Medical Diagnostics Exam 1 Flashcards
Radiation measurements
R = roentgen Rad = Radiation absorbed dose Rem = Rad equivalent man
For diagnostic radiology purposes
R=Rad=Rem
all the same
colles
distal radial fx
foosh
elderly women
kids
Odontoid fx
C2 fx
3 types
Top of dens
bottom of dens
through mian part of bone
Ultrasound pearls
Pregnancy intraabdominal pediatric cheap fast harmless results vary based on skill of tech limited scope worse for high BMI patients
Lunate dislocation
FOOSH
palm strike
Spondylosis
SPONDLYLOSIS is a bony defect of the pars interarticularis
It happens most often in adolescent athletes and at the L5 vertebrae.
The defect results in formation of a “collar” around the Scotty Dog Model of the lumbar vertebrae
Osteosarcoma
• Most common primary malignant bone tumor
70% show evidence of pulmonary metastasis, death usually secondary to respiratory compromise
can be familial
sunburst or codmans triangle
Which of the following findings will prevent you from administering IV contrast
- Creatinine 1.8
- O2 saturation of 93%
- Chronic use of Metformin
- Flushing upon prior administration of contrast
- Creatinine 1.8
Transverse Avulsion Patellar Fracture
Caused by indirect force generated by the quadriceps tendon.
radial head fx
FOOSH
most common elbow fx in adults
hard to see on xray
look for sail sign or fat pad
Does the “air” appear differently on CT or Xray in terms of contrast
No, air looks black and the same in both CT and x ray
Triquetral Fracture
2nd most common after scaphoid
Computed tomography CT
is x rays constructed by a computer
Bennett Fracture
broken / dislocated thumb
twisting hand around a tubular body
shoulder dislocation
anterior most common
head down and forward
posterior
Very uncommon and can be easily missed
what does the collimator do
Narrows the rays and focuses the x rays
soft tissue imaging
MRI
to image soft tissue
low kVp
low mAs
Adverse reactions
Idiosyncratic vs non idosyncratic
Lisfranc Injury
A fracture and or dislocation at the tarsometatarsal joint.
Seen in mountain bikers who get their feet caught in the pedal clips
gold standard of imaging of arterial system
angiography (arteriography)
Immobilize yes or no?
All suspected and confirmed
fractures need to be
immobilized.
Degenerative Joint Disease
Note Osteophyte Formation
• Decreased Joint Space
• Sclerosis
irregular joint spaces
Oral contrast and weight
Oral contrast is recommended for people with BMI less than 21 due to lack of fat
MRI pearls
Expensive
no radiation
good for pregnant
excellent for soft tissues
Ultrasound colors
Solid structures appear white
Cystic structures appear black
Doppler to detect flow
Red towards transducer
blue away from transducer
Echogenicity
SCFE
Slipped capital femoral epiphysis
ball head of femur slipps of the neck (broken)
emergency
happens in kids
Tear drop fx
diving into pool
tear drop piece breaks off spine
Segond Fracture
anterior cruciate ligament tears are
commonly associated with this type
of fracture
CT artifacts
Movement
Dust particles
foreign bodies
Which cervical injury mandates neurosurgery consultation in
absence of any neurovascular compromise?
- Clay Shovelers Fracture
- Wedge Fracture
- Odontoid Fracture
- Compression Fracture
- Odontoid Fracture
due to being unstable fx
tomography
Same as x ray except the x ray tube and the film move at the same time
Scoliosis image
must have whole spine in film to see diffenret angle of rotation
MRI signal strength image
Strong image will appear white (high intensity)
fluid
Weak signal wil appear gray (low intensity)
Soft Tissue
No signal will appear black
Air, bone (very dense)
how is radiation absorbed
it differs depending on the type of tissue
Bone and tissue absorb differently
Measured in sieverts
CEUS
Contrast Enhanced Ultrasound
Microbubble contrast agents smaller than RBC’s
Enhance doppler imaging
Pelvic sacrum trauma
severe pelvic truama is associated with hemorrhage 60% of the time
it is the main cause of death in this population
metformin and contrast
must stop metformin until 2 days after contrast due to the high rate of lactic acidosis
What is the ideal combination of kilovoltage and milliamperes per second when evaluating soft tissues on an xray?
- High kVP, High mAs
- Low kVp, High mAs
- High kVp, Low mAs
- Low kVp, Low mAs
- Low kVp, Low mAs
Adverse reactions
MIld - moderate - severe
Mild - N/V , flushing
moderate - uticaria, bronchospasm, vasovagal
Severe (rare) - seizures, Altered mental state, Cardiac arrest
Unilateral Facet dislocation
Facet joint dislocation and rupture of the apophyseal joint ligaments resulting from rotatory injury of the cervical vertebrae: simultaneous flexion and rotation.
