CT Application 5 Trauma Flashcards
FAST
Focused Assessment with Sonography for Trauma
why CT is the undisputed gold standard
- immediate access
- high spatial res, specificity, sensitivity
- low scan time
FAST rapidly identifies free fluid in ___
abdomen / pericardium / pleural space
hemopericardium
blood in heart
hemoperitoneum
blood in peritoneal cavity
what is the initial assessment of trauma patients
FAST
advantages of FAST US
BANG
- beside imaging
- available
- no radiation
- guides insertion tubes & catheters
disadvantages of FAST US
LOL
- Limited visualization in big patients or GI gas accumulation
- Operator dependent
- Low reproducibility
advantages of x-ray
ABC
- available
- beside imaging
- cheap
disadvantages of x-ray
RPL
- radiation
- patient must hold still
- limited specificity & sensitivity
advantages of MRI
SHN
- SST visualization
- high sensitivity & specificity
- no radiation
disadvantages of MRI
- not easily available
- long duration
- costly
- contraindicated with metal implants
advantages of CT
EVC
- Evaluates multiple organs
- Visualizes pathologies beyond XR & US
- Contrast medium enhances evaluation
disadvantages of CT
- radiation
- allergic reactions
types of errors in trauma imaging
input, intention, execution
causes of errors made in trauma imaging
TIMU
- time critical decisions with concurrent tasks
- incomplete history
- mass causalities
- unstable patients
GCS
glasgow coma score
what is GCS used for
summary to determine impaired consciousness extent of patients but less detailed
what does GCS assess
- eye opening
- verbal response
- motor response
CT trauma preparation
triage > transfer > ct scan
what is the IV access for trauma patients
18G & 22G cannula
what is checked at triage phase of patient prep
- FAST Scan
- IV access
- creatinine & eGFR
c4 injury leads to
complete paralysis below neck
c6 injury leads to
partial paralysis of upper & lower limbs
t4 injury leads to
paralysis below chest
L1 injury leads to
paralysis below waist
what injuries lead to paraplegia
T4 & L1
what injuries lead to tetraplegia
C4 & c6
complete lesion defined as
no sensation / motor injury in lowest part of spinal cord S4/5 and no motor function at least 3 levels below spinal cord injury
incomplete lesion defined as
some sensation or voluntary movements below level of spinal cord injury
CT head indication
assess for traumatic brain injury
CT C-Spine indication
CXR AP & Lateral C-spine inconclusive
CT thorax & abdomen pelvis indication
patient hemodynamically stable & need to find active bleeding source
scan region for CT head
base of skull > vertex
scan region for CT cervical spine
craniocervical junction > T1
scan region for CT thorax abdomen
thorax and/or abdomen
algorithm for CT head
brain SST & skull
algorithm for CT cervical spine
bone
algorithm for CT thorax abdomen
SST, Lung, Bone
CTA
CT angiography
how does CTA work
CT + IV contrast to visualize blood vessels anatomy & flow to diagnose vascular diseases
purpose of CTA
- detailed visualization
- diagnosis
- pre & post operative use
- non-invasive alternative
aneurysms
outward bulge of blood vessel wall
stenosis
narrowed blood vessels = lower blood flow
occlusions
blood vessel blockage
embolisms
blood vessel blocked by blood clot
conventional diagnostic angiography is used for
interventional procedures unless tiny vessels to be studied due to invasiveness
magnetic resonance angiography provides excellent diagnostic quality for patients with ___
adverse reactions to CT contrast
disadvantage of magnetic resonance angiography is ___
poor resolution on vascular studies and subject image artifacts from metal / blood flow studies
which cannula used for CT angiography
18G
methods to optimize timing of CM injection to enhance images
fixed delay, bolus tracking, test bolus
fixed delay is __
predetermined delay between CM injection & start scan
bolus tracking is __
scanner continuously monitors ROI till desired enhancement reached from arrival of contrast bolus
test bolus is ___
small CM injection followed by series of low-dose scans to determine optimal timing for full contrast injection & scans
peak enhancement time of pulmonary artery
10 - 15s
peak enhancement time of arterial phase
25 - 40s
peak enhancement time of portavenous phase
80 - 90s
essentials for CTA
- large cannula access (18G/20G)
- thin slices to reformat MIP images
- high table speed
To ensure proper circulation timing, scanners use either ____ or ___
mini test bolus; automatic bolus tracking software
data acquisition of CTA
- scout / topogram
- arterial contrast IV injection
- CM timing
- data acquisition
- post processing
scan range of CT brain & carotid angiogram
aortic arch > vertex
pre-monitoring slice ROI of CT brain & carotid angiogram
aortic arch
scan range of CT aortogram
aortic arch > R & L iliac arteries
pre-monitoring slice ROI of CT aortogram
ascending aorta
aortic dissections
tear in internal face of aorta causes dissection through laminas & new lumen formation
what separates true & false lumina
dissection flaps
stanford type A aortic dissection
flap involves ascending aorta or great vessels
problems of stanford type A aortic dissection
urgent surgery due to occlusion risk & aortic valve regurgitation / rupture into pericardium
stanford type B aortic dissection
flap involves descending aorta
scan range of CT pulmonary angiogram
lung apex > lung base
ROI of CT pulmonary angiogram
pulmonary trunk
scan range of CT coronary arteries angiogram
carina > cardiac apex
ROI of CT coronary arteries angiogram
ascending aorta
pre monitoring slice of CT coronary arteries angiogram
mid chest near carina
problems with CT heart imaging
- max temporal resolution at 125ms
- ECG trigger/gating
- prospective trigger
- retrospective scans
prospective sequential ECG trigger
ECG signal used to trigger CT scan at selected heart phase which turns on & off during selected phases
retrospective ECG spiral
acquisition continuous as table moves forward with constant pitch but higher dose
prospective triggering
step & shoot which starts at preset in R-R internal period
pre-monitoring slice of CT angio lower limbs
upper abdomen
ROI of CT angio lower limbs
descending aorta below kidneys
___ slices used for MPR & MIP reconstruction
thin
dual energy techniques
- twin spiral
- twin beam
- dual source
energy spectra used for dual energy imaging
high (150 kV) & low (90 kV)
advantage of dual energy compared to conventional CT
materials with different elemental compositions can be differentiated and quantified by comparing their CT numbers at
two different energy levels
what is gout
monosodium urate crystals deposited commonly at 1st MTP joint
applications of image guided CT imaging
biopsies, drainage, radiofrequency, facet joint corticosteroid injection
commonly biopsied areas
bone, lungs, liver, kidneys, lymph nodes
purpose of CT nerve root block
pain management
why is CT nerve root block performed compared to spinal surgery
minimal invasiveness & lower risk
nerve root block involves injection of ___ anesthetic
steroid & local
complications of image guided CT
- pneumothorax
- bleeding
- hemoptysis
hemoptysis
airway bleeding