residents review course common radiology procedures an incomplete positioning guide george david,...
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Residents Review Course
Common Radiology ProceduresCommon Radiology Procedures
An Incomplete Positioning Guide
George David, MS, FAAPMLou Ann Burnett, BSRTDepartment of RadiologyMedical College of GeorgiaAugusta, Georgia
The Language of Diagnostic Radiology Bucky
LAO
All the KUB’s looked light
this morning?
The Language of Diagnostic Radiology
Phototiming
He’s gotta be taller
than that!Did we use a 40” SID?
40”?
Grids
The Language of Diagnostic Radiology
Barium EnemaDecub
Well, man, did you think
to checkfixer
retention?
Did they quit?
Common Practice:40” SID for Table Bucky
• Used for– table bucky– table top
• compromise between– intensity fall-off with
square of SID– geometric unsharpness Tablet op
“Patient”
SID
X
Cassette in Bucky
SID = source-image (receptor) distance
Common Practice:72” SID for Chest
• compromise between– intensity fall-off– geometric unsharpness– undesirable
magnification of heart
SID
X
Cassette in Chest Bucky
Patient
More Common Practice: Phototiming
• Exposure time controlled by generator– based on sampled radiation
• Used only for bucky exposures– not tabletop
• Positioning critical
Fixed TechniquekVp kVp
mA mAs
time
PhototimedkVp
density
sensor cell location
Bucky Imaging
• uses moving grid– reduces scatter– blurs grid lines– increases patient
exposure
• phototiming available
Tablet op
“Patient”
SID
X
Cassette in Bucky
GridPhototimerSensor
Non-Bucky Imaging• small body parts /
extremities– minimal scatter
• situation precludes bucky use– portables– cross-table lateral
• phototiming not availableTablet op
SID
X
Cassette
Body Part
Automatic Artifact
• Occurs whenever we image a 3D object in 2D
• Work-around– Multiple views
?? ??
Distortion TypesDistortion Types
X-RayTube
Image
Shape Distortion
X-RayTube
Image
Relative Position Distortion
minimal distortion when object near central beam & close to film
Common Projection Terminology
A = Anterior (front)P = Posterior (back)
AP
Oblique
PA
LAT
Common Projection Terminology• RAO
• LAO
• RPO
• LPO
Tablet op
LPO
R = RightL = LeftA = Anterior (front)P = Posterior (back)O = Oblique
Left Posterior of Patient Closest to Film
Can you identify
this man?
Decubitus Projection• Patient on side
• Causes changes in fluid levels
• Visualizes– plural effusion– air in abdomen
Cassette
Patient
Table
iliac crest
symphysis
coracoid process
orbitomeatal line
manubrial notch
Common Positioning Landmarks
patella
Chest Plain X-Ray
• High kVp– high latitude
required
• Phototimed• patient upright
– fluid levels / air
Technique
• PA
• LAT
Chest Plain X-Ray
• Minimizes heart magnification– 72” SID– PA view– LAT with left side toward receptor
Chest Plain X-Ray
•Shoulders rolled forward to remove scapulae shadows
•Include both lung apices and costophrenic angles
•Full inspiration
Chest Plain X-Ray
•Shows lung apices below clavicles
•Patient AP, leaning back
or tube angled 15-200 cephalic
Lordotic view
Chest Plain X-Ray
Pigg-O-Stat used for pediatric immobilization
Cassette
Chest CT
• Axial images• Patient supine • Feet first, arms raised• Scan from above lung apices
to below diaphragm• Routinely- 3 mm cuts• Contrast
– may be IV– highlights blood vessels
Technique
Chest CT
Scout image
Abdomen Imaging
• Plain X-Ray• Fluoroscopy
– Upper GI
– Lower GI (Barium enema)
• Abdominal CT• Nuclear Medicine• Ultrasound
Studies
Contrast Agents
• Water soluble (Hypaque)– better if leak
suspected
• Barium– highlights GI
tract
• Air
• Given orally
• Anatomy– esophagus– stomach– small
bowel
• Given by enema
• Anatomy– Colon
Upper GI Lower GI
Post fluoro views determined by radiologist
Abdomen Plain X-Ray
• Mid-range kVp
• 40” SID
• Phototimed
Technique
• AP (KUB)
• Upright or decubitus for air/fluid levels
KUB
• Patient supine • Center on iliac crest• Include diaphragm and symphysis
Decubitus Abdomen
•Side of interest up
•Center on iliac crest
•Include diaphragm
Abdominal CT• Routinely- 3mm cuts• Patient generally supine,
feet first• Scan from top of
diaphragm to iliac crest• IV Contrast highlights
– blood vessels– organs
• Dilute oral or rectal contrast highlights– GI tract– air not used
• streak artifact
Technique
Abdominal CT
Scout Image
Urinary Studies
Urinary Tract Studies
• Intravenous Pyelogram (IVPIVP)
• Retrograde pyelogram / cystogram– contrast delivered
through catheter• Voiding Cystogram• CT
– kidneys• Nuclear Medicine• Ultrasound
IVP• IV Contrast• Mid-Range
kVp– retain dye
contrast
• Images made at intervals post injection
• Post Void Image
Technique
• AP