Could be confused with spondylolisthesis
(spondylolisthesis usually occurs in lower back, not c spine)
Imaging costs
CT 51 & 1565
xray and US 55 & 410
Nuc med 135 & 1138
MRI 165 & 2048
Malignant Bone Tumor
Primary, Metastatic Moth eaten
or permeative appearance to
margins
Malgaigne Fracture
Articular or para-articular
fracture of the sacroiliac joint
and ipsilateral ischiopubic rami.
Multiple myeloma
Males, AA, over 45
common to kidney disease
punched out lesions (russel bodies)
Burst fx
crushed vertebral body
compression fx
Luxatio Erecta Shoulder Dislocation
Arm dislocated straight up
Radiopaque vs radiolucent
Radiopaque is radio dense / structures appear white
Radiolucent / structures appear black
Adverse reactions
Non - Idiosyncratic
occur rapidly can have metallic taste warth / flushing urge to urinate bradycardia, hypotension, vasovagal
can lead to vascular collapse / death
Nuclear medicine agents
Technetium 99m (bone)
Gallium 67 Inflammatory disorders (tumors)
Indium 111 WBC (acute infections)
Labeled WBC
Benign Bone Tumor
- Well demarcated (round/oval)
* Narrow zone of transition
A 5yo female is in your office for evaluation of fall and elbow injury. Lateral elbow xray reveals posterior fat pad or Sail signs, which is an indication of what condition?
- Dislocation
- Hemarthrosis
- Sprain
- Contusion
- Hemarthrosis
Gout
red hot swollen joint
podagra
rat bite erosions
Imaging
Film is fragile, flammable, wrinkles and gets moldy
Most imaging today is digital
Osteomyelitis in Diabetics
• 94% of cases of diabetic osteomyelitis in the foot are
associated with ulcers. So if an ulcer is absent, osteomyelitis is
unlikely
Charcot (Neuropathic Joint)
MRI gold standard (acute)
Dexa Scan
Dual Energy Xray Absorptiometry
Used for osteoporosis diagnosis
Used to determine bone mineral density (BMD)
Arthrography
Imaging of a joint with contrast
can be injected with iodine contrast or air
Scottie dog sign
normal appearance on lumbar imaging
radiation proteciton
gold is best protector
lead is used due to cost
When is the swimmers view useful
heavy people
Calcaneal Fracture
lovers fx
fall from height
GRUM
Galleazi = Radius Ulna = monteggia
C spine soft tissue measurements
Area Adult Child
Predental space < 3mm < 5mm
Retropharyngeal space < 7mm < 7mm
(anterior to C3)
Retrotracheal space < 22mm < 14mm
(anterior to C6)
Adverse reactions
Idiosyncratic
Happen for no reason unpredictable usually within 20 minutes can occur with as little as 1 ml prior sensitivity testin of no value
can go from mild to severe
patella fx
sunrise view
MRI T1
T1 images
White Matter appears white, gray matter appears gray, CSF is black
Best for normal anatomy
Fat and bone marrow appear bright
Tendons, ligaments, cortical bone, and air always appear black
because of their lack of water content
Femoral neck fx
in osteoporosis patients
the bone breaks then they fall
associated with meonpuase
avascular necrosis occurs about 10-30% of the time
John thomas sign
How long should you avoid iodine contrast before Iodine 131 is given for thyroid ablation
2 months
scaphoid fx
most common fx carpal
FOOSH, extreme dorsalflexion
avascular necrosis can occur
Arterial duplex
Arterial occlusive disease
BERT
Background equivalent radiation time
This increases with altitude
a single transcontinental roundtrip flight is equal to 2.5 chest xrays
Measured in sieverts
Shaken baby
Skull and C1 seperation
Color doppler US
for flow and turbulence
Metastatic Bone Tumors
Metastatic bone tumors are much more prevalent than
primary bone tumors
most common originate from five organs:
breast, kidney, lung, prostate, and thyroid.
Generally, if there are “hot spots” in asymmetric areas in such
patients, the radiologist assumes they represent metastases
Maisonneuve Fracture
Fracture of the proximal half of
the fibula.
strong eversion at
the ankle joint.
Is flexion C-Spine xray appropriate if you suspect teardrop fracture?
NO
never flexion or extention in c spine fx
Tillaux Fracture
Lateral margin avulsion of the
distal tibia.
You are evluating a patient following MVC with suspected ligament injury. What imaging modality will best evalutate this pathology?
