CHEST X-RAY MEDIASTINUM AND HILUMpptx.pptx

MEDIASTINUM AND HILUM IN CHEST XRAY

1. CHEST X-RAY MEDIASTINUM AND HILUM

2. Normal mediastinal contours If one of these contours is obscured, then an abnormality is likely to be located next to the structure that the contour represents

3. Anterior mediastinal mass - Thymoma The mediastinal contours are bulging due to a large mass – in this case a thymoma It is possible to determine that this mass is located anteriorly in the mediastinum The aortic knuckle (mid mediastinum) and both the azygo-oesophageal and descending aorta lines (posterior mediastinum) are clearly visible and so the mass cannot be located adjacent to these structures

4. Anterior mediastinal mass - Thyroid A large soft tissue mass causes narrowing of the trachea and deviates it towards the left side The right paratracheal stripe is obscured at the level of the mass but remains visible below the mass This patient had an enlarged thyroid gland ( goitre ) which was visible clinically and was shown to be benign on imaging with ultrasound

5. Superior mediastinal mass - Lymphoma A soft tissue mass widens the superior mediastinum The mass blends in with the upper edge of the aortic knuckle and obscures the right paratracheal stripe This mass was found to be lymphoma following lymph node biopsy Bilateral effusions are also present

6. Posterior mediastinal mas s A large round area of increased density indicates the presence of a soft tissue mass in the region of the left hilum L eft heart border (adjacent to the anterior mediastinum) remains well defined Vessels of the left hilum area – including the left pulmonary artery (middle mediastinum) – also remain well defined Obscuration of the descending aorta (posterior mediastinum) confirms the mass is located posteriorly

7. Unilateral hilar enlargement - Lung cancer In this image the left hilum is too big and too dense (white) and the normal pulmonary vessels are difficult to delineate Following bronchoscopy and tissue biopsy this mass was found to be a primary bronchogenic cancer

8. Bilateral hilar enlargement - Sarcoidosis In this image both the hila are enlarged and of increased density Bilateral hilar enlargement is the classic chest X-ray appearance of sarcoidosis – as was found to be the case in this patient following lymph node biopsy

9. Bilateral hilar enlargement - Lymphoma Bilateral hilar enlargement is not always sarcoidosis Lymph node biopsy showed this to be lymphoma rather than sarcoidosis

10. Radiation fibrosis This patient had been treated with radiotherapy for Hodgkin’s disease several years previously The lungs adjacent to the hila are scarred and appear of increased density (highlighted areas) Radiation fibrosis should not be diagnosed without a history of previous radiotherapy Distribution of lung scarring depends on the specific site irradiated

11. Aneurysmal descending aorta This image shows a grossly enlarged descending aorta due to a thoracic aortic aneurysm

12. Aneurysmal ascending aorta This patient had aortic stenosis due to a congenital bicuspid aortic valve The ascending aorta is enlarged due to post- stenotic dilatation – a common phenomenon in patients with aortic stenosis Patients with aortic stenosis may have a normal chest X-ray Patients may also have cardiomegaly indicating left ventricular failure – not yet developed in this patient

13. Aortic unfolding Unfolding’ of the aorta – a common X-ray finding in elderly patients – is a phenomenon which arises due to elongation of the ascending aorta with age It is not usually considered a pathological finding in itself and should not be mistaken for an aortic aneurysm It is often associated with calcification of the aorta – as in this image – which is a sign of atherosclerosis

14. Coarctation of the aorta Features of coarctation of the aorta may be visible on a chest X-ray Coarctation causes blood flow to be deviated from the upper part of the descending aorta into the intercostal vessels of the 4-8th ribs bilaterally which results in ‘notching’ of their inferior edge

15. Coarctation - figure 3 sign The narrowing ( coarctation ) results in the descending aorta taking on a contour said to resemble a figure ‘3’

16. Coarctation - Stent (Same patient as two images above) This patient has been treated with stent insertion at the point of coarctation

17. Hiatus hernia – Large Herniation of the stomach above the diaphragm (hiatus hernia) is a common finding on a chest X-ray Hiatus hernias may be very large – as in this image Seeing a gas/fluid level helps to make the diagnosis

18. Hiatus hernia – Small Here is a smaller hernia The gas/fluid level is less distinct Note: Hiatus hernia may not be visible on a chest X-ray

19. Pneumomediastinum M ay result from injury to the lungs or structures of the mediastinum such as the airways or oesophagus The mediastinal pleura is separated from the mediastinum and becomes visible as a thin white line This can be a very subtle finding and may be associated with other features of tracking gas such as surgical emphysema or pneumothorax