thickening/oedema

> 3 lung rockets spaced around 7mm apart (B7 lines)

Alveolar filling/oedema

> 3 lung rockets spaced around 3mm apart (B3 lines)

Lichtenstein DA, et al. Chest 2009;136:1014-1020

B7 B3Normal

+Diaphragm Dysfunction (M-Mode)

Towards probe

Normal Paralysis

+Diaphragm Dysfunction (2-D)

Towards probe

NO thickening

McCool FD, Tzelepis GE. Dysfunction of the Diaphragm. N Engl J Med 2012; 366:932-942

+Pericardial effusion

Combined pleural and pericardial effusions

Pericardial effusion

+Pneumothorax US algorithm

Lung

sliding

YES

No pneumothorax

NO

B-lines

YES

NO

Lung

point

Lung

pulse

NO

YES

YES

NO

Pneumothorax