- Xray
- CT
- Ultrasound
- MRI
- MRI (proton density) (flair)
CT is good, but MRI is better
Nuclear medicine
uses radioactive substance
expressed as high or low intensity
hot or cold
hot appears black
cold appears white
Rheumatoid arthritis
MRI early, xray late in disease
Hangmans fx
C2
hitting windshield
pars interarticularis fx
US Artifacts
Mirror image Acoustic shadow Acoustic enhancement Reverberation Refraction
lower extremity
soft tissue injuries are most
then FX
then dislocations
Greenstick 3 types
transverse (fx halfway across bone)
torus (buckling, overlap)
bowing (bent without crack)
common in abuse
In suspected perforation what contrast should you give
Gastrografin
It is water soluble and can be diluted
Doesn’t coat mucosa as well as barium
pretreatments for allergic reactions
prednisone 50mg
benadryl 50mg
Contrast ordering
Bony abnormalities, pneumonia = none
Soft tissue trauma = IV contrast
Cellulitis, infection, inflammation = IV contrast
PE, aortic dissection, renal stones= with or without
bowel abnormalities = with oral contrast
What is a normal predental space in an adult c-spine evaluation?
- < 3 mm
- < 5 mm
- < 7 mm
- < 14 mm
- < 3 mm
Creatinine level to receive IV contrast
creatinine 1.4 to 1.7
depends where you work
higher wont get IV Contrast
Salter-Harris IV
Second most common SH Fx
• Extends through epiphysis,
physis, and metaphysis
• Can result in disability
• Usually will require surgical
repair
scapula fx
force to break scaupla warrants a CT
Thurston-Holland Sign
A triangular
metaphyseal fragment seen in
Salter-Harris type II fractures
Radiation monitoring
Thermoluminescent dosimeter
= 3 months, more expensive
not as common
Film Badges
= 1 month
less expensive
more common
MRI imaging weighting
T1 short TR, Short TE
T2 Long TR, Long TE
2 is greater than 1
How to protect from ionizing radiation
reduce time
increase distance
shielding
Collimate (focus the beam)
Increasing the distance is the most effective way to limit radiation exposure
Ewing Sarcoma
Primary malignant bone tumor
– Highly metastatic
Most common malignant bone tumor seen in children
onion skin, hair on end
3 images angles for C spine
Lateral,
AP,
odontive
Flouroscopy
Mobile xray
generates realtime continuos results
adjustable x ray beam
visualization of anatomical structures in real time
Gadolinium
Gadolinium Deposit Disease
2017
neurovascular complications
neuropathic pain
Nephrogenic system fibrosis
Renal impairment
2-10 weeks
Posterior hip dislocation
trauma
90% are posterior
sciatic nerve issues in 10%
MRI T2
T2 images
CSF is white, Fatty structures are darker
Best for pathology, Water, edema, acute hemorrhage appear bright
Tendons, ligaments, cortical bone, and air always appear black
because of their lack of water content
Spondylolithesis
Anterior slipping is termed SPONDYLOLISTHESIS.
Osetomyelitis
Bone erosion and destruction
DDX
iv drugs, neck/back pain
Ethical principles of radiology
Autonomy
Beneficience
Nonmaleficence
Justice
Pagets disease
abnormal calcium depostis on bones
Ottawa Ankle Rules
Presence of point tenderness at either of the 4 spots and inability to bear weight following injury warrants xray imaging.
- medial malleolus
- lateral malleolus
- Navicular Bone
- Bas eof 5th metatarsal
ALARA concept
As Low As Reasonable Acheivable
Radiation limit set by a council
Radiation worker = 5 REMS per year
Average population = 0.5 Rems per year
CT on a pregnant woman
Do not image in first trimester abdomen pelvis lumbar spine hips
unless mother is going to die
otherwise choose alternate (MRI, US)
Two most important US artifacts
Echo of posterior enhancement
Bright band extending from posterior to the weak attenuator
Distinguishes cyst from lesion
y
Shadowing
Decreased posterior attenuation of highly reflective surfaces
Helpful in stones identification
Acromio-Clavicular Joint Separation
3 types
Type 1 - Partial tear
Type 2 - Disruption of the acromioclavicular ligament
Type 3 - Disruption of the acromioclavicular and coracoclavicular ligaments
Wedge Fracture
Compression fracture resulting from flexion.
