(Basic facts about projection in X ray films)
📐Postero-anterior (PA) will not produce as much magnification of the heart and mediastinum as an antero-posterior (AP) projection. So PA films are the preferred ones.
📐A PA film is taken with the film cassette in front of the patient and the beam delivered from behind with the patient in an upright position.
📐Portable films and those taken in ICUs are all AP projection.
📐The supine position causes distension of the upper lobe blood vessels, which may be confused with elevated left atrial pressure
📐A lateral X-ray is useful in localising lesions in the AP dimension, locate lesions behind the left side of the heart or in the posterior recesses of the lungs.
📐A left lateral (with the left side of the chest against the film and the beam projected from the right) is the standard projection.
📐The heart is magnified less with a left lateral as it is closer to the film.
📐To visualize lesions in the left hemithorax, obtain a left lateral film and for right-sided lesions a right lateral.
📐Expiratory films are used to assess air trapping in bronchial obstruction such as a foreign body.
📐A pneumothorax always appears larger on an expiratory film and occasionally a small pneumothorax may only be visible on expiration.
📐Films if accidentally taken in expiration, can result in spurious magnifcation of the heart and mediastinum.
#xray ,#radiology ,#imaging , #XrayBasics , #anaesthesia
Reference: Radiology for Anaesthesia and Intensive Care (Richard Hopkins, Carol Peden and Sanjay Gandhi)
No comments:
Post a Comment