Intro to Labs and Panels & Diagnostic imaging DSA Flashcards

1
Q

What data is included in a CBC?

A
WBC count
Hgb
Hct
MCH
MCHC
MCV
RDW
RBC count
Platelet count (Plt)
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2
Q

What information is included on a CBC with differential that is not included in the regular CBC?

A

Percentage and absolute differential counts (PMN, lymph, baso, eos, mono, atypical mono)

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3
Q

What info is included in a BMP?

A
BUN
BUN:Cr ratio
Calcium
CO2
Chloride
Creatinine
eGFR
Glucose
Potassium
Sodium
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4
Q

What additional info is included on the CMP that is not included on the regular BMP?

A
Albumin:globulin ratio (A:G ratio)
Albumin (Alb)
Alkaline phosphatase (AP)
Aspartate aminotransferase (AST/SGOT)
Alanine aminotransferase (ALT/SGPT)
Bilirubin, total
Globulin, total
Protein, total
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5
Q

Describe US imaging

A

Uses high-frequency sound waves to generate an image, uses US coupling gel to aid in wave transmission to transducer

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6
Q

Pros and cons of ultrasound

A

Pros: no radiation, cheaper than other modalities, non-invasive

Cons: bowel gas and lung tissue hinder US image, technician skills vary, body habitus can affect results

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7
Q

Indications for US imaging

A
Trauma
RUQ pain
RLQ pain
Pregnancy
GU complaints
Acute pelvic pain
Cardiac concerns
Evaluate blood flow

Procedures — thoracentesis, pericardiocentesis, etc.

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8
Q

What is a FAST exam?

A

Focused Assessment with Sonography in Trauma

Rapidly assesses for free fluid in the body! — primary views are subxiphoid, RUQ, LUQ, suprpubic

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9
Q

Describe conventional x-ray

A

Patient placed between film cassette and X-ray machine

X-rays pass through body and become attenuated, having photochemical reaction with fluorescent coated film, light particles create image

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10
Q

Radiographic density interpretation of air, fat, soft tissue, mineral, and metal on x-ray

A

Air = black

Fat = dark gray

Soft tissue = light gray

Mineral = off white

Metal = bright white

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11
Q

Types of contrast used with x-ray

A

GI contrast — Barium and gastrograffin

Typically given PO or PR; radioopaque to visualize GI tract

Ideal to wait 45 min s/p ingestion for best visualization

Adverse effects are minimal — N/V/diarrhea/constipation

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12
Q

Pros and cons of x-ray

A

Pros: cheap, easily accessible, fast, excellent screening tool, widely available

Cons: 2D pic, radiation exposure, poor detail of soft tissue

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13
Q

Uses indicated for x-ray

A
Cardiovascular
Pulmonary
Musculoskeletal
Gastrointestinal
Dental
Mammogram
Line and tube assessment
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14
Q

Modality that uses continually emitted x-rays and allows for real time visualization, but images are intensified with reduced radiation exposure and attenuation is different than conventional xray

A

Fluoroscopy

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15
Q

Uses for fluoroscopy

A
Esophagram
Upper GI study
Small bowel follow-through
Barium enema
Cardiac
Vascular
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16
Q

Pros and cons of CT

A

Pros: widely available, quick, painless, somewhat reasonable price, 3D image in cross-section

Cons: potential contrast reaction, exposure to radiation, diagnosis limitations

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17
Q

Type of contrast utilized in CT, and why it is used

A

IV iodinated contrast — given IV or intra-arterial (opacifies vessel lumen)

Used because it increases attenuation compared to the anatomical structures that surround it (enhances visibility of internal structures)

Best uses: vessels, visualize tissue changes, urinary tract, fallopian tubes, etc.; neuro — veno/angiogram, abscess, malignancy

18
Q

When would you NOT use contrast with CT?

A

If you’re suspicious of a bleed, renal stone, retroperitoneal hematoma — contrast might block your view of the bleed/stone

19
Q

CT uses in Neuro, pulm, GI systems

A

Neuro: HA, trauma, r/o bleeds, CVA sxs, seizure

Pulm: acute SOB, CP w/ radiation to back, assess nodules/masses

GI: explore etiology of abdominal/pelvic pain, r/o renal stone, r/o GI path

[these are not all encompassing]

20
Q

MRI basics

A

Use of magnetic field to generate image — manipulation of polarity of H+ atoms

Tissues generate different signals based on H+ composition giving GREATER DETAIL OF SOFT TISSUES

21
Q

Define T1 vs. T2 images in MRI

A

T1 (longitudinal relaxation time) — time it takes for excited protons to return to equilibrium; contrast used

T2 (transverse relaxation time) — determines rate at which excited protons reach equilibrium or go out of phase with each other

22
Q

Preferred contrast agent in MRI

A

Gadolinium

Administered via IV — tremendous paramagnetic properties

Used during T1 weighted imaging to improve visability of inflammation, tumors, blood vessels, organs, blood supply, etc.

