NBCE PART III DIAGNOSTIC
IMAGING (DXI) EXAM 2026/2027 –
150 PRACTICE QUESTIONS WITH
ANSWERS & RATIONALES |
CHIROPRACTIC RADIOLOGY BOARD
REVIEW
1. Which of the following is the primary mechanism by which x-rays interact
with matter to produce the diagnostic image?
A) Coherent scattering
B) Photoelectric absorption and Compton scattering
C) Pair production
D) Nuclear photodisintegration
Answer: B
Rationale: At diagnostic energies (roughly 20–150 kVp), photoelectric effect and
Compton scatter dominate. Pair production requires >1.02 MeV and is irrelevant
diagnostically.
2. The ALARA principle in radiography is best described as:
A) Using the highest possible mAs for image quality
B) Keeping radiation dose As Low As Reasonably Achievable
C) Avoiding all radiographs in pregnancy
D) Using fluoroscopy instead of plain film
Answer: B
Rationale: ALARA is a fundamental radiation-protection principle emphasizing dose
minimization while maintaining diagnostic adequacy.
,3. Which collimation change will most reduce patient dose without degrading
diagnostic quality?
A) Increasing field size to include the whole torso
B) Tight collimation to the region of interest
C) Removing the grid
D) Increasing kVp by 30%
Answer: B
Rationale: Restricting the beam to the area of interest reduces irradiated volume and
scatter, lowering dose.
4. On a lateral cervical spine radiograph, which structure is used to assess for
anterior atlantoaxial subluxation?
A) Spinolaminar line
B) Predental space (atlantodental interval)
C) Posterior cervical line
D) McRae's line
Answer: B
Rationale: The atlantodental interval (predental space) >3 mm in adults (or >5 mm in
children) suggests instability/subluxation.
5. A "step-off" of the anterior vertebral body line on a lateral lumbar film most
suggests:
A) Compression fracture or subluxation
B) Normal variant
C) Spina bifida occulta
D) Osteopoikilosis
Answer: A
Rationale: Disruption of the anterior vertebral line indicates malalignment—fracture,
dislocation, or listhesis.
6. Which arthritis classically shows marginal erosions with periarticular
osteopenia and symmetric MCP/PIP involvement?
,A) Osteoarthritis
B) Rheumatoid arthritis
C) Psoriatic arthritis
D) Diffuse idiopathic skeletal hyperostosis (DISH)
Answer: B
Rationale: RA is symmetric, erosive, with periarticular osteopenia and marginal
erosions; OA shows joint-space narrowing with osteophytes and sclerosis.
7. "Bamboo spine" on radiographs is most characteristic of:
A) Ankylosing spondylitis
B) Degenerative disc disease
C) Paget disease
D) Metastatic disease
Answer: A
Rationale: AS produces syndesmophytes bridging vertebral bodies, giving the
bamboo-spine appearance.
8. A lytic lesion with a "soap-bubble" appearance in the epiphysis of a young
patient most suggests:
A) Osteosarcoma
B) Giant cell tumor
C) Ewing sarcoma
D) Osteoid osteoma
Answer: B
Rationale: Giant cell tumor is classically epiphyseal/metaphyseal, lytic, expansile, in
skeletally mature young adults.
9. Sunburst periosteal reaction with Codman triangle is most suggestive of:
A) Osteosarcoma
B) Osteochondroma
C) Enchondroma
D) Bone cyst
, Answer: A
Rationale: Aggressive periosteal reaction (sunburst, Codman triangle) with a
destructive lesion suggests osteosarcoma.
10. Which imaging modality is first-line for suspected acute lumbar disc
herniation with neurologic deficit?
A) Plain radiography
B) MRI
C) CT without contrast
D) Bone scan
Answer: B
Rationale: MRI is the modality of choice for soft-tissue disc pathology and nerve root
evaluation.
11. The "winking owl" sign on AP lumbar radiograph indicates:
A) Missing pedicle (possible metastasis)
B) Fractured transverse process
C) Normal facet joint
D) Spondylolisthesis
Answer: A
Rationale: Loss of a pedicle's cortical outline ("winking owl") raises concern for lytic
metastasis.
12. Which view best demonstrates the odontoid process?
A) AP lower cervical
B) Open-mouth odontoid view
C) Swimmer's view
D) Lateral thoracic
Answer: B
Rationale: The open-mouth view visualizes the dens and lateral masses of C1.
