Basic Chest Radiology 2

Airspace shadowingNodes , nodules and masses

Air where it should not be!

The secondary pulmonary lobule• The smallest unit we can see on CT scans• 3 cm long• Best anatomical organisation in the lower lobe

Centrilobular Pulmonary arteries

Pulmonary veins and lymphatics

Septal lines and a lamellar effusion

Radiological signs of pulmonary oedema• Between 20-25 mmHg. PIE interstitial shadowing,

peribronchial cuffing. septal lines(Kerley Bs).overlaping Kerley As-reticular shadowing.

• The vessels become indistinct• Upper lobe blood diversion. Difficult to asses 3mm in 1st

intercostal space. Blood vessel larger than accompanying bronchus.

• Ground glass appearance/consolidation usually bilateral unless there is dependence or unilateral disease.

• Airspace shadowing can be pus ,fluid, blood and rarely tumour

Classic radiological consolidation

Diagnosis depends on history1.Oedema-cardiac or non cardiac2.Pneumonia3.Aspiration4.Haemorrhage5.Alveolitis for any cause

Lymph nodes• The axial diameters of lymph nodes goes as

one descends in the chest. From 1 cm in the paratracheal regions to 1.5cm in the subcarinal region.

• Look at hilar and right paratracheal regions. The right hilar drains right lung and at least the lower ½ of the left

1.Sarcoid-bilateral symmetrical2.TB-usuallY unilateral3.Lymphoma-usually bilateral asymmetrical4.Ca-usually unilateral5.Metastatic-unilateral or asymmetrical6.Fungal-unusual in UK

If in doubt use the surgical sieveSPN1.Primary tumour-malignant or benign2.Harmatoma3.granuloma-TB4.Solitary metastases5.Solitary AVM6.Round pneumonia7.Rond atelectasis

Solitary pulmonary nodule

• By definition a nodule measures less than 3 cm.• Lobulated (worse) or spiculated is bad.• Calcification is good. Needs to be central, uniform or

popcorn.• Crossing fissures is bad. • Very unlikely to be malignant in a non smoker.

• If a disease pattern is diffuse in the lungs, it is most apparent where there is most volume of lung-mid and lower zones and more centrally.

• Applies to interstitial desease,airspace disease and multiple nodules.

MULTIPLE NODULES

1.METASTASES 90%+2.RHEUMATOID NODULES-very rare in absence of clinical disease3.AVMs-may see feeding vessels4.Wegeners-isually cavitating5.Septic emboli-usually staph or strep6.Multiple granuloma-usually small with calcification.

• Can be difficult to see ,especially with underlying COPD.• The more dense the nodules the easier, it is to see them-

hence alveolar microlithiasis is easy to see.• Multiple calcified small nodules is almost always secondary to

old varicella pneumonia.• Pulmonary venous back pressure can cause small calcific

densities in the bases.• Miliary TB does not cause calcification

Micronodular disease

1.Miliary TB2.Atypical pneumonia3.Miliary metastases and Lymphoma4.3.Sarcoidosis5.Extrinsic allergic alveolitis(soft)

Pneumothorax

1. Look for a pleural line2. 2cm edge corresponds to 50% of volume3. Should always aim for an erect film4. There is no evidence that an expiratory

film is more sensitive5. Decubitus or lateral may be helpful6. Beware a tension pneumothorax,

mediastinal shift away and flattening of hemidiaphragm, increased pressure causes decreased venous return and death/compromise.

7. In the supine position look for a deep sulcus sign and very sharp border .Air rises the highest part of the chest is abuts over the lower mediastinum

1.Air from bullae/pneumothorax2.Ruptured airway3.Ruptured oesophagus-commonest cause iatrogenic from endoscopy4.Air from retroperitoneum

1.Cavitating disease in right upper lobe and apical segment of left lower lobe. This is reactivation/secondary TB.Other cavitating organisms..

2.Septic emboli-strep(pneumatocoelees) and staph (true cavitation). Straight forward staph and strep also can.3.Aspiration –gram negatives4.Haemophillus

Apico-posterior (LUL)

Apical (LLL)

Posterior (LLL)

Posterior (RUL)

Apical (RLL)

Posterior (RLL)

Dependant segments in the supine position

Large cavitating mass1.TB2.Cavitating tumour3.Abscess-in dependent areas4.Aspergilloma in old TB or ankylosing spondylitis scarring (upper lobes)5.Hydatid rare