Index
It refers to the anatomical position of the human being.
The dorsal decubitus (right or left) position is an excellent alternative to obtain a lateral decubitus or an image of erect abdominal X-rays when a patient can not stand up or lie on their side.
It can provide information on pneumoperitoneum and air-fluid levels in cases of suspected acute abdominal trauma. The examination can be performed at the patient’s location with a mobile X-ray unit, such as the ICU.
This view can also help evaluate an incisional hernia or the diameter of a calcified aortic aneurysm.
Patient’s position:
Place the patient in a supine position on a radiolucent pad with the right or left side against the device of the grid. Raise your arms and place them next to your head or your upper chest. Establishing support under the knee helps relieve tension when the patient is supine.
Position of the abdomen:
The most commonly used abdominal reference point is the iliac crest, which corresponds to the level of the middle abdomen and is at the vertebral level between spaces L4-L5. The iliac crest is in the highest position of the curved edge of the ilium.
Position the patient to a point approximately 2 inches (5 cm) above the level of the iliac crests and that center. Make sure that rotation does not occur from the prone position.
The maximum relaxation of the abdominal muscles is essential. The ease of the abdominal muscles is facilitated by supporting and slightly flexing the patient’s knees.
The exposure is done at the end of the expiration and should begin 1-2 seconds after stopping breathing. Ask the patient to breathe deeply, let out their breath and hold the position while not inhaling.
This moves the diaphragm to a higher position, which results in better visualization of the abdominal viscera.
Central ray:
The central ray should be horizontal and perpendicular to the center and should be directed to the mid-coronal plane, 2 inches (5 cm) above the level of the iliac crests.
Collimation:
The collimation is adjusted to center the mid-coronal plane of the patient in the IR margins, making sure that the upper and lower soft tissues surrounding the abdomen are included.
Close collimation is essential due to the more excellent dispersion of a high kVp and the need for soft tissue visibility.
Lateral decubitus position and lateral cross-table images: if the patient can not be stopped, a picture of the patient should be obtained in a lateral decubitus position with a horizontal beam.
This method results in less penetration of the abdominal viscera but a good visualization of small amounts of additional food gas. Alternatively, this information can be obtained in an image of the abdomen taken with the patient in the dorsal decubitus position.
This position is usually adequate to provide the required image and should be used in patients with a vertical position image that is not practical.
Chest images:
In a patient with abdominal pain, a chest image with the patient in an upright position is helpful for two reasons: it facilitates the detection of small amounts of free intraperitoneal air. It may demonstrate an unsuspected chest disease that is causing abdominal pain.
Panoramic views are more sensitive to detecting pneumoperitoneum than abdominal images taken with the patient in an upright position.
This difference in sensitivity occurs because the X-ray beam is centered on the iliac crest of the abdominal images so that it penetrates the air under the diaphragm obliquely rather than tangentially.
In addition, the exposure technique required to penetrate the abdomen obscures small collections of free intraperitoneal air.
Series of perforations:
This term is sometimes used to indicate abdomen views, including vertical images in an upright position, supine decubitus, lateral decubitus, and PA in the thorax. This series aims to increase the sensitivity for the detection of free intraperitoneal air in case of visceral perforation.
