Show
Citation, DOI & article dataCitation: Murphy, A. Chest (PA view). Reference article, Radiopaedia.org. (accessed on 16 Oct 2022) https://doi.org/10.53347/rID-44853 The posteroanterior (PA) chest view examines the lungs, bony thoracic cavity, mediastinum and great vessels. On this page:The chest x-ray is the most common radiological investigation in the emergency department 1. The PA view is frequently used to aid in diagnosing a range of acute and chronic conditions involving all organs of the thoracic cavity. Additionally, it serves as the most sensitive plain radiograph for the detection of free intraperitoneal gas or pneumoperitoneum in patients with acute abdominal pain.
The entire lung fields should be visible from the apices down to the lateral costophrenic angles.
The phase of respiration has a profound effect on the appearance of several structures on the chest radiograph (see Case 2 for inspiration and expiration images in the same patient). A poor-inspiratory PA radiograph can mimic pathology. Structures that can appear different on expiration include:
Rotation of a chest radiograph can simulate common pathological processes and make it hard to produce an appropriate diagnosis. The PA view is used to investigate a plethora of conditions and it is the radiographer's responsibility to ensure high-quality diagnostic images are achieved consistently. The sternoclavicular joints are a sound indicator for positional rotation, if one sternoclavicular joint is notably wider than the other, that respected side needs to be rotated toward the image receptor to correct rotation. Patients with a longstanding history of emphysema or COPD will have abnormally long lungs compared to the general population, remember this when collimating superior to inferior. Side marker placement is imperative; patients can have congenital conditions that mimic a mirrored image 2. Remember to explain to your patient what you are about to do; that is ask them to take a breath in and hold it. Many times this gives the patient time to prepare and results in a better breath hold and therefore a higher quality radiograph. Always remember to tell your patient to breathe again! Quiz questionsReferencesRelated articles: Imaging in practicePromoted articles (advertising)What is the purpose of the 72 inch SD used for chest radiography?Several authors have suggested that chest radiog- raphy should be performed with a 72-inch source-to- image-receptor distance (SID) to reduce magnification of the heart.
What is the rationale for using a 72 inch source to image distance when performing chest radiographs?Whenever possible, a 72 inches (183 cm) source-to-image (SID) is used, to minimize magnification of the heart and to obtain a greater recorded detail of delicate lung structures. In conventional radiography of the chest a 120 inches (305 cm) SID is commonly used.
What is the recommended SID for routine radiography of the chest?In cooperative adults and older pediatric patients, fully upright portable chest radiographs should be performed at a source-image distance (SID) of 40 to 72 inches, with the optimal distance as close as possible to 72 inches.
How far above the shoulders should the IR be positioned for PA and lateral chest radiograph?Place the film cassette holder (or IR) crosswise or lengthwise depending on the patient's physique, using a 14 x 17-inch (35 x 43-cm) IR. Place the IR against the left side of the patient. Adjust the height of the cassette so the upper border is 1 1/2 to 2-inches above the shoulder.
|