• Obliques
• Center at iliac crest
• Include bladder and top of kidneys
Retrograde Studies
• Mid-Range kVp
• 40” SID
• AP
• Obliques
• Center on iliac crest for pyelogram
• Cystogram/urethrogram-include bladder and entire urethra
Kidney CT
• Patient positioned same as CT Abdomen
• Thin (1-2 mm) cuts• IV contrast used
if not post IVP
Technique
Circulatory Studies
• Arteriogram– carotid / aortic
arch– runoff (leg)– renal
• Venogram– much less
common– extremity
• Heart Catheterization
Angiography
Patient supine, centered over area of interest
Neuroradiology Studies• Skull Plain X-Rays• Spine Plain X-Rays• CT• MRI• Ultrasound• Myelogram
– Contrast injected into spinal canal– Mostly replaced by non-invasive MRI
Skull
• Mid-Range kVp
• 40” SID
Technique • PA– facial bones close to receptor
• reduces magnification
• LAT
• Many specialized views– Waters– Towne’s– Basal
Skull/SinusesPA
•Head rests on forehead and nose
•Orbitomeatal line (OML) perpendicular to receptor
•Angle tube 150 caudal
Towne’s
•Chin tucked, OML perpendicular to receptor
•Tube angled 400 caudal w/ patient AP
Skull/Sinuses
Water’s
•Routinely PA, chin up
• OML angled 300 to receptor
and nose ~1 cm from receptor
Skull/SinusesBasal •Routinely AP•If patient can tilt head back
–position tube / receptor lateral–OML parallel to image receptor
•If patient cannot tilt head back–tube / receptor tilted to achieve right angle to OML
•Shows zygomatic arches
Head CT
• 2 mm cuts• Orbitomeatal line
perpendicular to floor• IV Contrast highlights
– blood vessels– lesions (metastases)– aneurysms– AVM’s
Technique
MRI Brain Protocol
• 5 mm cuts, 1 mm spaces– minimizes crosstalk
• 1st study without contrast• If lesion suspected, study
repeated with contrast– Gadolinium injected IV– provides tumor edge
enhancement– aids in border determination
Spine
• Mid-Range kVp
• Usually 40” SID
• Phototimed
Technique• AP
• LAT
• Oblique
• Coned spot
• C-spine– flexion
• chin toward chest
– extension• head back
– open mouth odontoid
AP Cervical Spine•Occlusal plane and mastoid tips aligned-
to remove mandible shadow
•Angle tube 15-200 cephalic to open transverse foramina
•Center at thyroid cartilage
Lateral C-spine Imaging
Swimmer’s view for C7/T1
•Routine- 72” SID to reduce magnification
•Consider weight to lower shoulders
Odontoid Imaging
•Upper occlusal plane even with base of skull
•Mouth wide open
Thoracic Spine•Patient AP
•Upright or supine
•Center ~3-4” below manubrial notch
•Breathing technique to blur rib/lung markings
Lumbar SpineAP
•center on iliac crest Lateral •center on iliac crest• for spot, use 5-80 caudal tube angle to open L5/S1 space
AP Scoliosis Imaging
•Patient AP, standing
•Include thoracic and lumbar
•Use long cassette or “pieced” method
Myelograms•Fluoro with patient prone, knees and shoulders supported
•Cross-table lateral images at level of dye
•May CT while dye still present
Table
Skeletal• Extremity
– usually plain film
• Spine– plain film– CT– MRI
• Skull– plain film– CT– MRI
• Other– ribs– pelvis / hip
• Pain
• Trauma
Extremity
• Lower kVp• 40” SID• Not phototimed• No grid
Technique
• AP
• LAT
• Oblique
Hand/WristPA
Lateral- fingers spread
Center to 3rd metacarpophalangeal joint
ElbowAP
•Palm up to prevent forearm rotation
Lateral
•Elbow flexed 900
•Hand in lateral position
Center to joint
Shoulder Projections Axillary projection
•Arm abducted at right angle to body
•Shows glenoid/humerus joint
AP
•upright or supine
•Palm out to rotate shoulder to true AP
Center on coracoid process
Foot/Ankle
Weight-bearing lateral
•Demonstrate arch
•Center to base of 5th metatarsal
AP foot
•Sole flat on table
•Center to base of 3rd metatarsal
Knee Projections
Can be done AP…
•Angle x-ray tube 15-200 cephalic
…or PA
•Angle x-ray tube 15-200 caudal
Tunnel view of the intercondyloid fossa
Center on
patella
Knee Projections
Can be done PA…
•Angle 10-150 cephalic
Sunrise view of the patella
…or AP- standing, sitting
or lying
Center on
patella
Pelvis/Hips AP
• Patient supine
•Toes turned inward to show femoral neck
•Pelvis- Include top of crest and bottom of ischium
•Hip- center to joint
Pelvis/Hips
Frog Leg view
•Patient supine
•Knee(s) bent up and out
•Hip- center on joint
Cross-table Lateral HipSeen from side Seen from overhead
•Can’t frog leg/fractures
•Tube and receptor parallel
•Angle into joint
Mammography
•Compression to even out tissue densities
•Low range kVp
•Low dose film/screen combination
MammographyCraniocaudad (CC)
•Shoulder back, arm supported
•Nipple in profile
•Skin folds smoothed
MammographyMediolateral (ML)
Spot Compression•Unit angled•Arm supported•Nipple in profile•Skin folds smoothed