Thoracic surgical radiology

Thoracic

Thoracic surgical radiologyrachel hyland

hilary Moss

Abstractchest radiographs of patients in the intensive care or postoperative set-

ting can be difficult to interpret. Postoperative complications may be life-

threatening and require prompt management. Knowledge of the diverse

radiological appearances of these complications as well as familiarity with

the clinical settings in which specific complications are likely to occur is vital

for prompt, effective treatment. Following pulmonary resection, patients

often have postoperative complications that differ according to the type

of surgery and the time elapsed since surgery was performed. This article

describes the potential complications and gives illustrated explanations of

normal postoperative appearances, for example following pneumonectomy,

as well as demonstrating important complications such as bronchopleural

fistula. The article highlights the differences in the appearance of the chest

radiograph of atelectasis and consolidation, with illustrated examples.

Keywords atelectasis; chest radiograph; complications of thoracic

surgery; consolidation; pneumonectomy; postoperative appearance

Collapse

Lungs or lobes of lungs collapse because of obstruction of the bronchus leading to the lobe or lung. The bronchus may become obstructed by something within the lumen such as a foreign body or a mucous plug, narrowing of the bronchial wall by, for example, a carcinoma or scarring from tuberculosis, or some-thing compressing the bronchus from outside the wall, such as a mediastinal lymph node mass.

There are two main signs seen on the plain radiograph (Figures 1–4). First, the collapsed lobe is more opaque than usual, as the same amount of lung parenchyma occupies a smaller vol-ume and there is retention of mucus within the lobe. In addition, there are signs of volume loss – direct signs with displacement of fissures, blood vessels and bronchi, and indirect signs where

Rachel Hyland, MBChB, FRCR, is a Specialist Registrar in Radiology on

the Leeds Training Scheme. She qualified from Sheffield in 1999, and

has been working in the Leeds Teaching Hospitals NHS Trust since

2002, with a specialist interest in cross-sectional imaging. Competing

interests: none declared.

Hilary Moss, MRCP, FRCR, is a Consultant Radiologist in Harrogate

and District NHS Foundation Trust. She trained in radiology in

Addenbrooke’s and Papworth hospitals, Cambridge, before becoming

a Consultant in the Leeds Teaching Hospitals NHS Trust from 1999 to

2005. Her specialist interests are thoracic and oncological imaging.

Competing interests: none declared.

aNaESThESia aND iNTENSiVE carE MEDiciNE 9:11 47

there is shift of other structures to compensate for the volume loss of the collapsed lobe. Indirect signs of volume loss include overexpansion of the adjacent lobe which therefore appears less dense than normal as it contains relatively more air with stretched parenchyma, elevation of the ipsilateral hemidiaphragm, tracheal or mediastinal shift and narrowing of the space between ribs.

Consolidation

Consolidation occurs when the air spaces are filled with cells (carcinoma), pus (pneumonia), blood (pulmonary haemor-rhage), fluid (inflammatory or cardiac failure) or protein (alve-olar proteinosis) rather than air. Consolidation (Figures 5–7)

Right upper lobe (RUL) collapse: frontal and lateral radiographs

a

b

a Increased density of RUL

• Rotates to lie against superior mediastinum at lung apex anteriorly

• Loss of borders of adjacent mediastinal structures such as superior

vena cava

b Signs of volume loss

• Major and minor fissures move upwards towards each other like a

closing book and rotate towards the mediastinum

• Fissures concave

• Upper hilar vessels disappear into collapsed lobe

• Shift of other structures to fill space:

