CHEST X-RAYS QUALITY,,,,,,,,,,,,,,,, pptx

CHEST XRAYS QUALITY

1. CHEST XRAY BASICS 1.QUALITY

2. XRAY DENSITIES Air – Black Fat – Dark gray Soft tissue –Light gray Bone – White Metal – Very white

3. Chest X-ray Quality It is important to assess the quality of the image b efore interpreting a chest X-ray Without this step you may diagnose disease that is not genuine or you may be wrongly reassured Quality is influenced by radiographic technique and patient factors Check the image for Anatomical inclusion Projection Rotation Inspiration and lung volume Penetration Artifact

4. ANATOMICAL INCLUSION Are all the necessary anatomical structures included? Image quality - anatomy inclusion First ribs? Lateral edges of ribs ? Costophrenic angles?

5. ANATOMICAL INCLUSION

6. PROJECTION Posterior-Anterior (PA) projection S tandard projection Not always possible Higher quality and more accurately assess heart size than AP images Anterior-Posterior (AP) projection If the patient is too unwell to stand Lower quality than PA images

7. AP projection : Heart size is exaggerated because the heart is relatively farther from the detector, and also because the X-ray beam is more divergent as the source is nearer the patient PA projection : The apparent heart size is nearer to the real size, as the heart is relatively nearer the detector Magnification of the heart is also minimised by use of a narrower beam, produced by the increased distance between the source and the patient

8. AP VS PA Due to AP magnification: Superior mediastinum appears widened H eart appears enlarged D iaphragm is higher – underinflation S capulas overlap the lungs In the lower lung zones there appears to be a bilateral interstitial infiltrate – also due to underinflation

9. PA VS AP In PA view Clavicles don’t project too high into the apices or thrown above the apices (more horizontal) Heart wont be magnified Scapula are away from the lung fields Ribs are obliquely oriented in PA view Spine and posterior ends of ribs are clearly seen

10. ROTATION The spinous processes of the thoracic vertebrae are in the midline at the back of the chest They should form a vertical line that lies equidistant from the medial ends of the clavicles, which are at the front of the chest Rotation of the patient will lead to off-setting of the spinous processes so they lie nearer one clavicle than the other Rotation may lead to misinterpretation of heart contours, tracheal position and lung appearances

11. NO ROTATION The spinous processes should lie half way between the medial ends of the clavicles

12. ROTATION AND HEART SIZE

13. Rotation and the lungs Thickness of soft tissues of the chest, such as breast tissue, is altered by rotation This may give the misleading impression of pathology in the lungs

14. ROTATED FILM

15. ROTATED FILM Pseudo-blunting of the costophrenic angle At first glance the left costophrenic angle appears blunt The patient is rotated which results in greater thickness of breast tissue overlying the costophrenic angle on the left compared with the right You may be misled into thinking there is a pleural effusion or other pathology causing costophrenic angle blunting

16. INSPIRATION AND LUNG VOLUME Chest X-rays are conventionally acquired in the inspiratory phase of the respiratory cycle The radiographer asks the patient to, breathe in and hold his breath If the image is acquired in the expiratory phase Lungs  Relatively airless Lung density  I ncreased P osition of the diaphragm  Raised E xaggeration of heart size Obscuration of the lung bases

17. Assessing inspiration Count ribs down to the diaphragm The diaphragm should be intersected by the 5th to 7th anterior ribs in the mid- clavicular line Less is a sign of incomplete inspiration Assessing for hyperexpansion >7th anterior rib intersecting the diaphragm at the mid- clavicular line Sign of obstructive airways disease F lattening of the hemidiaphragms

18. INSPIRATORY FILM Anteriorly the fifth rib intersects the diaphragm at the mid- clavicular line The lungs are not consolidated The heart size is clearly normal

19. EXPIRATORY FILM Anteriorly only the third rib intersects the diaphragm at the mid- clavicular line The lung bases are white Heart size is increased

20. NORMAL EXPANSION This patient has taken a good breath in such that the diaphragm is intersected by the 6th rib in the mid- clavicular line The hover over image shows an imaginary  dotted line  between the costophrenic and cardiophrenic angles The distance between this line and the diaphragm ( green lines ) should be greater than 1.5 cm ( asterisk ) in normal individuals

21. HYPEREXPANSION >7th anterior rib intersecting the diaphragm at the mid- clavicular line F lattening of the hemidiaphragms

22. PENETRATION Penetration is the degree to which X-rays have passed through the body A well penetrated chest X-ray is one where the vertebrae are just visible behind the heart The left hemidiaphragm should be visible to the edge of the spine Digital correction may compensate for an incorrectly penetrated X-ray Loss of the hemidiaphragm contour or of the paravertebral tissue lines may be due to lung or mediastinal pathology

23. Under penetration The left hemidiaphragm is not visible to the spine Lung tissue behind the heart cannot be assessed Re-windowing (hover over image) The diaphragm ( long arrows ) is visible to the spine The left paravertebral soft tissues are visible ( short arrows ) ,right side of the spine is clear ( arrowheads ) There is no abnormality of lung tissue behind the heart

24. GOOD QUALITY CHEST XRAY

25. ARTIFACT Artifactual appearances seen on a chest X-ray may be due to radiographic technique, patient factors, or the presence of external or internal non-anatomical objects Radiographic artifact This is spurious or unclear appearance of an anatomical structure due to radiographic technique Example s : Rotation , incomplete inspiration and incorrect penetration C lothing or jewellery not removed Patient artifact Examples: Poor co-operation with positioning or movement Very often obesity exaggerates lung density Occasionally normal anatomical structures such as hair or skin folds can cause confusion

26. ARTIFACTS IN CHEST XRAY

27. ARTIFACTS IN CHEST XRAY

28. HAIR ARTIFACT At first glance the soft tissues at the base of the neck on the right look abnormal Appearances simulate surgical emphysema This artifact is due to hair which was draped around the patient's neck

29. Medical/surgical artifact Some chest X-rays are performed solely to assess the position of medical devices External medical devices not part of the X-ray assessment should be removed by radiographers prior to image acquisition, unless it is dangerous to do so

30. Naso -gastric (NG) tube placement Clinicians are often required to check the position of a naso -gastric tube The tube tip should be below the level of the diaphragm ( dotted line ), and ideally should be at least 10cm beyond the gastro- oesophageal junction ( asterisk ) This tube is only just in the stomach and so was advanced and the position rechecked prior to using it for feeding The tip of a naso -gastric tube should also lie on the left If it crosses the midline it has entered the duodenum