Chest x ray - basics

Doctor at Olive Hospitals en Olive Hospitals
15 de Feb de 2017

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Chest x ray - basics

  1. Dr Rikin Hasnani
  2. • Introduction • Procedure of taking an x ray • Projections and views of chest X ray • Reading a Chest X ray
  3. • German physicist Wilhelm Röntgen was the first person to discoverer X-rays in 1895, and he was the first to systematically study them. • He is the one who gave them the name "X-rays", though many referred to these as "Röntgen rays"
  4. • X-rays are a form of ionizing electromagnetic radiation. • Most X-rays have a wavelength in the range of 0.01 to 10 nanometers • The voltage used for diagnostic X rays is in range of 20 – 150kV
  5. A radiograph is an X-ray image obtained by placing a part of the patient in front of an X-ray detector and then illuminating it with a short X-ray pulse X ray detectors used to collect images are • photographic film • scintillator • semiconductor diode • photostimulable phosphor plates, or PSP
  6. Before the procedure •The doctor/technician should explain the procedure to pt and offer him/her opportunity to ask any questions that pt might have about the procedure. •Generally, no prior preparation, such as fasting or sedation, is required. •Notify the radiologic technician if pt is pregnant or suspect that pt may be pregnant.
  7. •Pt is asked to remove any clothing, jewelry, or other objects that may interfere with the particular view that is ordered. •Pt is positioned carefully so that the desired view of the chest is obtained. •For a standing or sitting film, pt stands or sits in front of the X-ray plate. Pt is asked to roll his shoulders forward, take in a deep breath, and hold it until the X- ray exposure is made. For patients who are unable to hold their breath, the radiologic technician takes the picture at the appropriate time by watching the breathing pattern.
  8. • There are 5 basic radiographic densities • Gas, fat, soft tissue (water), bone and metal • Anatomic structures are recognized on x-ray by their density differences • Two substances of the same density in direct contact can’t be differentiated • Loss of the normal radiologic silhouette (contour) is called the “silhouette sign”
  9. On the left is a simulated patient in position for a standard PA (posterior anterior) chest x-ray. On the right is a normal PA film.
  10. Supine AP (anteriorposterior) position, the x-ray tube is 40 inches from the patient
  11. 1) In AP view, the posterior chest is well demonstrated. 2) The scapulae overlies the upper lung areas and 3) the clavicles are projected more cranially over the apices. 4) The disc spaces of lower cervical spines are more clearly seen. 5) The heart is magnified. 6) The ribs may appear more horizontal 7) Lung fields are shortened
  12. • To localise a lesion seen on PA view • To clarify lobar collapse or consolidation • To explore a retrosternal or retrocardiac shadow • To confirm the presence of encysted fluid in oblique fissure (pseudotumor)
  13. •This could be helpful to assess the volume of pleural effusion and demonstrate whether a pleural effusion is mobile or loculated. •You could also look at the nondependent hemithorax to confirm a pneumothorax in a patient who could not be examined erect. •Additionally, the dependent lung should increase in density due to atelectasis from the weight of the mediastinum putting pressure on it. •Failure to do so indicates air trapping
  14. It is used to visualize the apex of the lung, to pick-up abnormalities such as a Pancoast tumour.
  15. Reading a Chest X ray
  16. •Confirm Demographic data first
  17. 1. Penetration 2. Inspiration 3. Angulation 4. Rotation
  18. On a properly exposed chest radiograph: • The lower thoracic vertebrae should be visible through the heart • The bronchovascular structures behind the heart (trachea, aortic arch, pulmonary arteries, etc.) should be seen
  19. an example of a normal PA film that is underpenetrated In an underexposed chest radiograph, the cardiac shadow is opaque, with little or no visibility of the thoracic vertebrae. The lungs may appear much denser and whiter, much as they might appear with infiltrates present.
  20. With greater exposure of the chest radiograph, the heart becomes more radiolucent and the lungs become proportionately darker. In an overexposed chest radiograph, the air-filled lung periphery becomes extremely radiolucent, and often gives the appearance of lacking lung tissue, as would be seen in a condition such as emphysema
  21. The chest radiograph should be obtained with the patient in full inspiration to help assess intrapulmonary abnormalities. At full inspiration, the diaphragm should be observed at about the level of the 8th to 10th rib posteriorly, or the 5th to 6th rib anteriorly. Poor inspiration results in high diaphragms and crowding of normal lung markings.
  22. •A patient can appear to have a very abnormal chest if the film is taken during expiration. - On the first film, the loss of the right heart border silhouette would lead you to the diagnosis of a possible pneumonia. However, the patient had taken a poor inspiration. - On repeat exam with improved inspiration, the right heart border is normal.
  23. • Airway • Bones e.g. rib fractures and lytic bone lesions • Cardiac silhoutte, (mediastenum) • Cardiophrenic and Costophrenic angles • Diaphragm, • External lung fields • Fields (lung parenchyma), • Gas • Hilum
  24. • Start your assessment of every chest x-ray by looking at the airways. • The trachea should be central or slightly to the right. • If the trachea is deviated, it is important to establish if this is because the patient has been incorrectly positioned (rotated), or if there is pathology. • If the trachea is genuinely deviated you should then try to decide if it has been pushed or pulled by a disease process
  25. • You should be able to count and number the ribs, inspect the scapulae, humerus and shoulders, clavicles, and see the diaphragms overlying the posterior aspects of the 10th or 11th ribs . • The spine and sternum are generally difficult to visualize in detail on standard PA films due to overlying shadows.
  26. • It is ovoid shadow with apex pointing towards left occupying less than half of the transthorasic diameter.
  27. On a frontal chest x-ray the costophrenic angles should form acute angles which are sharp to a point. --Often the term costophrenic "blunting" is used to refer to the presence of a pleural effusion. This, however, is not always correct and costophrenic angle blunting can be related to other pleural disease, or to underlying lung disease.
  28. Divide lung fields into zones: upper, middle, and lower zones -Upper: from the apex to 2nd costal cartilage -Middle: between 2nd and 4th costal cartilage -Lower: between 4th and 6th costal cartilage
  29. Oblique fissure more clearly seen on lateral view , extends from T4-T5 vertebrae to reach the diaphragm and 5cm behind the costophrenic angle on left and just behind the angle on right Horizontal fissure more clearly seen on PA view extending from right hilum to 6th rib in the axillar line. Right oblique fissure Left oblique fisure Horizontal fissure
  30. • Right upper lobe:
  31. • Right middle lobe:
  32. • Right lower lobe:
  33. • Left lower lobe:
  34. • Left upper lobe with Lingula:
  35. • --Look at the hilum (which consists of main bronchus and pulmonary arteries) • --The left hilum should be higher than the right. • --Compare shapes and densities on both sides. • --The hila (lung roots) are mainly consisting of the major bronchi and the pulmonary veins and arteries. These structures pass through the narrow hila on each side and then branch as they widen out into the lungs. • --The hila are not symmetrical but contain the same basic structures on each side.