Pulmonary Dx Imaging Flashcards
(71 cards)
1
Q
Imaging w/o radiation
A
U/s, MRI/MRA, Bronchoscopy
2
Q
initial study for respiratory sx
A
CXR
3
Q
What structures does CXR show
A
lung parenchyma, pleura, chest wall, diaphragm, mediastinum, hilum
4
Q
Color of CXR
A
gas = black fat = dark gray soft tissue = light gray bone calcification = nearly white metal = white
5
Q
Indications for CXE
A
SOB persistent cough hemoptysis chest pain/injury fever
6
Q
CXR views
A
PA, AP, lateral, decubitus (PA and lateral are main ones; AP only done when patient can’t get out of bed – makes structures look bigger than they actually are)
7
Q
ABCDEF’s of CXR
A
Airway Bone Cardiac Diaphragm Edges Fields of lungs
8
Q
Lateral view CXR
A
good for seeing lower lobes
9
Q
apical lordotic view use
A
seeing something in apex of lung (ex. TB)
10
Q
PA and lateral decubitus CXR use
A
determine pus vs. fluid (fluid moves b/c it is free flowing) – subpulmonic effusion
11
Q
Benefits of CXR
A
non-invasive low radiation inexpensive convenient widely available
12
Q
Pulmonary infarct
A
“Hampton’s hump”
triangular shape w/ base along chest wall; clot causes loss of circultation in lung leading to infarct
13
Q
Risks/limitations of CXR
A
radiation exposure
pregnancy
can’t detect some conditions (small cancers, pulmonary emboli)
14
Q
Why order a CT?
A
clarify abnormal CXR dx clinical sx (SOB, cough, CP, fever) characterize pulmonary nodules detect and stage primary and metastatic neoplasms lung cancer screening evaluate mediastinal or hilar masses
15
Q
Lung cancer screening
A
55-80 yo w/ 30 pack/yr hx and currently smoke OR quit w/i past 15 years
16
Q
Types of CT scans
A
conventional helical high resolution (HRCT) low dose CT CT angiography
17
Q
conventional CT
A
10 mm slice
“step and shoot”; 25-30 min
18
Q
Helical CT
A
aka spiral CT
faster
continuous
<5 min
19
Q
HRCT
A
better detail, 1 mm slice
20
Q
Low dose CT
A
used for screening, less detail
21
Q
Multidetector/multislice CT
A
64 x faster, but higher radiation
22
Q
Benefits of CT
A
fast, widely available detailed images real-time imaging for bx can be performed w/ implanted device less expensive and sensitive to movement than MRI
23
Q
Risk/limitations of CT
A
Radiation exposure increased CA risk fetal exposure during pregnancy contrast issues body habitus >450 lbs
24
Q
Special populations for CT
A
peds: more radiosensitive, increased risk of leukemia and brain tumors
pregos: in utero exposure linked to ped CA mortality (always ask LMP before imaging)
25
CT contrast
iodine
26
Goal of contrast
enhance differences in densities of various structures
27
When to use contrast?
masses, CA, metastatic, obstructive processes, PE or dissection
28
Non-contrast use
eval of diffuse lung disease (HRCT)
| follow up of primary nodules
29
Risk of CT w/ contrast
allergic rxn
contrast induced nephropathy
lactic acidosis if taking glucophage (metformin) -- hold 48 hrs after imaging
30
Allergic rxn from contrast
develops 5-60 min after
| flushing, pruritus, urticaria, angioedema, bronchospasm, and wheezing, stridor, HTN, loss of consciousness
31
Risk factor for allergic rxn to contrast
prior rxn
asthma
atopy
32
How to avoid contrast rxn
pre-treat w/:
| Prednisone & Diphenhydramine (Benadryl)
33
Contrast induced nephropathy
serum Cr >25% from baseline or >0.5 mg/dL
usually reversible
Caution using contrast in pts w/ impaired kidney function
34
Impaired kidney function considered
Cr >1.5 or GFR <60
35
When to check renal function before iodine contrast
```
age >60
hx of renal disease (dialysis, single kidney, kidney transplant, renal cancer, renal surgery)
HTN treated w/ meds
DM
Glucophage (metformin)
```
36
Glucophage
eGFR >30 - med doesn't need to be withheld
AKI or severe CKD w/ eGFR <30 - hold metformin x 48 hrs; resume after eval of renal funciton (avoiding lactic acidosis)
37
Pulmonary Angiography types
CTA or direct pulmonary angiography (catheter into patients)
38
Angiography use
assess vasculature; done w/ CT, MRI or X-ray (direct)
39
CTA
blood vessel detail; used for suspected PE, aortic dissection , SVC syndrome
identify vascular malformations
assess pulmonary arterial invasion by neoplasm
40
CTPA benefits
less invasive than direct
precise anatomical guidance if surgery warranted
safer than conventional angiography
41
Risks/limitations of CTPA
```
can miss sub-segmental PES
allergy to contrast
nephrotoxicity
radiation
body habitus >450 lbs
```
42
Gold standard for PE
direct pulmonary angiography
43
What is direct pulmonary angiography?
