Lesson 1, Topic 1
In Progress

Bony Thorax, Chest, and Abdomen

April 11, 2024

Bony Thorax, Chest, and Abdomen

Learning Objective: Examine the process for performing bony thorax, chest, and abdomen images.

Radiographic imaging of the chest is the most common radiographic procedure (Procedure 38.1). Imaging of the chest and abdomen are performed to visualize structures and organs of the chest and abdomen.
The radiographic examinations of the thorax and abdomen typically require a 35 × 43 cm IR. Although the thorax and abdomen may have a similar thickness, imaging requires the application of different technical factors: high kVp for the large variations in the chest, moderate kVp to demonstrate the minor differences in tissue densities in the abdomen, and low kVp for the thin bones of the thoracic cage.
For the projections of the bony thorax, chest, and abdomen, use the following unless otherwise indicated:

• IR: Positioned by department protocol for proper anatomy orientation; CR plate 35 × 43 cm; portrait orientation.
• Grid and SID: Grid is used. SID 40 inches minimum.
• Collimation: Adjust the light field to 2.5 cm on all sides of the anatomy. Place anatomical marker in the light field on the lateral side of the anatomy.
• Patient instructions: Stop breathing on second deep inspiration.

Body Habitus

Accurate imaging of the chest and abdomen requires an awareness of body habitus—the general shape of the patient’s body. Organs vary significantly in size, shape, and location according to body types. The four basic types of body habitus are as follows(FIGURE 38.28):

• Sthenic: Considered the be average; about 50% of the population has this body type.
• Hyposthenic: Thought of as slender; about 35% of the population has this type.
• Asthenic: Considered very slender; about 10% of the population has this body type.
• Hypersthenic: Considered massive and stocky; about 5% of the population has this body type.

FIGURE 38.28  Four types of body habitus. From Long BW, Rollins JH, Smith BJ: Merrill’s atlas of radiographic positioning and procedures, ed 14, St. Louis, 2020, Mosby.

Positioning and Radiographic Examinations of the Chest

Learning Objective: Explain the positioning and radiographic examinations for the chest.

Chest radiography is done at 72 inches SID to minimize magnification of the heart. Exposures of the chest are made on inspiration to expand the lung fields. It is good practice to have patients take two deep inspirations, holding their breath in on the second inspiration. The greater the inspiration, the greater the depression of the diaphragm. Evidence of full inspiration is seen on a chest image when 10 ribs can be counted superior to the diaphragm. In preparation for chest examinations, the patient is instructed to remove all clothing and jewelry from the waist up and to don a gown that opens in the back.

Routine Examination of the Chest

The routine examination of the chest includes the PA and left lateral projections. When a patient is unable to stand for the PA projection, the AP projection can be substituted.

• SID: 72 inches if possible.
• Body and part position: Standing, facing IR holder.

• PA: Anterior surface of the chest is against upright Bucky with coronal plane parallel to IR. The backs of hands are placed on hips, and shoulders are rotated anteriorly. This arm position rotates the scapulae out of the lung fields. IR is aligned 1.5 to 2 inches above the spinous process of C7 (FIGURE 38.29).
• AP: Patient supine or seated (typically in a wheelchair) with arms at side. IR is aligned so that upper margins are 1.5 to 2 inches above level of shoulders.
• Lateral: Both arms are raised overhead, with the patient grasping opposite elbows. Left side of body is in contact with IR, and midcoronal plane is perpendicular to center of IR. IR is unchanged from PA projection (FIGURE 38.30).

• CR:

PA: Perpendicular to center of IR, entering at midline approximately at level of T7, which corresponds to the level of the inferior angle of the scapulae.
AP: Perpendicular to center of IR. Center point should be on the midsagittal plane at a level 3 inches below the jugular notch.
Lateral: Perpendicular to center of IR. Center point should be on the midcoronal plane at the level of T7.

Supplemental Projections of the Chest

If the patient cannot perform the typical projections for the chest, supplemental projections may be performed due to trauma or pathology. Supplemental projections utilize modified positioning to obtain the needed projections.

AP or PA Projection (Lateral Decubitus Position)

• SID and patient instructions: Same as the routine examination of the chest.
• Body and part position: Recumbent, lying on side of interest. Midsagittal plane of chest horizontal. Chest elevated 2 to 3 inches on a radiolucent pad. Anterior or posterior surface of chest against a vertical grid device.
• CR: Horizontal and perpendicular to center of IR. Center point should midsagittal and at the level of T7.
• Structures seen: Heart, lungs, and mediastinum. Sternoclavicular joints equidistant from spine, which indicates no rotation. Any free fluid will be demonstrated along the independent chest wall.

Chest (Lung Apices)

The lungs’ apical zone (apices) is one of the four chest radiographic zones and an important location for missed diagnoses when reporting a PA chest. The other three areas are behind the heart, below the diaphragm, and the bones and soft tissues.