– the lower lobe expands and appears more lucent and the lower lobe

artery and bronchus move out and up

– elevation of the diaphragm

Figure 1

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Thoracic

Left upper lobe (LUL) collapse

Increased density of LUL

• Collapses forwards, retains contact with anterior chest wall

• Hazy increased density extending from hilum

• Fades out laterally and inferiorly

• Loss of left diaphragm adjacent to cardiac apex

• Loss of outline of upper left hilum and left heart border

Signs of volume loss

• Left hilum elevated

• Left lower lobe expands so lower lobe artery and bronchus move out

and up

• Lucency adjacent to left heart border and at lung apex as the LUL reduces

further in volume and left lower lobe expands more

Figure 2

Right middle lobe (RML) collapse

Increased density of RML

• Lies anteriorly adjacent to right heart border, which therefore appears

ill-defined


• RML small so signs of volume loss are not usually major

• Movement of minor fissure downward

Figure 3


Left lower lobe (LLL) collapse

• Similar radiological features of lower lobe collapse on the left and the

right

Increased density of lower lobe

• Collapses posteriorly, inferiorly and medially

• Triangular density seen behind heart

• Loss of medial border hemidiaphragm

• Loss of border of descending thoracic aorta


• Major fissure rotates backwards and medially

• Upper part of major fissure swings downwards

• Hilum moves inferiorly

• Lower lobe vessel and bronchus move inferiorly and enter opaque lobe

• Right superior mediastinal displacement owing to right lower lobe

collapse

• Cardiac rotation: flat left heart border in LLL collapse

• Shift of mediastinum, elevation of hemidiaphragm to fill the space

Figure 4

Consolidation due to heart failure

Severe hypoxia postoperatively. Chest radiograph demonstrates typical

features of pulmonary oedema with predominantly perihilar consolidation

with loss of the outline of vessels and the presence of air bronchograms

Figure 5

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Thoracic

appears as an area of increase in lung density which is ill defined except at a pleural margin such as a fissure. There is no volume loss with pure consolidation; in fact, there may be an increase in the volume of the lobe. Normal vessels are not seen as they are no longer surrounded by contrasting air. Air bronchograms which are seen as branching linear lucencies may be seen in an area of consolidation and are due to air present in normal bron-chi which is now contrasted against the increased density of the filled airspaces. Signs of consolidation localize an abnormality to the pulmonary parenchyma.

Thoracic surgery: pneumonectomy and its complications

Complications following pneumonectomy may be classified as early or late (Table 1). Sequential chest radiographs are used to screen for these complications in the early postoperative period (Figure 8).

Bronchopleural fistula

Bronchopleural fistula (BPF) occurs when there is a communica-tion between the airway and the pleural space and is a poten-tially fatal complication of pneumonectomy. The incidence is reported to be up to 9%,1 with an associated mortality rate of 16–23%,2 usually due to aspiration pneumonia with subsequent acute respiratory distress syndrome.3 A BPF is more likely to occur after right pneumonectomy than after left pneumonec-tomy.2,3 In the early postoperative period the aetiology is usu-ally either infection or operative technique. Late development of a BPF is most likely due to local recurrence at the bronchial stump. As there is a communication between the airway and the pleural space there is an increase in or reappearance of air in the pneumonectomy space and so it is important to monitor changes in the air–fluid level in patients who have undergone a pneumo-nectomy.4 The features of BPF on chest radiograph are shown in Table 2 and Figure 9.

Lingular consolidation due to postoperative infection

Ill-defined consolidation is effacing the left heart border

Figure 6


Thoracic complications of pneumonectomy

Early Late

Pulmonary oedema recurrent disease

acute respiratory distress

syndrome

Empyema

Pneumonia of contralateral

lung

complication associated with

radiotherapy or chemotherapy

Bronchopleural fistula Late-onset fistula (broncho- or

oesophagopleural)

Post-pneumonectomy syndrome

Table 1

Consolidation due to alveolar cell carcinoma

a

b

Patient presented with cough productive of green sputum, malaise. a Chest

radiograph showed consolidation in the right lower zone through which the

heart border can be seen as well defined, placing the consolidation in the

right lower lobe. Chest infection diagnosed and treated. Follow-up chest

radiograph 8 weeks later not significantly changed although patient felt a

little better. b Computerized tomography demonstrates consolidation of the

right lower lobe with anterior bulging of the fissure showing increased

volume of the lobe. Bronchoscopy confirmed alveolar carcinoma. It is

important that all abnormal chest radiographs are followed up

Figure 7


Thoracic

Left pneumonectomy for adenocarcinoma

a

b

c

Normal postoperative chest radiograph appearances in a 62-year-old woman

who underwent left pneumonectomy for adenocarcinoma.

