ARRT - American Registry of Radiologic Technologists Thorax and Abdomen Procedures Questions and Answers — Questions and Answers
Question 1: A patient is sent to radiology for a chest examination to rule out a small pneumothorax. The patient is able to stand and cooperate. In addition to the standard PA projection on full inspiration, which of the following would be most beneficial to demonstrate this condition?
- AP Lordotic
- PA with full expiration (Correct answer)
- Lateral decubitus with affected side down
- RAO oblique
Correct answer: PA with full expiration
A pneumothorax is air in the pleural space. An exposure made on full expiration decreases the volume of the lungs, making the lung tissue appear more dense. This increased density provides greater contrast against the free air in the pleural space, making a small pneumothorax easier to visualize. [22, 23]
Question 2: A three-way acute abdomen series is ordered on an ambulatory patient. Which of the following combinations of projections is typically included in this series?
- AP supine, AP upright, and Lateral decubitus
- AP supine, PA chest, and Lateral abdomen
- AP supine, AP upright, and PA chest (Correct answer)
- Prone, Lateral, and AP upright
Correct answer: AP supine, AP upright, and PA chest
The standard three-way acute abdomen series consists of an AP supine view to assess bowel gas patterns, an AP upright view to demonstrate air-fluid levels, and a PA chest x-ray. The PA chest is the most sensitive view for detecting small amounts of free intraperitoneal air (pneumoperitoneum) under the diaphragm. [2, 6, 13]
Question 3: When performing a radiograph of the sternum in the right anterior oblique (RAO) position, which of the following techniques is employed to improve visualization of the sternum?
- Short SID and suspended deep inspiration.
- High kVp and suspended expiration.
- A long SID and a rapid, deep inspiration.
- A long exposure time with shallow breathing. (Correct answer)
Correct answer: A long exposure time with shallow breathing.
To visualize the sternum in the RAO position, it is projected over the heart's homogenous shadow. An orthostatic (or breathing) technique, which uses a long exposure time (e.g., 2-3 seconds) and low mA while the patient breathes shallowly, is used to blur the overlying lung markings and ribs. This blurring makes the sharp outlines of the sternum more visible. [5, 7, 10]
Question 4: During a double-contrast barium enema (BE), the radiologist wants to visualize the medial side of the ascending colon and the lateral side of the descending colon coated with barium and filled with air. Which position should the technologist use?
- Left lateral decubitus (Correct answer)
- Right lateral decubitus
- Ventral decubitus
- AP upright
Correct answer: Left lateral decubitus
In a double-contrast study, air rises to fill the uppermost portions of the colon. In the left lateral decubitus position, the patient's right side is up. Therefore, air will rise to fill the right-sided structures (ascending colon) and the lateral wall of the left-sided structures (descending colon), providing an optimal double-contrast view of these specific areas.
Question 5: A patient has sustained trauma to the left posterior ribs, specifically ribs 9 and 10. Which of the following positioning and breathing instructions are most appropriate for the oblique projection to best demonstrate this injury?
- Left posterior oblique (LPO), suspended inspiration
- Right posterior oblique (RPO), suspended expiration
- Left posterior oblique (LPO), suspended expiration (Correct answer)
- Left anterior oblique (LAO), suspended inspiration
Correct answer: Left posterior oblique (LPO), suspended expiration
To demonstrate posterior ribs, the affected side is placed closest to the image receptor; therefore, an LPO is used for the left posterior ribs. [30] Examinations of ribs below the diaphragm (ribs 9-12) should be performed on suspended expiration to elevate the diaphragm, which provides a less dense background and better visualization of the lower ribs. [7, 15, 24]
Question 6: Which of the following best describes the primary purpose of obtaining RPO and LPO projections during an intravenous urogram (IVU)?
- To visualize the renal arteries branching from the aorta.
- To place the kidney on the side moved *away* from the IR (the "up" side) parallel to the IR. (Correct answer)
- To demonstrate the mobility of the kidneys (nephroptosis).
- To force contrast into the minor calyces using compression.
Correct answer: To place the kidney on the side moved *away* from the IR (the "up" side) parallel to the IR.
The kidneys lie obliquely in the posterior abdomen. An oblique projection (typically 30 degrees RPO or LPO) rotates the body to place the kidney on the "up" side (the side moved away from the IR) parallel to the plane of the image receptor. For example, in an RPO position, the left kidney is best demonstrated. This view also projects the ureter of the "down" side away from the spine to prevent superimposition. [17, 18]
ARRT - American Registry of Radiologic Technologists Thorax and Abdomen Procedures Questions and Answers
A patient is sent to radiology for a chest examination to rule out a small pneumothorax.
The patient is able to stand and cooperate.
In addition to the standard PA projection on full inspiration, which of the following would be most beneficial to demonstrate this condition?