AP Axial Projection (Lordotic Position)

• SID and patient instructions: Same as the routine examination of the chest.
• Body and part position: Standing. Patient stands facing the x-ray tube, 8 to 12 inches in front of upright Bucky; patient then arches back and places shoulders against Bucky. Sagittal plane is perpendicular to IR. Backs of hands are placed on hips, and shoulders are rotated anteriorly, which rotates the scapulae out of the lung fields. IR is aligned so that upper margin is 3 inches above border of shoulder.
• CR: Perpendicular to center of IR. Center point should be midsagittal and at the level of the sternum.
• Structures seen: Apices of both lungs, free of superimposition by the clavicles.

Positioning and Radiographic Examination of the Ribs

Learning Objective: Explain the positioning and radiographic examinations for the ribs.

Rib studies may be done with the patient recumbent or upright. Upright positions are usually most comfortable for patients with rib injuries. Ribs are named both by anatomic location and in relation to the diaphragm. The upper ribs are cephalad to the diaphragm, and the lower ribs are below the diaphragm. The anterior aspects of the ribs are anterior ribs, and the posterior aspects are posterior ribs. The lateral aspects are axillary ribs because they are located within or near the axillary region.

FIGURE 38.29  Chest. (A) Position for PA projection. (B) PA projection. A, from Long BW, Rollins JH, Smith BJ: Merrill’s atlas of radiographic positioning and procedures, ed 14, St. Louis, 2020, Mosby. B, from Long BW, Frank ED, Ehrlich RA: Radiography essentials for limited practice, ed 6, St. Louis, 2021, Elsevier.

A rib examination usually consists of AP or PA and oblique projections. The ribs nearest the IR are the area of interest. It is customary to perform AP projections when the area of clinical interest is primarily posterior and to perform PA projections for greater detail of the anterior ribs. AP or PA projections demonstrate the anterior and posterior portions of the ribs in the coronal plane. Oblique projections are used to demonstrate the axillary portions of the ribs. Lateral projections are not useful because they result in the superimposition of the right and left ribs. For posterior ribs, RPO is used for right ribs, and the left posterior oblique (LPO) is used for left ribs. The RAO is used for the left ribs, and the LAO is used for the right ribs.

Upper Posterior Ribs: AP and AP Oblique Projections

• Body and part position: Standing or recumbent.

• AP: Supine on table or upright with posterior surface of chest against upright Bucky. Coronal plane is parallel to IR. Upper margin of IR is 1.5 to 2 inches above level of spinous process of C7.

FIGURE 38.30  Chest. Position for lateral projection. From Long BW, Rollins JH, Smith BJ: Merrill’s atlas of radiographic positioning and procedures, ed 14, St. Louis, 2020, Mosby.

FIGURE 38.31  Ribs. Position for AP oblique projection. From Long BW, Rollins JH, Smith BJ: Merrill’s atlas of radiographic positioning and procedures, ed 14, St. Louis, 2020, Mosby.

  • AP oblique: RPO position for right ribs or LPO position for left ribs. Coronal plane forms a 45-degree angle with IR plane. Upper margin of IR is 1.5 to 2 inches above level of spinous process of C7 (FIGURE 38.31).

• CR:

AP: Perpendicular to center of IR. Center point should be on the midsagittal plane at a level 3 inches below the jugular notch.
Lateral: Perpendicular to center of IR. Center point should be on the midcoronal plane at the level of T7.

• Patient instruction: Stop breathing.
• Structures seen: Ribs 1 to 10. Posterior portions are best seen on AP projection; axillary portions are best seen on oblique projection.

Upper Anterior Ribs: PA and PA Oblique Projections

• Body and part position: Standing or recumbent.

• PA: Supine on table or upright with anterior surface of chest against upright Bucky. Coronal plane is parallel to IR. Upper margin of IR is 1.5 to 2 inches above level of spinous process of C7.
• PA oblique: RAO position for right ribs or LAO position for right ribs. Coronal plane forms a 45-degree angle with IR plane. Upper margin of IR is 1.5 to 2 inches above level of spinous process of C7.

• CR:

• PA: Perpendicular to center of IR. Center point should be in midclavicular line at approximate level of axillary fold.
• PA oblique: Perpendicular to center of IR. CR enters at a point midline of posterior surface midway between spine and midaxillary line of affected side at approximate level of axillary fold.

• Patient instruction: Stop breathing on inspiration.
• Structures seen: Ribs 1 to 10. Anterior portions are best seen on PA projection; axillary portions are best seen on oblique projection.

AP or PA Projection (Lateral Decubitus PositionLower Posterior Ribs: AP and AP Oblique Projections )

• Body and part position: Standing or recumbent.

