URS752 Exam 2 Master Guide | 135 Key
N
Concepts with Verified Answers | 2025
Edition
I.Diagnostic Imaging: X-ray, CT, and MRI
A. Chest X-ray (CXR)
1. Reasons to order an X-ray:Infection, dyspnea, chest pain, trauma,
hemoptysis, suspected mass.
2. Densities visible on X-ray:Air, fat, water (soft tissue), bone, and metal.
3. Appearance of air on X-ray:Blackest – less dense.
4. CXR findings in Emphysema or COPD exacerbation:Hyperinflated lungs
with flattened diaphragm and coarse bronchovascular markings.
5. CXR findings in Pneumonia:Ground glass opacities.
6. Normal Cardio-Thoracic Ratio (CTR):< 1:2.
7. Most dense structures on a normal X-ray:Bones.
8. Assessing adequacy of inspiration on CXR:Clavicle and ribs are
landmarks.
, <5 ribs = incomplete inspiration.
○
○ 7 ribs = hyperexpansion.
9. Checklist for reading X-ray:Heart (silhouette sign), mediastinum,
diaphragm, lungs, skeleton.
10. When radiological investigation is generally not warranted:
Uncomplicated URI, asthma, minor trauma.
11.Three criteria for determining quality of a chest X-ray:Rotation,
inspiration, and penetration.
B. Computed Tomography (CT)
1. Reasons to order a CT:X-ray and exam inconclusive; ongoing disease
process without clear diagnosis. Can detect conditions like PE, lung
masses, and aid in tumor staging due to better visualization of structures,
soft tissues, and vessels than X-ray.
2. Special considerations for CT:
○ High-resolution scan is best for interstitial lung diseases like pulmonary
fibrosis.
○ Consider CT pulmonary angiography when ruling out PE.
○ Contrast scans are preferred but contraindicated in renal impairment
and allergies.
3. Initial evaluation of trauma or hemorrhage (CT vs. MRI):CT without
contrast.
C. Magnetic Resonance Imaging (MRI)
. Does MRI use ionizing radiation?No.
1
2. Advantages of MRI:No ionizing radiation, high-quality image produced,
distinguishes between different types of soft tissue, not impeded by bone,
no known side effects, many details without contrast.
3. Disadvantages of MRI:High costs, longer scanning times than CT, cannot
be used in people with implanted metal devices, not widely available, many
exclusions, requires protocol sequence.
4. Evaluation of infection, inflammation, malignancy, seizure (CT vs.
MRI):MRI with and without contrast.
D. Lung Anatomy
1. Lung with 3 lobes:Right lung.
N
Concepts with Verified Answers | 2025
Edition
I.Diagnostic Imaging: X-ray, CT, and MRI
A. Chest X-ray (CXR)
1. Reasons to order an X-ray:Infection, dyspnea, chest pain, trauma,
hemoptysis, suspected mass.
2. Densities visible on X-ray:Air, fat, water (soft tissue), bone, and metal.
3. Appearance of air on X-ray:Blackest – less dense.
4. CXR findings in Emphysema or COPD exacerbation:Hyperinflated lungs
with flattened diaphragm and coarse bronchovascular markings.
5. CXR findings in Pneumonia:Ground glass opacities.
6. Normal Cardio-Thoracic Ratio (CTR):< 1:2.
7. Most dense structures on a normal X-ray:Bones.
8. Assessing adequacy of inspiration on CXR:Clavicle and ribs are
landmarks.
, <5 ribs = incomplete inspiration.
○
○ 7 ribs = hyperexpansion.
9. Checklist for reading X-ray:Heart (silhouette sign), mediastinum,
diaphragm, lungs, skeleton.
10. When radiological investigation is generally not warranted:
Uncomplicated URI, asthma, minor trauma.
11.Three criteria for determining quality of a chest X-ray:Rotation,
inspiration, and penetration.
B. Computed Tomography (CT)
1. Reasons to order a CT:X-ray and exam inconclusive; ongoing disease
process without clear diagnosis. Can detect conditions like PE, lung
masses, and aid in tumor staging due to better visualization of structures,
soft tissues, and vessels than X-ray.
2. Special considerations for CT:
○ High-resolution scan is best for interstitial lung diseases like pulmonary
fibrosis.
○ Consider CT pulmonary angiography when ruling out PE.
○ Contrast scans are preferred but contraindicated in renal impairment
and allergies.
3. Initial evaluation of trauma or hemorrhage (CT vs. MRI):CT without
contrast.
C. Magnetic Resonance Imaging (MRI)
. Does MRI use ionizing radiation?No.
1
2. Advantages of MRI:No ionizing radiation, high-quality image produced,
distinguishes between different types of soft tissue, not impeded by bone,
no known side effects, many details without contrast.
3. Disadvantages of MRI:High costs, longer scanning times than CT, cannot
be used in people with implanted metal devices, not widely available, many
exclusions, requires protocol sequence.
4. Evaluation of infection, inflammation, malignancy, seizure (CT vs.
MRI):MRI with and without contrast.
D. Lung Anatomy
1. Lung with 3 lobes:Right lung.
