Click on the button below to go to the main page:

Click on the button below to go to the previous page:

CONSOLIDATION

Like everything in lung US, the interpretation of findings requires a clinical context. As such, consolidation, may be due to pneumonia, malignancy, infarct or prolonged atelectasis. The appearance in each of these is similar with only subtle differences. Lung US is as accurate as CXR for the diagnosis of consolidation; however unlike CXR it can detect consolidation within an effusion and abscess formation within consolidation (1). Lichtenstein showed that 90% of pneumonic change begins at the pleura and so can be easily visualised with lung US at L4/R4 (2).

Consolidation on lung US appears hypoechoic and tissue like reflecting the hepatisation of lung with inflammatory debris. The presence of dynamic air bronchograms and vascularity on colour doppler are helpful in differentiating consolidation from collapse (3). Be aware that early on during the consolidation process, before alveoli fill with debris,  signs of disease may only be an irregular pleura and increased B lines. 

PNEUMONIA

Features of consolidation due to pneumonia are:

1. hypoechoic tissue-like lung

2. air bronchograms

3. colour doppler showing vessels

These changes are most obvious when there is lobar consolidation. When there is segmental consolidation, aerated (but nevertheless diseased) lung deep to the consolidation shows profuse B lines.  This sign is called the shred sign.

R4: lobar consolidation: hyperechoic (white) branching structures are air bronchograms.

R4: lobar consolidation with colour doppler showing vessels

Segmental consolidation showing a sub pleural hypoechoic area with B lines deep to this (shred sign)

MALIGNANCY

Malignancy may be identical to pneumonia on US. However sometimes due to bronchiolar obstruction, you may be able to see dilated fluid bronchograms.

Malignant consolidation with dilated bronchioles filled with fluid (anechoic linear structures)

ABSCESS

When abscesses form within consolidation, they will appear like fluid filled areas within the consolidation. Unlike a pleural effusion, the diseased lung will surround the fluid pocket and circumferentially decrease/increase its size with breathing instead of moving in and out of it with respiration. 

Abscess within consolidation. Central anechoic area is the abscess. Hypoechoic area is the consolidation.

Click on the button below to go back to the POCUS modules 

REFERENCES

1. Biagi C, Pierantoni L, Baldazzi M, et al. Lung ultrasound for the diagnosis of pneumonia in children with acute bronchiolitis. BMC Pulm Med. 2018;18(1):191.

2. Lichtenstein DA. Lung ultrasound in the critically ill. Ann Intensive Care. 2014 Jan 9;4(1):1. 

3.Haaksma ME, Smit JM, Heldeweg MLA, Nooitgedacht JS, de Grooth HJ, Jonkman AH, Girbes ARJ, Heunks L, Tuinman PR. Extended Lung Ultrasound to Differentiate Between Pneumonia and Atelectasis in Critically Ill Patients: A Diagnostic Accuracy Study. Crit Care Med. 2022 May 1;50(5):750-759