IMAGING (DXI) EXAM 2026/2027 –
150 PRACTICE QUESTIONS WITH
ANSWERS & RATIONALES |
CHIROPRACTIC RADIOLOGY BOARD
REVIEW
1. Which of the following is the primary mechanism by which x-rays interact
with matter to produce the diagnostic image?
A) Coherent scattering
B) Photoelectric absorption and Compton scattering
C) Pair production
D) Nuclear photodisintegration
Answer: B
Rationale: At diagnostic energies (roughly 20–150 kVp), photoelectric effect and
Compton scatter dominate. Pair production requires >1.02 MeV and is irrelevant
diagnostically.
2. The ALARA principle in radiography is best described as:
A) Using the highest possible mAs for image quality
B) Keeping radiation dose As Low As Reasonably Achievable
C) Avoiding all radiographs in pregnancy
D) Using fluoroscopy instead of plain film
Answer: B
Rationale: ALARA is a fundamental radiation-protection principle emphasizing dose
minimization while maintaining diagnostic adequacy.
,3. Which collimation change will most reduce patient dose without degrading
diagnostic quality?
A) Increasing field size to include the whole torso
B) Tight collimation to the region of interest
C) Removing the grid
D) Increasing kVp by 30%
Answer: B
Rationale: Restricting the beam to the area of interest reduces irradiated volume and
scatter, lowering dose.
4. On a lateral cervical spine radiograph, which structure is used to assess for
anterior atlantoaxial subluxation?
A) Spinolaminar line
B) Predental space (atlantodental interval)
C) Posterior cervical line
D) McRae's line
Answer: B
Rationale: The atlantodental interval (predental space) >3 mm in adults (or >5 mm in
children) suggests instability/subluxation.
5. A "step-off" of the anterior vertebral body line on a lateral lumbar film most
suggests:
A) Compression fracture or subluxation
B) Normal variant
C) Spina bifida occulta
D) Osteopoikilosis
Answer: A
Rationale: Disruption of the anterior vertebral line indicates malalignment—fracture,
dislocation, or listhesis.
6. Which arthritis classically shows marginal erosions with periarticular
osteopenia and symmetric MCP/PIP involvement?
,A) Osteoarthritis
B) Rheumatoid arthritis
C) Psoriatic arthritis
D) Diffuse idiopathic skeletal hyperostosis (DISH)
Answer: B
Rationale: RA is symmetric, erosive, with periarticular osteopenia and marginal
erosions; OA shows joint-space narrowing with osteophytes and sclerosis.
7. "Bamboo spine" on radiographs is most characteristic of:
A) Ankylosing spondylitis
B) Degenerative disc disease
C) Paget disease
D) Metastatic disease
Answer: A
Rationale: AS produces syndesmophytes bridging vertebral bodies, giving the
bamboo-spine appearance.
8. A lytic lesion with a "soap-bubble" appearance in the epiphysis of a young
patient most suggests:
A) Osteosarcoma
B) Giant cell tumor
C) Ewing sarcoma
D) Osteoid osteoma
Answer: B
Rationale: Giant cell tumor is classically epiphyseal/metaphyseal, lytic, expansile, in
skeletally mature young adults.
9. Sunburst periosteal reaction with Codman triangle is most suggestive of:
A) Osteosarcoma
B) Osteochondroma
C) Enchondroma
D) Bone cyst
, Answer: A
Rationale: Aggressive periosteal reaction (sunburst, Codman triangle) with a
destructive lesion suggests osteosarcoma.
10. Which imaging modality is first-line for suspected acute lumbar disc
herniation with neurologic deficit?
A) Plain radiography
B) MRI
C) CT without contrast
D) Bone scan
Answer: B
Rationale: MRI is the modality of choice for soft-tissue disc pathology and nerve root
evaluation.
11. The "winking owl" sign on AP lumbar radiograph indicates:
A) Missing pedicle (possible metastasis)
B) Fractured transverse process
C) Normal facet joint
D) Spondylolisthesis
Answer: A
Rationale: Loss of a pedicle's cortical outline ("winking owl") raises concern for lytic
metastasis.
12. Which view best demonstrates the odontoid process?
A) AP lower cervical
B) Open-mouth odontoid view
C) Swimmer's view
D) Lateral thoracic
Answer: B
Rationale: The open-mouth view visualizes the dens and lateral masses of C1.