• AP: Supine on table or upright with posterior surface of chest against upright Bucky. Coronal plane is parallel to IR. Lower margin of IR is at level of iliac crest.
• AP oblique: RPO position for right ribs or LPO position for left ribs. Coronal plane forms a 45-degree angle with IR plane. Lower margin of IR is at level of iliac crest.

• CR:

       AP: Perpendicular to center of IR. Center point should be in midclavicular line at approximate level of tip of xiphoid process.

• AP oblique: Perpendicular to center of IR. CR enters at a point midline of anterior surface at approximate level of tip of xiphoid process.

• Patient instruction: Stop breathing on expiration.
• Structures seen: Ribs 8 to 12. Posterior portions are best seen on AP projection; axillary portions are best seen on oblique projection.

Positioning and Radiographic Examinations of the Abdomen

Learning Objective: Explain the positioning and radiographic examinations for the abdomen.

Radiographic examinations of the abdomen may consist of one or more projections, depending on the purpose of the examination. The primary projection is the AP projection in the supine position, also called a “kidneys, ureters, and bladder” (or KUB) projection. Also, decubitus projections may be performed to evaluate the abdominal aorta.

Routine Examination of the Abdomen

The routine examination of the abdomen includes the AP projection in the supine position. Supplemental images are produced in the upright and left lateral decubitus positions.

• Body and part position: The patient is supine. Sagittal plane is perpendicular to IR, and the knees may be flexed moderately and supported by a bolster. The IR is centered at the level of iliac crests. The inferior margin of IR should be at the level of the greater trochanter to ensure inclusion of pelvic floor (FIGURE 38.32).
• CR: Perpendicular to center of IR through a point in midline at level of iliac crest.

FIGURE 38.32  Abdomen. (A) Position for AP projection. (B) AP projection, patient recumbent. A, from Long BW, Rollins JH, Smith BJ: Merrill’s atlas of radiographic positioning and procedures, ed 14, St. Louis, 2020, Mosby. B, from Long BW, Frank ED, Ehrlich RA: Radiography essentials for limited practice, ed 6, St. Louis, 2021, Elsevier.

• Collimation: Adjust the light field to 2.5 cm on all sides of the anatomy. Place anatomical marker in the light field on the lateral side of the anatomy.
• Patient instruction: Stop breathing on expiration.
• Structures seen: Abdominal contents between diaphragm and pelvic floor. When exposure is correct, psoas muscles, liver margin, and kidney shadows should be visible.

Supplemental Projections

If the patient cannot perform the routine projections for the abdomen, supplemental projections may be performed due to trauma or pathology. Supplemental projections utilize modified positioning to obtain the needed projections. For these projections, the patient must stop breathing on inspiration during the exposure.

AP Projection (Upright Position)

• Body and part position: Standing, facing the x-ray tube. Midsagittal plane is perpendicular and centered to IR.
• CR: Perpendicular to center of IR through a point in midline approximately 2 inches superior to level of iliac crest.
• Structures seen: Abdominal contents between diaphragm and pelvic floor included. Diaphragms must be seen at top of IR. Air-fluid levels will be visible in intestines, if present. Free intraperitoneal air, if present, may be seen beneath diaphragm.

AP Projection (Left Lateral Decubitus Position)

Radiographic examination of the abdomen is critical for evaluating pathology. Abdominal x-rays can be utilized to determine the cause of abdominal pain, such as kidney stones, intestinal blockage, masses, or blockages.

Pathology

Learning Objective: Describe the pathology found in the examination of the abdomen.

Radiographic examination of the abdomen is critical for evaluating pathology. Abdominal x-rays can be utilized to determine the cause of abdominal pain, such as kidney stones, intestinal blockage, masses, or blockages.

• Bony thorax: The most common reason for imaging the bony thorax is trauma. Nontraumatic pathology includes malignant bone disease, multiple myeloma, metastatic bone lesions, and osteochondroma.
• Air-fluid levels: When fluid is present in a space usually occupied by air, it is a meaningful diagnostic sign of pathology. The interface between air and fluid is clearly visible radiographically. The possibility of abnormal air-fluid levels exists in the chest, abdomen, and paranasal sinuses. A horizontal x-ray beam is necessary to demonstrate air-fluid levels.
• Chest: Many acute and chronic conditions may affect the organs of the chest and can be evaluated radiographically. Trauma of the chest may result in lung collapse or atelectasis. Other pathology includes pneumothorax, pneumonia, pneumoconiosis, lung cancer, emphysema, tuberculosis, congenital malformations, and pleural effusion.
• Abdomen: Many abdominal structures, mainly the internal contours of abdominal organs, cannot be seen radiographically without contrast media. Contrast media is a liquid suspension of barium sulfate, and it can be ingested or injected. Conditions that may be diagnosed by abdomen imaging include enlargement of the liver and kidneys, displacement of the kidneys, abnormal gas patterns in the bowel, free intraperitoneal air, and calcifications such as kidney stones, gallstones, and calcification in arteries.