Exam 2: Pulmonary Diagnostic Imaging

Question 1

What pulmonary diagnostic tests do not have any radiation?

Answer 1

US, MRI, and bronchoscopy

Question 2

What is the initial study to evaluate respiratory problems?

Answer 2

CXR

Question 3

What are the indications for CXR?

Answer 3

SOB, persistent cough, hemoptysis, chest pain, and fever

Question 4

What is an AP vs PA CXR view?

Answer 4

PA: beam coming from behind
AP: beam coming from front

Question 5

What is the systematic approach to reading a CXR

Answer 5

A: Airway
B: Bones
C: Cardiac silhouette
D: Diaphragms
E:Edges
F: Fields

Question 6

What is the apical lordotic view used for?

Answer 6

Potential TB

Question 7

What is Hampton’s hump?

Answer 7

A wedge shaped opacity seen on XR relegated to pulmonary infarct

Question 8

What is the radiation exposure of a CXR?

Answer 8

0.1 mSv

Question 9

What are the 5 different kinds of CT?

Answer 9

Conventional scan, helical CT, High resolution, low dose, and CT angiography

Question 10

What are the indications for a CT?

Answer 10

• To clarify an abnormal CXR
• Characterize pulmonary nodules
• assist in diagnosis of clinical signs/symptoms
• detection and staging of primary/metastatic lung neoplasms
• evaluate suspected mediastinal or hilar masses

Question 11

What is the radiation exposure of a CT?

Answer 11

~8mSv

Question 12

What two populations should you use caution when ordering a CT?

Answer 12

• Pediatrics (increased risk of brain tumor, leukemia, and radiation risk is compounded by longer lifespan)
• Pregnant women (in utero exposure linked to pediatric CA mortality, ALWAYS ASK LMP PRIOR TO IMAGING)

Question 13

What kind of contrast is used with CT?

Answer 13

Iodine contrast

Question 14

What is the purpose of contrast?

Answer 14

To enhance differences in densities of various structures

Question 15

When should you use contrast?

Answer 15

When evaluating vessels, malignancy, and trauma

Question 16

What are the risks associated with radiocontrast?

Answer 16

• Allergic reaction
• Contrast induced nephropathy
• Lactic acidosis if taking Metformin

Question 17

What are the symptoms of a contrast allergic reaction?

Answer 17

Flushing, pruritis, urticaria, angioedema, wheezing, anaphylaxis

Question 18

What are the risk factors for a contrast allergy?

Answer 18

A prior reaction, hx of asthma or atopy

**Shellfish allergy is NOT a contraindication!

Question 19

How should you pretreat a patient with a contrast allergy that you need a contrast CT for?

Answer 19

Pretreat with prednisone and Benadryl

Question 20

What is radiocontrast induced nephropathy?

Answer 20

An increase in serum creatinine >0.5 or >25% from baseline

Question 21

What are the creatinine and GFR levels in which you should not order a contrast CT?

Answer 21

If creatinine >1.5 or GFR < 60

Question 22

When should you check renal function prior to radiocontrast?

Answer 22

older than 60, history of renal disease, diabetes, HTN treated with medication, or taking metformin

Question 23

What modalities is pulmonary angiography used in conjunction with?

Answer 23

CTPA, direct pulmonary angiography, and pulmonary MRA

Question 24

What is used in detection of PE, aortic dissection, and SVC syndrome?

Answer 24

CTPA

Question 25

What is the radiation exposure from CTPA?

Answer 25

10-15 mSv

Question 26

What is the gold standard in evaluation of PE?

Answer 26

Catheter-directed pulmonary angiography

Question 27

When is catheter directed pulmonary angiography useful?

Answer 27

If V/Q scan or CTPA is inconclusive high there is high clinical suspicion of PE

Question 28

What are the risks associated with catheter-directed pulmonary angiography?

Answer 28

Bleeding or hematoma at insertion site, heart arrhythmia, allergic reaction, potential nephrotoxicity, and radiation exposure of 5mSv

Question 29

What kind of contrast is used in MRI?

Answer 29

Gadolinium

Question 30

What are V/Q scans used for?

Answer 30

Evaluation of pulmonary embolisms and for pre-op assessment prior to lung resection

Question 31

What makes the IV (perfusion) phase of a V/Q scan present?

Answer 31

Technetium 99 labeled to albumin

Question 32

What makes the inhalation (ventilation)phase present in a V/Q scan?

Answer 32

Radio-labeled xenon gas

Question 33

What is the test of choice for diagnosis of PE in pregnant women?

Answer 33

V/Q scan

Question 34

What are PET scans used for?

Answer 34

Mostly cancer, superior to CT for mediastinal imaging because it can identify tumors in normal sized lymph nodes

Question 35

How does a PET scan work?

Answer 35

Fluorodeoxyglucose (FGD) is a radioactive glucose that is injected into patient and it accumulates in tissues/organs with high metabolic activity and cancer cells have very high metabolic activity -Patient is scanned and measurements of the uptake are made in SUVs

Question 36

What SUV value from a PET scan raises possibility of malignancy?

Answer 36

SUV > 2.5

Question 37

When can a false negative occur in a PET scan? False positive?

Answer 37

False negative: slow growing tumors | False positive: can occur with inflammatory lesions/granulomas

Question 38

What are the indications for thoracic US?

Answer 38

- Bedside detection of pleural fluid, hemothorax, or pnuemothorax - Guidance of thoracentesis - guidance for placement of thoracostomy tubes

Question 39

What are the therapeutic uses of bronchoscopy?

Answer 39

Removal of excess mucous or FB, and ET tube placement