Very common in ED setting
2 tyeps of biological effects of radiation
Genetic effect
DNA molecules are damaged
can pass on to offspring
Somatic efect
cellular effects
burns, hairloss, cancer etc
not passed on
Venous Duplex
DVT venous valvular incompetence
Clay Shoveler’s Fracture
Fracture of a spinous process C6-T1
MRI how it works
Radio waves excite hydrogen atoms in a patients fat and water molecules
they align themselves with magnetic fields
computer analyzes and reconstructs it
Absorbtion does not matter (radiopaque, radiolucent dont apply)
supracondylar fx
median nerve
most common in peds
fx above epicondyle
Nuclear medicine scans contrasts
Tc99m MDP (Methyl Diphosphonate) Cancer/infection
• Tc99m HMPAO-WBC (Ceretec)
infection
• Indium 111 WBC
all are used for Osteomyelitis in Diabetics and charcot
What are L1 fx linked to
Calcaneal fx
Who discovered x rays
Wilhem Rontgen
1895
How much radiation is in 1 abdominal CT
1 REM
= to 500 chest xrays
or 4.5 years of background radiation
Salter-Harris V
Epiphyseal plate injury only
• Have poor prognosis and
significantly alter further growth
refer to specialist
MRI safe devices
Fillings, Braces, IUD’s
Surgical hemostasis clips (2-3months post implant)
CT benefits
Excellent contrast resolution
Cross sectional images in mostly axial plane
excellent for imaging cortical bone
Jones fx
Fracture of the base of the fifth
metatarsal, at least 1.5 cm. distal
to the metatarsal styloid.
avascular necrosis
prompt orthopedic follow-up.
Osteoid Osteoma
Distinctive benign osteoblastic tumor • Painful • Pain increased at night • Classically relieved with aspirin (NSAID) • Pinpoint tenderness directly over lesion
Tibial Plateau Fracture
Occur most often are the result
of a moving vehicle striking the
knee.
Preferred imaging for C spine
CT
up to 20% of fx missed on xray
(in the field) = crosstable c spine xray
(in ed) = CT w/o contrast
Duplex ultrasound
Clear Fluid appears black
(anechoic {no echo])
Not clear fluid will apear gray
Salter harris III
Physis and epiphysis fractures
• Usually requires surgical
intervention
Site for Bone mineral density
using dexascan
hip and spine to diagnose osteoporosis
forearm also for alternative
uses statistical analysis
Radiology team
Radiologist Diagnostic medical physicist Radiology Assistant Radiology Nurse Radiology Tech
Bilateral facet dislocation
complete anterior dislocation of the vertebral body resulting from extreme hyperflexion injury
Amount of radiation required to die in short period of time
400 REM
1 REM = 500 chest xrays
When should you avoid barium sulfate
when perforation or peritonitis is suspected
Barium sulfate not water soluble
Radiation in pregnancy
embyologic effects
effects on th embyro
first six weeks (first trimester)
most radiosensitve
most severe effects occur during this time
sensitiviy decreases in 2nd and 3rd trimester
Galeazzi Fracture
proximal radius fx with distal radial dislocation
Rolando fx
Comminuted (or 3 part) intraarticular fracturedislocation of the base of the thumb (proximal first metacarpal).
Essentially a comminuted Bennett Fracture
DM with Charcots foot. Not sure
about osteomyelitis based on
plain xray results.
What imaging study would you
order?
WBC scan
MRI Contrast
Most are gadolinium enhanced to produce “positive” or
enhanced contrast mostly on T1 weighted images.
• T2 effects are negligible
• Types of contrast material
– Extracellular agents
– Blood Pool agents
– Hepatobiliary agents
Scottie dog sign with collar
SPONDLYLOSIS is a bony defect of the pars interarticularis
looks like collar
kVp
Kilovoltage (for xrays)
Affects the quality or penetrating power of the beam
differnet kVp depending on what you are trying to image.
A68yo AAF presents to your ED for evaluation of fall. On exam
you note right leg shortening and rotation. What is the most
likely pathology expected on imaging?
- Comminuted Nondisplaced Femoral Fracture
- Hip Dislocation
- Patellar Fracture
- Hip Fracture
- Hip Fracture
Monteggia Fracture
Fracture of the ulna with
accompanying radial head
dislocation.
Cells and radiosensitivity
Reproductive and WBC are most radiosensitive
Muscle, nerve, bone have low sensitivity
psisform fx
rare
crush injury
best view for assessing soft tissue
Lateral view
Heterotopic Ossificans
extra bone growth
can be caused by trauma or surgery
hip joint replacemtn
Jefferson fx
C1 fx
crush
broken in places
Contrast
ateriograms, venograms, ingested contrast
Iodine and barium
IV contrast is always iodine
Proximal Tibial Stress Fracture
Nuclear bone scanning is more
sensitive for this diagnosis.
helsp diffeentiate between osgood schlatter
