L9 Pulmonary diagnostics Flashcards
3 imaging methods that don’t use ionizing radiation
Ultrasound
MRI/MRA
Bronchoscopy
Indication for CXR
SOB Persistent cough Hemoptysis Chest pain or injury Fever
CXR views
PA, AP, lateral, decubitius, apical lordotic
ABCDE of CXR
Airway Bones Cardiac Diaphragm Edges
Xrays can miss
very small cancers
pulmonary emboli
CT is good for
clarifying an abnormal CXR diagnose cause of clinical s/sx characterize pulmonary nodules staging of primary and metastatic lung neoplasms evaulate mediastinal or hilar masses
who to screen for lung cancer
55-80 years old with a 30 pack year history and currently smoke or quit within past 15 years
conventional CT is done
step and shoot, takes 25-30 mins
helical CT is done
continuously, <5 min
high resolution CT has slices that are
<1 mm
CT that is used for screening and has less detail
low dose CT
type of CT that can be done conventional or helical, is 64x faster, but has much higher radiation
multidectector or multislice CT
what to use if a patient has an implanted device
CT
real-time imaging for biopsies
CT
issues with CT
increased cancer risk
Body habitus >450 lbs
pediatric risks with CT scans
leukemia and brain tumors
pregnancy risks with CT scans
in utero exposure linked to pediatric cancer mortality
whatcha gotta ask before exposing a patient to radiation
LMP!!!!!!!!!
contrast used in CT
iodine
what’s well seen on CT with contrast
blood vessels encases by a tumor constricting it
CT with contrast is good for
Masses Cancer Metastatic disease Obstructive processes PE
CT w/o contrast is good for
follow up of known pulmonary nodules
High resolution CT is good for
evaluation of diffuse lung disease
Risk factors for allergic reaction to CT with contrast
prior reaction, asthma, atopy
shellfish allergy NOT A RISK FACTOR
pretreat allergy to CT with contrast with
Prednisone and diphenhydramine
contrast induced nephropathy is defined as
serum creatinine > 25% from baseline
-or-
>.5 mg/dL
caution using contrast in patients with
impaired kidney function: Creat >1.5 mg/dL or GFR <60
alternatives to CT with contrast in patients with impaired kidney function
CT w/o contrast
MR w/o gadolinium
U/S
Who to check renal function in prior to iodine contrast
>60 History of renal disease history of htn (treated) DM taking glucophage
who can take glucophage and still get a CT with contrast
eGFR > 30 ml/min
who shouldn’t take their glucophage when getting a CT with contrast
acute kidney injury
severe CKD with eGFR <30 ml/min
if you’ve held metformin to do a CT and it’s been 48 hours, your next step is to
re-evaluate renal function before resuming doses
angiography can be performed in conjunction with
CT (CTA)
MRI (MRA)
Xray with catheter
use CT pulmonary angiography if you suspect
pulmonary embolism
aortic dissection
superior vena cava syndrome
CT pulmonary angiography can assess
vascular malformations
pulmonary arterial invasion by a neoplasm
CT pulmonary angiography use in surgery
provides precise anatomical guidance
CT pulmonary angiography can miss
sub-segmental PEs
the gold standard in evaluation of PE is
Direct pulmonary angiography (Catheter directed)
when is a direct pulmonary angiography used
if a V/Q or CTPA is inconclusive and there is still a high clinical suspicion
risks of direct pulmonary angiography
Bleeding
Hematoma
Heart arrhythmia
(allergy, impaired kidney function, radiation)
direct pulmonary goes through the ____ to reach the ______ and then the ________
veins (femoral, internal jugular)
right side of the heart
pulmonary arteries
indications for MRI, which has limited usefulness in pulmonary disease
hilar/mediastinal densities
sulcus tumors
possible cysts/lesions of the chest wall
Benefits to MRI
no bone artifact (like CT)
no ionizing radiation
contrast material used in MRI/MRA
gadolinium
MR angiography provides
high quality images of blood vessels
compared to a CT chest, an MRI is
less detailed view of lung parenchyma
dimished spacial resolution
what kind of kidney damage can gadolinium cause
Nephrogenic systemic fibrosis
IRREVERSIBLE
In a patient with GFR<30 ml/min and MRI
avoid use of gadolinium
Contraindications of MRI/MRA
********************* Pacemaker/defibrillator metal in eye aneurysm clip cochlear implant **********************
Ventilation perfusion scans are used for
evaluate for PE
pre-op assessment prior to lung resection
V/Q mismatch means
imbalance of blood flow and ventilation
V/Q radiation is captured
by gamma cameras in 2 phases
contrast injected in V/Q during the IV phase
demonstrates what?
Technetium 99m (labeled to human albumin) perfusion
gas inhaled in V/Q during the inhalation phase
demonstrates what?
Radio labeled xenon gas
distribution of ventilation
when to to use V/Q scan
normal CXR with high probability of PE
test of choice for PE in pregnant women
V/Q scan
other usefulness of V/Q scan
estimating post-op reserve capacity for pts undergoing lung resection
contraindications of V/Q scan
NO ABSOLUTE CONTRAINDICATIONS
V/Q will def diagnose a PE if it’s there (v sensitive) but also might
be falsely positive bc it do that a lot
PET scan stands for
Positron Emission Tomography
what’s the benefit to a PET scan
Physiologic images that can detect biochemical changes of anatomy before CT/MRI
the radiation injected in PET scan
fluorodeoxyglucose (FDG)
this is radioactively labeled glucose
short-lived (benefit but time sensitive)
FDG accumulates in
tissues/organs with high metabolic activity
CANCER
measurements of radiation in PET scans
standardized uptake value (SUV)
what indicates cancer on PET scan
SUV >2.5
PET scan can evaluate
Metastasis from primary stie
effects of cancer therapy
recurrence in previously irradiated, scarred areas of the lung
When do false results occur with PET scans
metabolic imbalances
false (+) inflammatory lesions, granulomas (cocci and histoplasmosis)
false (-) slow growing tumors
indications for ultrasound (limited use) are
bedside detection of pleural fluid or pneumothorax
guidance for thracentesis and placing thoracostomy tubes
bronchoscopy can evaluate
pneumonia
hemoptysis
cough
bronchoscopy can diagnose
tracheoesophageal fistulas
tracheobronchomalacia
other things bronchoscopy can do
these are the things it’s most commonly used for
remove excess mucus or FBs (debris)
ET tube placement
trachea/proximal bronchus obstruction
side effects of bronchoscopy
nasal discomfort
sore throat
mild hemoptysis
complications of bronchoscopy
MINOR
hemorrhage
hypotension
arrhythmia
contraindications to bronchoscopy
severe refractory hypoxia
risk of bleeding
risk of respiratory and cardiovascular decompensation
what puts you at risk of respiratory and cardiovascular decompensation with bronchoscopy
asthma COP current/recent MI poorly controlled CHF life threatening arrhythmias