a Radiograph immediately after operation shows left-sided chest drain with

air in the post-pneumonectomy space, a midline trachea and some mild

congestion of the right lung. b Radiograph on postoperative day 2 shows

fluid in the lower post-pneumonectomy space and reduction of volume

of the left hemithorax with elevation of the left hemidiaphragm as shown

by the elevated gastric bubble. c Radiograph 2 months later showing

complete filling in of the pneumonectomy space. The fluid component in

the pneumonectomy space gradually increases and the air component

decreases until the space is fluid filled. The volume of the hemithorax

decreases with ipsilateral mediastinal shift, diaphragmatic elevation and

rib crowding. Obliteration of the air component is variable, but usually

occurs within weeks to months

Figure 8


Table 2

Features of bronchopleural fistula on chest radiograph

• Failure of the post-pneumonectomy space to fill

• Persistent or progressive pneumothorax despite adequate

tube drainage

• Progressive subcutaneous or mediastinal emphysema

• a 2 cm drop in the air–fluid level, with contralateral

mediastinal shift

• contralateral aspiration pneumonia because of a

transbronchial spill

• Sudden pneumothorax or reappearance of air in a previously

opaque postpneumonectomy space

Bronchopleural fistula

a

b

A 73-year-old man underwent right pneumonectomy for adenocarcinoma.

a Discharge film shown on postoperative day 12 with almost complete

resorption of air. b Patient presented 1 month later with a wound

infection and generally unwell. Radiograph shows the development of an

air–fluid level within the right hemithorax, and left basal consolidation

consistent with contralateral aspiration pneumonia. Bronchopleural fistula

was confirmed at surgery

Figure 9


Thoracic

Aortic dissection repair and mitral valve replacement

Immediate postoperative film shows left lower lobe collapse, pulmonary

oedema and widening of the mediastinum, which resolved on later film

Figure 10

Supine effusion in patient after sternotomy

Adequate position of endotracheal tube (5–7 cm above the carina), and

Swan–Ganz catheter (right lower pulmonary artery within 2 cm of the

mediastinum). There is a hazy increased density superimposed over the

right lower hemithorax, through which the normal bronchovascular

markings can be seen, with no air bronchograms or volume loss to suggest

consolidation or collapse. Other signs of a supine effusion include loss of

the normal silhouette of the diaphragm and blunting of the lateral

costophrenic angle (meniscus sign), with elevation of the level of the

apparent hemidiaphragm and an apical cap

Figure 11


Cardiac surgery

Lines and tubesThe central venous catheter tip should lie within the supe-rior vena cava or brachiocephalic veins. The tip should not be curved, as this may be because the catheter has snagged on the vessel wall or perforated the vessel. Complications of central venous catheter insertion include pneumothorax, haemothorax, mediastinal haematoma and pericardial tamponade.

An intra-aortic balloon pump tip should lie just below the aortic knuckle.

Post-sternotomyThere is a spectrum of acceptable appearances in the postop-erative cardiac patient. Frequent findings include left lower lobe collapse or basal atelectasis, transient pulmonary oedema (25%), small- or moderate-sized pleural effusions and increased medias-tinal size compared with the preoperative film due to periopera-tive haemorrhage (Figure 10).

Complications after sternotomy include persisting left lower lobe collapse, severe pulmonary oedema, significant pleural effu-sion appearing acutely (Figure 11) or after day 3 or 4 due to infec-tion or delayed bleeding and an enlarging mediastinum, implying a significant bleed. Delayed complications include Dressler’s syndrome and sternal infection. ◆

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2 © 2008 Elsevier Ltd. all rights reserved.

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Thoracic surgical radiology