Generally well tolerated with minimal SEs; reactions uncommon

23
Q

When would you use T1 vs T2 imaging for MRI?

A

T1 — anatomy (anatomical details, fat containing structures, subacute hemorrhages). Water and collagenous tissue (ligaments, tendons, scars) have a lower signal transduction on T1 weighted image

T2 — pathology (edema, tumor, infarction, hemorrhage). Characteristic of T2 is high signal intensity of water. Pathology is often associated with edema/fluid, thus T2 is utilized in these cases

24
Q

When should you use caution when selecting MRI?

A

Cardiovascular devices — pacemakers, stents, mechanical valves, IVC filters, etc

Unstable patients

Claustrophobic or agitated pts

Large body habitus

25
Q

Cautionary considerations with Gadolinium contrast

A

Contrast induced nephropathy — can occur w/i 24-48 hrs of administration; characterized by increased serum Cr, decreased GFR with oliguria (<500mL UOP/day)

Nephrogenic systemic fibrosis — get pre-contrast GFR measurement

Advanced renal failure or dialysis pts (GFR <30mL)

26
Q

Symptoms of nephrogenic systemic fibrosis induced by gadolinium

A

Thickening and harding of skin (spares the head); mimics scleroderma!

Also causes fibrosis of internal organs; stiffens extremities; flexion contractures

27
Q

Pros vs. cons of MRI

A

Pros: safe, no radiation, precise with incredible detail of soft tissue

Cons: not widely available, costly, body habitus, pt must have extreme patience (takes 30-90 mins)

28
Q

Define and note types of angiography

A

Injection of contrast media directly into artery or vein via needle or catheter

Invasive: percutanous (think cardiac cath lab - fluoroscopy)

Can also be non-invasive: CT or MRI

29
Q

5 most important diagnostic imaging considerations when choosing a modality

A
  1. Safety
  2. Cost
  3. Availability
  4. Contrast vs. none
  5. Patient comorbidities
30
Q

Deterministic (acute) and stochastic (chronic) effects of radiation exposure

A

Acute = burns, sterility, radiation sickness

Chronic = cancer, hereditary

31
Q

Children, young adults, and women of reproductive age are at greatest risk with radiation exposure. What is an important consideration from this group?

A

Get B-hCG on reproductive age females!

32
Q

The Law of Bergonie and Tribondeau states that the cells most sensitive to radiation have what 3 characteristics?

A

Rapidly dividing

Undifferentiated

Have long mitotic future

[high sensitivity = lymphoid organs, bone marrow, testes, ovaries, small intestines; fairly high = skin, cornea, lens, GI organs including esophagus, stomach, rectum; medium = growing cartilage, vasculature, growing bones]

33
Q

What type of imaging has the highest radiation exposure potential?

A

Interventional fluoroscopy

[in order of increasing exposure: dental xray < CXR < mammography < CT < Nuclear medicine < interventional fluoroscopy]

34
Q

What is PACS?

A

Picture archiving communication system

Allows you to look at and share previous imaging between providers

35
Q

Contrast and radiation considerations in special populations

A

Previous allergy to contrast

Renal patients with creatinine > 1.5

Female pts — get B-HCG

Pregnant pts — don’t do contrast or radiation during days 16-45 bc critical for fetal dev’t

Children

Medications

36
Q

What medication should you advise pts to withold prior to imaging with contrast d/t risk of lactic acidosis?

A

Metformin

37
Q

Types of contrast reactions

A
  1. Hypersensitivity reactions — hives, anaphylaxis, urticaria, pruritis, angioedema; can be immediate or delayed. Pretreat w/ prednisone w/ diphenhydramine. Rapid tx is epi + saline +/- albuterol prn
  2. Chemotoxic reactions — self-limited; n/v, flushing
  3. Vasovagal reactions — increased vasovagal tone —> decreased SA and AV node conduction
38
Q

You are seeing a pt and you suspect MS, what type of imaging would you do?

A

MRI

T1 — shows heterogeneity in white matter tracts

T2 — shows deep white matter demyelinating foci, with predominantly periventricular location — confirms MS

39
Q

80 y/o male brought to ED after being found on floor; GCS is 10 and he is on warfarin. What type of imaging do you do?

A

CT w/o contrast

40
Q

77 y/o male with acute change in alertness. What type of imaging?

A

CT w/o contrast

41
Q

26 y/o female presents with neck pain s/p MVA. Denies weakness, numbness, tingling, UE pain, HA. What imaging do you do?

A

X-ray of neck - frontal and lateral

Get HCG first!