Imaging

Question 1

Appropriateness of Imaging Scores

Answer 1

1-3 = not appropriate, 4-6 = may be appropriate, 7-9 = appropriate

Question 2

How does the heart look on a PA view, how do you deal with that?

Answer 2

Heart always looks bigger, always order a lateral view as well

Question 3

How is the quality of an oblique X-Ray?

Answer 3

Poor quality, can be used as a guide but not for dx

Question 4

ABCDEFGH Mneumonic for CXR

Answer 4

Airway, Bone and soft tissue, Cardiac Silhouette and Mediastinum, Diaphragm, Effusions/Extras (lines, tubes, devices, surgeries), Fields (lung), Gastric bubble, Hilum

Question 5

Fluoroscopy Uses

Answer 5

Functional information, PO contrast is required, evaluates the mucosa of the bowel

Question 6

Angiography Uses

Answer 6

Reveals veins and arteries

Question 7

Non-Contrast CT Uses

Answer 7

Evaluation of acute and subacute blood products, pre-surgical planning complex fractures, acute onset pain multi-joint arthropathy with no changes on plain radiographs, lung parenchyma, renal stones

Question 8

Does contrast effect the dose of radiation administered?

Answer 8

Yes, contrast absorbs radiation at a higher rate and more radiation must be administered

Question 9

What are the advantages of contrast?

Answer 9

Evaluation of solid organs and soft tissue

Question 10

Why would you use oral contrast?

Answer 10

Suspicion of bowel pathology, abcess or lymphadenoapthy

Question 11

When to use and avoid Gastrograpffin

Answer 11

More expensive, tastes terrible, can cause pneumonitis if aspirated, only used with suspected perforation

Question 12

Benefits of Barium over Gastrograpffin

Answer 12

Well tolerated, inexpensive, can cause peritonitis

Question 13

When would you use IV contrast

Answer 13

Evaluation of solid organs, vascular system, enhancement, patterns of masses, advanced function such as organ perfusion

Question 14

Definition of Contrast Nephropathy

Answer 14

0.5 mg or 25% increase in serum creatinine at 48-72 hours after exposure

Question 15

Risk Factors for Contrast Nephropathy

Answer 15

Cardiovascular disease, DM

Question 16

What do you have to test before you send a patient for a CT with contrast?

Answer 16

BUN and SCr

Question 17

Mild Contrast Rxn

Answer 17

Nausea, vomiting, urticaria, injection site warmth, injection site pain. Tx with observation 20-30 min

Question 18

Moderate Contrast Rxn

Answer 18

Hives, vasovagal rxn, bronchospasm, mild laryngeal edema. Tx Saline, oxygen, leg elevation, Diphenhydramine, beta agonists, epinephrine

Question 19

Severe Contrast Rxn

Answer 19

Severe bronchospasm, severe laryngeal edema, loss of consciousness, seizures, cardiac arrest. Tx life support equipment and CPR

Question 20

CT Pre-Imaging Allergy Treatment

Answer 20

Prednisone 50 mg at 13, 7 and 1 hour. Diphenhydramine 50 mg oral, IV or IM 1hr prior. Methylprednisolone 32 mg orally 12 and 2 hours prior - optional Benadryl

Question 21

Normal SCr

Answer 21

0.5 - 1.2 mg/dL

Question 22

Metformin

Answer 22

Hold for 48 hours AFTER the exam (some say 48 hours before as well)

Question 23

Nephrogenic Systemic Fibrosis

Answer 23

Vessels become fibrotic, no longer work. All vasculature in the kidney is scarred. Irreversible. Avoid MRI contrast if GFR <30

Question 24

When do you use High resolution CT?

Answer 24

Lung inflammation and scarring. Ex) Pulmonary fibrosis

Question 25

SOB after surgery think…?

Answer 25

Embolism

Question 26

What is the well’s Criteria used for?

Answer 26

Evaluating risk of DVT

Question 27

If you have a suspected PE with a wells score of <4

Answer 27

D-dimer assay. If it is normal, PE is excluded. If it is abnormal PE cannot be excluded, do CT with pulmonary angiography

Question 28

If you have a suspected PE with a wells score of >4

Answer 28

CT with pulmonary angiography

Question 29

Advantages of MRI

Answer 29

Excellent soft tissue contrast resolution, imagines in any plan, no radiation

Question 30

Limitations of MRI

Answer 30

No dense bone detail or calcification, limited resolution

Question 31

What is MRI the imaging of choice for?

Answer 31

Pelvic disease

Question 32

When do you need a contrast MRI?

Answer 32

Neoplastic lesions, vasculature (not blood flow), inflammatory or infectious processes

Question 33

Myelopathy

Answer 33

Cord compression - medical emergency, risk of paralysis

Question 34

When to use Ultrasound

Answer 34

Reproductive organs, peripheral venous and arterial, biliary system, fetal assessment, heart structure, renal stones, liver, spleen, pneumonia/pleural effusions

Question 35

PET scan isotope

Answer 35

Radioisotope 18-fluorodeogyglucose

Question 36

How does PET work?

Answer 36

FDG transported across cell membrane of actively metabolizing cells. Tumors are visualized because they have greater glucose metabolism

Question 37

Where do you see false positive PET?

Answer 37

Highly metabolic normal tissue (brain, bowel, GU, uterus)

Question 38

Where do you see false negative PET

Answer 38

Tumor <1cm, low metabolic tumors