chest ultrasonograhy techanical aspects and interpretation
TRANSCRIPT
Chest Ultrasonograhy :Technical
Aspects and Interpretation
Gamal Rabie Agmy ,MD ,FCCP
Professor of Chest Diseases, Assiut University
ERS National Delegate of Egypt
Basics
• U/S probes emit and
receive the energy as
waves to form pictures
Ultrasound Transducer
Speaker
transmits sound pulses
Microphone
receives echoes
• Acts as both speaker & microphone Emits very short sound pulse
Listens a very long time for returning echoes
• Can only do one at a time
Physical Principles
Cycle • 1 Cycle = 1 repetitive periodic oscillation
Cycle
Frequency
• # of cycles per second
• Measured in Hertz (Hz)
-Human Hearing 20 - 20,000 Hz
-Ultrasound > 20,000 Hz
-Diagnostic Ultrasound 2.5 to 10
MHz
(this is what we use!)
frequency 1 cycle in 1 second = 1Hz
1 second
= 1 Hertz
High Frequency
• High frequency (5-10 MHz)
greater resolution
less penetration
• Shallow structures
Low Frequency
• Low frequency (2-3.5 MHz)
greater penetration
less resolution
• Deep structures
Probes
A common language: Color Coding
Black Grey White
Ultrasound profiles.
Lichtenstein D A , Mezière G A Chest 2008;134:117-125
Normal lung surface
Left panel: Pleural line and A line (real-time). The pleural line is located 0.5 cm below the rib line in the adult. Its visible length between two ribs in the longitudinal scan is approximately 2 cm. The upper rib, pleural line, and lower rib (vertical arrows) outline a characteristic pattern called the bat sign.
Scanning Positions for Chest Sonography in ICU
Normal Anatomy
Tissue pattern representative of Alveolar
Consolidation
Presence of hyperechoic punctiform images representative of air bronchograms
Pleural
effusion
Lower lobe
the "seashore sign" (Fig.3).
Absent lung sliding
Exaggerated horizontal artifacts
Loss of comet-tail artifacts
Broadening of the pleural line to a band
Lung point
Loss of lung pulse
The key sonographic signs
of Pneumothorax
the "seashore sign" (Fig.3).
Pulmonary Embolism
Schematic representation of the parenchymal, pleural and vascular
features associated with pulmonary embolism.(Angelika Reissig, Claus
Kroegel. Respiration 2003;70:441-452 )
Alveolar-interstitial syndrome
Multiple B-lines - « comet-tails » - interstitial edema (B1)
7 mm apart « B lines » thickened interlobular septa
D Lichtenstein et al AJRCCM 156 : 1640-1646 , 1997 JJR 25 05 2012
http://www.reapitie-
univparis6.aphp.fr http://www.reapitie-
univparis6.aphp.fr
02 09 2012
D Lichtenstein et al AJRCCM 156 : 1640-1646 , 1997 30 11 2011
Coalescent B lines - « comet-tails » - alveolar
edema
3 mm apart « B lines » ground-glass areas
http://www.reapitie-
univparis6.aphp.fr
02 09 2012
(Chest. 2008; 133:836-837)
© 2008 American College of Chest Physicians
Ultrasound: The Pulmonologist’s New Best
Friend
Momen M. Wahidi, MD, FCCP
Durham, NC
Director, Interventional Pulmonology, Duke
University Medical Center, Box 3683, Durham,
NC 27710
