DA - Advanced Thoracic Testing - Exam 2

Chest CT Modality

-radiologic image that uses X-ray beams to create detailed images of internal structures

-images viewed in "slices"

Chest CT indications

-SX: persistent cough, difficulty breathing, SOB, chest wall trauma

-Conditions on ddx: pulmonary mass, PE, diffuse lung dz, smoking hx, ANL CXR, monitor tx, help plan for surgery/radiation

Chest CT CI

-renal insufficiency (contrast can worsen)

-pregnancy d/t radiation

-unstable pt (could code during scan)

-body habitus (depends on machine/table wt restriction)

Chest CT Procedure

-Pt lies on table and passes through XR tube

-computer processes XR beam to create 3D constructed image

-slices are axial, coronal, and sagittal views

Chest CT Advantages

-fast

-gives excellent detail in subtle differences in tissues

-images may be reconstructed in multiple planes or given 3D pictures

-not as expensive as MRI

Chest CT Disadvantages/Risks

-cannot be done portably

-large radiation dose/exposure

-contrast can cause renal injury

-more expensive than conventional XR

-performed at imaging center/hospital

Chest CT Comp

-AKI d/t renal failure --> contrast dye, must hold metformin for 48 hr after procedure

Chest CT Pt Prep

-remove metal objects

-contrast admin if indicated

Chest CT estimated cost

-medium - more expensive than XR, less expensive than MRI

-Exact cost depends on insurance, facility, etc

Chest CT w/ contrast

-contrast is IV, oral, or rectal can be used in scanning abdomen/pelvis

-IV contrast enhances the tissues to help distinguish abnormalities

-can be helpful with malignancy suspension

-provides more detailed imaging of structures

-Need contrast for PE, mediastinal widening, PE, malignancy, vascular abnormality

Without contrast

-limited usefulness

-use with pts w/ contraindications to contrast - allergy

-can use noncontrast for solitary pulmonary nodule

High Resolution CT

-thinner slides than standard CT

-sharper reconstruction = more fine detail

High Res CT Indications

-diffuse interstitial changes --> can distinguish between diff types of interstitial lung dz

-chronic dyspnea

-contrast not utilized

MRI modality

-non radiating image

-images viewed in slices

-better at soft tissue visualization

-utilized heavily in spine imaging

-pt must lay still the whole time

MRI Indications

-Sx: pain/neuro, bladder or bowel dysfunction

-DDX: degenerative spine dz, tumor eval (pancoast), thoracic outlet syndrome, cardiac indications (congenital heart dz, myocarditis, cardiac function eval, coronary heart dz)

MRI Contraindications

-Certain pt devices: pacemakers, defibrillators, insulin pumps/continuous glucose monitors, cochlear implants

-certain metallic objects (aneurysm clips, shrapnel esp in the eye)

-severe claustrophobia (may prescribe anxiolytic/benzo)

-renal insufficiency if using contrast

-unstable pt

-body habitus

MRI procedure

-pt lies on table and passes through imaging tube

-sound waves pulsed through a magnetic field to align protons in the body which creates the images

-slices are axial, coronal, and sagittal views

MRI Complications

-pt anxiety

-movement of metallic object in pts body

-disruption of pt device

MRI pt prep

-remove or turn off device if able

-ear protection

-contrast admin if indicated

MRI estimated cost

-higher cost --> more expensive than CT, actual cost dependent on insurance and facility

MRI vs CT

-MRI is non-radiating

-MRI takes longer (60 min vs 2-5 min)

-MRI is more expensive

-CT most often the first advanced imaging utilized except MRI better for spine and soft tissue eval

CT pulmonary angiography

-uses XR and contrast dye to visualize blood vessels

-Dx: PE (first line), pulmonary HTN, vascular ANL

MRA

-uses magnetic field and contrast dye to visualize blood vessels

-Dx: aneurysm, AV malformation, vascular abnormality

-NOT first line when making dx --> f/u imaging

PET Scan Modality

-nuclear medicine --> radiotracer admin IV, scan picks up gamma rays

-image created by showing areas of uptake

PET Scan Indications

cancer eval --> metastatic dz

PET scan CI

-allergy to tracer (very rare)

-pregnancy (relative)

PET scan procedure

-pt lies on table and passes through imaging tube

-axial, sagittal, and coronal views

Ventilation/perfusion (V/Q) scan

lung scan done to:

-find a blood clot that is preventing NL blood flow (perfusion) to part of a lung (PE)

-eval the flow of blood (perfusion) or air (vent) to the lungs

-see which parts of the lungs are working and which are damaged

-often done before lung surgery to remove parts of lung

Ventilation Scan

-a radioactive tracer gas or mist is inhaled into the lungs

-pictures from this scan can show areas of the lungs that are not receiving enough air or that retain too much air

-areas of the lungs that retain too much air show up as bright or "hot spots on the pics"

-areas that are not receiving enough air show up as "dark" or cold spots

Perfusion Scan

-a radioactive tracer substance is injected into a vein in the arm

-it travels through the bloodstream and into the lungs

-pics from this scan can show areas of the lungs that are not receiving enough blood

-tracer is absorbed evenly in areas of the lung where blood flow is NL

-areas that are not receiving enough blood flow show up as cold spots

matches

if lungs are working properly, blood flow on a perfusion scan _____________ air flow on a ventilation scan

PE

a mismatch between ventilation and perfusion scans may indicate what?

second line; second to CTA

are V/Q scans first or second line? why?

