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 Radiology Department’sInner Workings

                     

                                            

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

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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