needle/catheter inserted into right femoral or internal jugular vein --> R side heart --> pulm arteries
dye injected, x-rays taken
44
When do you use direct pulmonary angiography
if V/Q or CTPA inconclusive but still have high clinical suspicion
45
Risk of direct pulmonary angiography
```
bleeding/hematoma at insertion site
heart arrhythmia
allergic rxn to contrast
impaired kidney function
radiation
```
46
MRI use
limited in pulm disease
hilar or mediastinal densities, sulcus tumors, cysts, lesions of chest wall
if patient has allergy to iodine or renal disease (GFR <60)
47
Benefits of MRI
no bone artifact as w/ CT
| no radiation
48
Contrast for MRI
gadolinium
49
Limitations of MRI/MRA
pt must remain still
clautrophobia
body habitus
risk of nephrogenic systemic fibrosis (irreversible) - avoid gadolinium if GF <30 ml/min
50
Contraindications of MRI/MRA
pacemaker/defibrillator
metal in eye
aneurysm clip
cochlear implant
51
Nuclear imaging types
VQ
| PET scan
52
VQ use
PE
| pre-op assessment prior to lung resection
53
VQ mismatch
imbalance of blood flow and ventilation
54
V/Q scan phases
IV phase: tech-99m (labeled to human albumin) injected and follows blood flow (perfusion)
inhalation phase: radio-labeled xenon gas demonstrates distribution of ventilation
55
Benefits of V/Q
allergic rxn to radiopharm is rare
low dose radiation
Test of choice for PE in pregnant women
useful in estimating postop reserve capacity for those undergoing lung resection
56
TOC for PE in pregos
V/Q
57
Limitations of V/Q scan
sensitive for PE, but poorly specific (high false positives)
best utilized in those w/ normal CXR
no absolute contraindications
58
PET scan
physiologic images
| radiation emitted from fluorodeoxyglucose (FDG)
59
FDG
radioactive glucose
| accumulates in tissues/organs w/ high metabolic activity (cancer cells)
60
measurement of PET scan
SUV >2.5 raises probability of malignancy
61
Use of PET scan
detect cancer
metastasis
examine effects of cancer therapy
62
Benefits of PET scan
detect changes in anatomy before apparent w/ CT and MRI
| radioactivity is short-lived
63
Limitations of PET scan
radiation
false + (inflammatory lesions, granulomas)
false - w/ slow growing tumors
time sensitive - radioactive substance decays quickly
high cost
64
Indications for U/S
bedside detection of pleural fluid or pneumothorax
guidance for thoracentesis
guidance for placement of thoracostomy tubes
65
Benefits of u/s
no radiation
| portable units
66
u/s of normal lung
seashore sign
67
barcode or stratosphere sign
pneumothorax (no motion lung)
68
Broncoscopy indications
```
pneumonia, hemoptysis, cough
dx tracheoesophageal fistulas and tracheobronchomalacia
tissue sampling
removal of excess mucus or FBs
ET tube placement
```
69
Rigid bronchoscopy
used for pts w/ obstruction of trachea or a proximal bronchus; for removal of debris (FB)
70
Benefits of bronchoscopy
```
safe
low complications (nasal discomfort, sore throat, mild hemoptysis; hemorrhage, pneumothorax, Hypotension, arrhythmia)
```
71
Contraindications for bronchscopy
severe refractory hypoxia
risk of bleeding (anticoagulants, coagulopathy)
risk of respiratory and CV decompensation (asthma or COPD exacerbation current or recent MI, poorly controlled CHF, life threatening arrhythmias)