V/Q scans Indication

-allergy to CT contrast

-Renal Failure

1 hr

how long does a v/q scan take?

1 min

how long does a CTA take?

V/Q scan modality

-nuclear medicine

-image created by showing areas of uptake

-scan picks up where the tracer fills and where it doesn't --> indicating a filling defect = PE

V/Q Scan Indication

-pulmonary embolus, but not first line

-reserved for those w/ a severe contrast allergy

V/Q scan CI

-allergy to tracer (very rare)

-pregnancy

V/Q Scan Procedure

-2 scans done together: radiotracer admin by inhalation to show areas not getting air; tracer given IV to see what area is not getting BF

-if NL --> all areas match

-if ANL --> area of ventilation, perfusion mismatch

Conventional Pulmonary angiography

-modality: direct visualization of vasculature

-indications: PE, aneurysm, pulmonary HTN

-CI: bleeding/clotting risk, allergy to contrast, unstable pt

Conventional Pulm Angiography Procedure

-catheter placed in femoral artery, contrast dye injected, XR used to capture images of filling

-can also be therapeutic (removal of clot, embolization of aneurysm)

-very invasive --> all but replaced by CTPA except in cases where an intervention is being performed

CT chest w/ contrast

what imaging should you order for a pulmonary mass?

thoracic MRI

what imaging should you order for a pancoast tumor?

CT chest angiogram

what is first line imaging for a pulmonary embolism?

Pulmonary Embolism 2nd line imaging

-CT chest if CTPA not available

-V/Q scan if allergy severe

-Not first line but conventional pulmonary angiogram if you can remove clot

High res CT

what imaging should you order for diffuse lung disease?

thoracic (spine) MRI

what imaging should you order for thoracic bony disease?

PET Scan

what imaging should you order for metastatic disease?

Pulse Oximeter

-measures arterial oxygen sat

-changes in light absorption of oxygenation and deoxygenation hemoglobin

-ratio of this estimates the measurement

-given as a percentage

Pulse Ox indication

-5th vital sign

-any resp complaint --> cough, dyspnea

-monitoring response to breathing tx

Pulse Ox Pt Prep

-probe applied to fingertip - remove fingernail polish if necessary

-alternative probes can be attached to webbing of hand, foot, or earlobe

-different probe options for peds pt

arterial oxygen sat

what does pulse ox correlate with?

Arterial oxygen saturation

-true arterial oxygen levels w/in 2-3% when SpO2 is >90%

-SpO2 is sig less reliable when <90%

Sputum Culture

-potential growth and ID of bacteria within sputum sample

-Indication: TB (6 wk growth period), pneumonia

Sputum Culture Pt Prep

-sample should be collected in early morning, before:

-eating, drinking, brushing teeth, using mouthwash, smoking

-may collect sample via bronchoscopy

no

is sputum culture always accurate?

no

is sputum culture good for lung abscesses?

Bronchoscopy

-endoscopic procedure to visualize interior of airways and sample collection --> samples sent for culture or cytologic analysis

Bronchoscopy Sample Collection

-lavage (cytologic and microbiologic sampling) --> collects pathology at alveolar level

-washing (similar to lavage but uses less saline)

-Brushing (cytologic sampling) --> endobrachial lesions

-biopsy

-aspiration

Bronchoscopy Pt Prep

-NPO to reduce risk of aspiration

-Pt is sedated

-endotracheal tube passed into trachea --> enters through nose or mouth, vent provided through the ETT tube

Bronchoscopy CI

-unable pt condition

PPD Tb Testing

-TB skin test --> can be screening for employment, incarceration, exposure; or dx if symptomatic

-Intradermal injection of purified protein derivative (PPD) antigen proteins

Two Step PPD/TB Skin Test

-one TB skin test followed by a second TB skin test 1-2 weeks later

-sometimes required at places of employment

TB testing CI

-Hx of BCG vaxx

-active TB infxn

-previous severe reaction to TB skin test

low cost

what is the cost of TB skin testing?

T-spot Test

-blood test, enzyme linked immunospot assay

-TB antigens are admin and then let it incubate x 48-72 hr

-blood sample taken and analyzed for rxn w/ TB antigens --> test looks for number of cells that react

-produces a positive, negative, and indeterminate result

-fewer false +

-screening for employment or dx for symptoms

T-spot Costs

-higher than PPD

no

is the T-spot TB test affected by a prior BCG vaxx?

Quantiferon Gold

-blood test, enzyme linked immunosorbent assay (ELISA) --> blood sample is collected and analyzed for presence of interferon gamma proteins

-produces a +, -, and indeterminate result

-fewer false positives

-more automated than a T-spot

-screening or dx of symptomatic

-cost: higher than PPD

-more specific and less false positives than a PPD

no

is the quantiferon gold test affected by the BCG vaxx?

Sweat Test

-measures the chloride and sodium levels in a sweat sample

-gold standard dx for CF

Sweat Test Procedure

-localized area stimulated to sweat by application of pilocarpine and electrodes x 5-12 min; babies b/l collection areas, usually wrists

-clear area then apply a filter paper or collection device x 60 min

-most collect at least 100 ug

-sample analyzed for Cl and Na contents

Sweat Test Neg/NL

-cleared of disease

-<29 mmol/L

Sweat Test intermediate

-30-59 mmol/L

-unsure of dx: need to correlate w/ other testing

-repeat sweat tests, stool enzyme tests, further genetic testing

Positive Sweat Tests

->60 mmol/L

-Dx for CF

-need for additional testing: stool enzyme tests, further genetic testing