Basic Chest Radiology 2

Basic Chest Radiology 2 Airspace shadowing Nodes , nodules and masses Air where it should not be!

The smallest unit we can see on CT scans 3 cm long Best anatomical organisation in the lower lobe The secondary pulmonary lobule Centrilobular Pulmonary arteries Pulmonary veins and lymphatics

Septal lines and a lamellar effusion

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 Radiological signs of pulmonary oedema

Classic radiological consolidation

Diagnosis depends on history 1.Oedema-cardiac or non cardiac 2.Pneumonia 3.Aspiration 4.Haemorrhage 5.Alveolitis for any cause

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 Lymph nodes

1.Sarcoid-bilateral symmetrical 2.TB-usuallY unilateral 3.Lymphoma-usually bilateral asymmetrical 4.Ca-usually unilateral 5.Metastatic-unilateral or asymmetrical 6.Fungal-unusual in UK

If in doubt use the surgical sieve SPN 1.Primary tumour-malignant or benign 2.Harmatoma 3.granuloma-TB 4.Solitary metastases 5.Solitary AVM 6.Round pneumonia 7.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 disease 3.AVMs-may see feeding vessels 4.Wegeners-isually cavitating 5.Septic emboli-usually staph or strep 6.Multiple granuloma-usually small with calcification.

Micronodular disease • 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

1.Miliary TB 2.Atypical pneumonia 3.Miliary metastases and Lymphoma 4.3.Sarcoidosis 5.Extrinsic allergic alveolitis(soft)

Pneumothorax • Look for a pleural line • 2cm edge corresponds to 50% of volume • Should always aim for an erect film • There is no evidence that an expiratory film is more sensitive • Decubitus or lateral may be helpful • Beware a tension pneumothorax, mediastinal shift away and flattening of hemidiaphragm, increased pressure causes decreased venous return and death/compromise. • 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/pneumothorax 2.Ruptured airway 3.Ruptured oesophagus-commonest cause iatrogenic from endoscopy 4.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 negatives 4.Haemophillus

Large cavitating mass 1.TB 2.Cavitating tumour 3.Abscess-in dependent areas 4.Aspergilloma in old TB or ankylosing spondylitis scarring (upper lobes) 5.Hydatid rare

Basic Chest Radiology 2