ARRT Spine and Pelvis Procedures 2 — Questions and Answers
Question 1: Which projection best demonstrates the zygapophyseal joints of the lumbar spine on the side closest to the image receptor?
- AP projection
- Lateral projection
- 45-degree oblique projection (Correct answer)
- Axial projection
Correct answer: 45-degree oblique projection
A 45-degree oblique projection of the lumbar spine demonstrates the zygapophyseal joints on the side closest to the IR (downside joints on RPO/LPO).
Question 2: For a lateral projection of the sacrum, the central ray is directed:
- Perpendicular to the IR (Correct answer)
- 15 degrees cephalad
- 15 degrees caudad
- 5 degrees cephalad
Correct answer: Perpendicular to the IR
For a lateral sacrum projection, the central ray is directed perpendicular to the IR, centered to the sacrum at the level of the ASIS.
Question 3: The 'Scottie dog' appearance seen on oblique lumbar spine images represents which anatomical structures?
- Vertebral bodies and intervertebral discs
- Pedicles, transverse processes, and articular processes (Correct answer)
- Spinous processes and laminae
- Intervertebral foramina and nerve roots
Correct answer: Pedicles, transverse processes, and articular processes
The 'Scottie dog' silhouette on oblique lumbar images is formed by the pedicle (eye), transverse process (nose), superior articular process (ear), inferior articular process (front leg), and pars interarticularis (neck).
Question 4: Which centering point is used for the AP projection of the sacroiliac joints?
- At the level of the ASIS
- 1 inch superior to the pubic symphysis
- 2 inches superior to the pubic symphysis and 2 inches lateral to midline (Correct answer)
- At the level of the iliac crests
Correct answer: 2 inches superior to the pubic symphysis and 2 inches lateral to midline
For AP oblique projections of the sacroiliac joints, the CR is directed to a point 1 inch medial to the elevated ASIS, approximately 2 inches superior to the symphysis pubis.
Question 5: When performing a lateral projection of the cervical spine, what is the minimum SID recommended to reduce magnification?
- 40 inches (100 cm)
- 48 inches (120 cm)
- 60 inches (152 cm)
- 72 inches (183 cm) (Correct answer)
Correct answer: 72 inches (183 cm)
A 72-inch (183 cm) SID is recommended for lateral cervical spine projections to reduce magnification caused by the large OID between the neck and the IR.
Question 6: For an AP axial projection of the dens (open-mouth odontoid), if the patient cannot open their mouth sufficiently, which alternative method may be used?
- Fuchs method
- Judd method
- Ottonello method (Correct answer)
- Grandy method
Correct answer: Ottonello method
The Ottonello method uses tomography or a slow breathing technique with the mouth closed to blur overlying structures and demonstrate the dens.
Question 7: Which SID and CR angle are used for the AP axial projection of the lumbar spine to demonstrate the intervertebral disc spaces?
- 40 inches, 30-35 degrees cephalad
- 40 inches, 30-35 degrees caudad
- 40 inches, 5-8 degrees cephalad (Correct answer)
- 72 inches, perpendicular
Correct answer: 40 inches, 5-8 degrees cephalad
For AP axial lumbar intervertebral disc spaces, a 40-inch SID with 5-8 degrees cephalad CR angulation opens the disc spaces more effectively.
ARRT Spine and Pelvis Procedures 2
Which projection best demonstrates the zygapophyseal joints of the lumbar spine on the side closest to the image receptor?