Sonographic features of pneumothorax dr suresh

SONOGRAPHIC DIAGNOSIS OF PNEUMOTHORAX

1. DR SURESH A ASSOCIATE PROFESSOR DEPARTMENT OF RADIOLOGY VIMS& RC SONOGRAPHIC DIAGNOSIS OF PNEUMOTHORAX

2. Introduction Thoracic sonography is a rapidly evolving imaging modality of choice for lung imaging. Lung sonography is made possible by the interpretation of ultrasound artifacts, caused secondary to confinement of air between the lung and chest wall, that prevents diffusion of the ultrasound beam into the parietal pleura and deep lung structures. Bedside ultrasound of the lung has an established role in the diagnosis of thoracic diseases.

3. Probe selection L inear array high frequency probe (5-13 MHz) To analyze superficial structures such as the pleural line and providing better resolution. C urvilinear array probe (1-8 MHz)  More suitable in imaging deeper lung structures as it provides better penetration at the cost of less resolution. Phased array probe (2-8 MHz)  Flat and smaller footprint is better suited for imaging between the ribs; commonly used in cardiac imaging.

4. Technique Patients are scanned in supine/Erect position. The probe is placed in sagittal position on the anterior chest wall – 2 nd intercostal space in the mid-clavicular line The sonographer should identify the landmarks of two ribs with posterior shadowing behind them and visualize the plaueral line in between them  Bat Sign Periosteum of ribs represent the wings and the hyperechoic pleural line between represent the bats body In between the two ribs, the two pleural layers are seen sliding across. BAT SIGN

5. TECHNIQUE Pneumothorax contains air and no fluid, hence it will rise to the anterior and least dependent area of the chest. As the patients are commonly supine, this area corresponds to the anterior region of the chest at the 2 nd to 4 th intercostal spaces in the mid-clavicular line. Hence, this is the recommended initial area for investigation in trauma cases If the patient is upright, air accumulates in apicolateral location

6. sagittal scan depicting normal anatomy

7. pneumothorax Pneumothorax: refers to the presence of gas (air) in the pleural space. It is useful to divide pneumothoraces into three categories 1)Primary spontaneous: No underlying lung disease 2)Secondary spontaneous: U nderlying lung disease is present 3)Iatrogenic/traumatic Traumatic - Commonly associated with both blunt and penetrating chest injuries.

8. Chest Ultrasound Tips First get oriented to the machine Next get oriented to the patient Find something that you recognize (it probably wont be the lung at first ) Navigate from there Confirm normal findings S eek and explore abnormal findings

9. Advantages of Ultrasound Performed at bedside without delays No radiation or contrast exposure Repeatable with serial assessment Detects and localizes pathology Guides procedures

10. Disadvantages of Ultrasound Operator dependent Confusing artefacts Training requirements

11. NORMAL LUNG FINDINGS IN THORACIC ULTRASOUND BATWING SIGN PLEURAL LINE SLIDING LUNG A LINES AND B LINES LUNG PULSE POWER/ DOPPLER SLIDE SIGN

12. PLEURAL LINE/SLIDING SIGN : Most important finding in normal aerated lung Sonographer visualizes the hyperechoic pleural line in between two ribs moving back and forth Lung sliding corresponds to the to and fro movement of the visceral pleural on the parietal pleura occuring with respiration. Two different patterns are displayed: motionless portion above the pleural line – Horizontal waves Sliding below the pleural line – granular pattern (sand) in M mode. The resulting picture resembles waves crashing onto the sand – Seashore sign (indicating normal aerated lung)

13. BAT WING SIGN

14. PLEURAL LINE/SLIDING SIGN

15. SEA SHORE SIGN (m mode)

16. B-LINES OR COMET-TAIL ARTIFACTS: are reverberation artifacts appearing as hyper echoic vertical lines that extend from the pleura to the edge of the screen. Comet-tail artifacts move with lung sliding and respiratory movements These artifacts are seen in normal lung due to acoustic impedance differences between the water and air Excessive “B-lines” on the other hand may be abnormal – indicating interstitial edema

17. A-lines A-lines are a type of reverberation artifact, equally spaced, horizontal lines originating from the hyperechoic pleural line. In normal lung, B-lines extend out and erase the “A-lines”

18. LUNG PULSE

19. Power Slide It refers to the use of power Doppler to help identify lung sliding. Power Doppler helps pick up subtle flow and movement. If lung sliding is present, power Doppler will light up the sliding pleural line with color flow.

20. LUNG FINDINGS IN PNEUMOTHORAX ABSENT LUNG SLIDING SIGN LOSS OF COMET-TAIL ARTIFACTS BROADENING OF THE PLEURAL LINE TO A BAND LUNG POINT OR TRANSITION POINT CHANGE FROM SEASHORE TO (STRATOSPHERE OR BAR CODE SIGN IN M MODE)

21. Lung SLIDING SIGN

22. Presence of sliding effectively rules out pneumothorax. The absence of lung sliding does not necessarily indicate that a pneumothorax is present. Lung sliding can also be abolished in other conditions like acute respiratory distress syndrome, pulmonary fibrosis, large consolidations, pleural adhesions, atelectasis, right main stem bronchus intubation, phrenic nerve paralysis

23. Lung Point in Pneumothorax Pneumothorax Lung point LUNG POINT DEMONSTRATED ON CT AND ON ULTRASOUND

24. EVALUATION OF PNEUMOTHORAX BY M-mode SEA SHORE SIGN BAR CODE SIGN

25. Comet tail artifacts / B-lines In pneumothorax, ultrasound demonstrates the loss of “comet tail artifacts. These artifacts are lost due to air accumulating within the pleural space causing reduction in the propagation of sound waves and eliminating the acoustic impedance gradient. As comet tail artifacts are generated by the visceral pleura, and this pleura is not visualized in a pneumothorax, the artifacts are not generated. The visualization of even one comet-tail essentially rules out the diagnosis of a pneumothorax

26. A-lines “ A-lines” are thoracic artifacts that help in the diagnosis of pneumothorax. The space between each A-line corresponds to the same distance between the skin surface and the parietal pleura. In the normal patient, B lines extend from the pleural line and erase the A lines “A-lines” will be present in a patient with pneumothorax but “B-lines” will not be seen. If lung sliding is absent with the presence of “A-lines” the sensitivity and specificity for occult pneumothorax is 95 and 94 % respectively

27. Lung-point sign Lung-point sign – occurs at the border of a pneumothorax. Helpful in determining the actual size of the pneumothorax This sign can be delineated using M-mode where alternating “seashore” and “stratosphere” patterns are depicted over time “lung-point sign” is 100% specific for pneumothorax and defines its border If the lung-point sign is identified in a location more posterior or lateral, the larger the pneumothorax. The determination of the size of a pneumothorax is important, as larger pneumothoraces are likely to require thoracostomy.

28. Lung Pulse Rhythmic movement of the pleura in synchrony with the cardiac rhythm. Best viewed in areas of the lung adjacent to the heart – at the pleural line. A result of cardiac vibrations transmitted to the lung pleura in poorly aerated lung Cardiac activity is essentially detected at the pleural line – when there is absent lung sliding in certain conditions.

29. Algorithm for the ultrasound diagnosis of pneumothorax

30. CONCLUSION Thoracic sonography of has become a well-established modality in the acute care setting for detection of pneumothorax. It is Indispensable in the blunt or penetrating chest trauma patient USG chest and AP radiograph are complementary to eachother in diagnosing a pneumothorax. CT scan remains the gold standard and may still catch smaller occult pneumothoraces that ultrasound misses.

31. Thanks for your attention!