radiograph artifacts

RadiogRaph RadiogRaph aRtifactsaRtifacts

Dr. Simran SinghResident,

JSSMC,Mysore.

definition definition

Artifact is defined as any opacity on the Artifact is defined as any opacity on the radiograph which does not correspond to radiograph which does not correspond to an actual anatomic structure.an actual anatomic structure.

Any misinterpretation of an actual Any misinterpretation of an actual anatomic structure.anatomic structure.

Anything decreasing radiographic quality.Anything decreasing radiographic quality.

classification of aRtifactsclassification of aRtifacts

BRoadeR classificationBRoadeR classification

step specific classification step specific classification

Storage and pre-exposure handling artifacts.Storage and pre-exposure handling artifacts.

Positioning artifacts.Positioning artifacts.

Exposure artifacts.Exposure artifacts.

Post exposure artifacts.Post exposure artifacts.

Processing artifacts.Processing artifacts.

Work station artifacts (applicable for CR/DR).Work station artifacts (applicable for CR/DR).

stoRage and pRe-stoRage and pRe-exposuRe aRtifactsexposuRe aRtifacts

Screen fi lmScreen fi lm

oPressure Pressure oAbrasions and scratchesAbrasions and scratchesoFingerprintsFingerprintsoStatic electricityStatic electricityoMaterial in cassette Material in cassette oFogFogoLight leakLight leak

CR/DRCR/DR

oStorage scatterStorage scatter

pRessuRe aRtifacts –pRessuRe aRtifacts –film cRease cRescents film cRease cRescents

Black & focal.Black & focal.

Cause: rough handling.Cause: rough handling.

Pressure from crease Pressure from crease causes activation of causes activation of crystals.crystals.

NOT caused by NOT caused by fingernail (usually).fingernail (usually).

aBRasions & scRatchesaBRasions & scRatches

Black or white, focal.Black or white, focal.

Cause: rough handling.Cause: rough handling.

Black: pressure from abrasion Black: pressure from abrasion activates crystals.activates crystals.

White: emulsion has been White: emulsion has been removed (scratch).removed (scratch).

Can feel texture in emulsion.Can feel texture in emulsion.

fingeRpRintsfingeRpRints

Focal.Focal.

White: most common.White: most common.

Oil on fingertips Oil on fingertips blocks developer.blocks developer.

OROR

Fixer on fingertips.Fixer on fingertips.

Finger prints..Finger prints.. Black: less common.Black: less common.

Developer on Developer on fingertips.fingertips.

Prevent:– Keep Prevent:– Keep fingers dry and clean fingers dry and clean Touch only film Touch only film edges.edges.

static electRicitystatic electRicity

Black & focal.Black & focal.

Two patternsTwo patterns - Branching- Branching - Smudge / Spot- Smudge / Spot

Cause: electrical Cause: electrical discharge.discharge.

To prevent:To prevent:

– – Moderate humidity.Moderate humidity.

– – Avoid friction while Avoid friction while handling film.handling film.

– – Antistatic cassette Antistatic cassette cleaners.cleaners.

static electRicitystatic electRicity

mateRial in cassette /mateRial in cassette /diRty scReendiRty scReen

White & focal.White & focal.

Sharp margins (close to Sharp margins (close to film – no penumbra).film – no penumbra).

Cause: Visible light Cause: Visible light photons from screen photons from screen can’t reach and expose can’t reach and expose film emulsion.film emulsion.

Thus “radiolucent” Thus “radiolucent” material can still material can still cause this artifact.cause this artifact.

Common causesCommon causes––HairHair––DustDust

FogFog

Increased blackness, usually Increased blackness, usually regional or global.regional or global.

Definition: any unwanted film Definition: any unwanted film exposure / development.exposure / development.

Decreased image contrast Decreased image contrast and detail.and detail.

Causes for FogCauses for Fog Light exposure.Light exposure.

Heat (store at < 68 F).Heat (store at < 68 F).

Humidity (keep at 30-50%).Humidity (keep at 30-50%).

Radiation (including scatter).Radiation (including scatter).

Chemicals.Chemicals.

Old film.Old film.

Light LeakLight Leak

Black, focal to global.Black, focal to global.

A form of fog.A form of fog.

Sources:Sources:– – Storage bin (along 1 edge)Storage bin (along 1 edge)– – Cassette not closed.Cassette not closed.(1 edge or corner)(1 edge or corner)– – Overhead light.Overhead light.– – Safelight filter crack.Safelight filter crack.

Positioning artiFactsPositioning artiFacts

Screen-FilmScreen-Film

MagnificationMagnification

Foreshortening /distortionForeshortening /distortion

Patient rotationPatient rotation

Upside-down cassetteUpside-down cassette

Grid cutoffGrid cutoff

CR & DRCR & DR

MagnificationMagnification

Foreshortening /distortionForeshortening /distortion

Patient rotationPatient rotation

Upside-down cassette Upside-down cassette (CR) or panel (DR)(CR) or panel (DR)

Grid cutoffGrid cutoff

MagniFicationMagniFication

Object closer to film:Object closer to film:

Closer to normal sizeCloser to normal size Sharper marginsSharper margins

Object farther from film:Object farther from film:

MagnifiedMagnifiedLess distinct marginsLess distinct margins

Foreshortening / Foreshortening / DistortionDistortion

X-ray beam does not pass X-ray beam does not pass perpendicular to long axis perpendicular to long axis of structure.of structure.

Differential magnification Differential magnification of structure.of structure.

Patient rotationPatient rotation

A form of distortion.A form of distortion.

Lesions may be masked Lesions may be masked by atypical by atypical superimposition on superimposition on normal anatomy.normal anatomy.

Unusual projection of Unusual projection of normal anatomy may be normal anatomy may be incorrectly diagnosed as incorrectly diagnosed as abnormal.abnormal.

UPsiDe-Down cassetteUPsiDe-Down cassette

White & focal.White & focal. Springs & latches on back of Springs & latches on back of

cassette block x-ray beam.cassette block x-ray beam.

Global lightness.Global lightness. Lead backing absorbs some Lead backing absorbs some

x-ray photons (film appears x-ray photons (film appears underexposed).underexposed).

UPsiDe-Down cassette UPsiDe-Down cassette artiFactsartiFacts

Image patterns from the plastic support structures in the CR cassette are superimposed on the anatomy, caused by the placement of the imaging plate and the cassette upside down in the cassette holder.

UPsiDe-Down PaneL (Dr)UPsiDe-Down PaneL (Dr)

White & multifocal.White & multifocal.

Electronics in the back of Electronics in the back of the panel absorb x-rays.the panel absorb x-rays.

griD cUt-oFF griD cUt-oFF

White, regional to global.White, regional to global.

Orientation of lead strips in Orientation of lead strips in grid requires appropriate grid requires appropriate geometry relative to x-ray geometry relative to x-ray beam.beam.

Wrong geometry lead strips Wrong geometry lead strips attenuate more x-rays.attenuate more x-rays.

LateraLLy DecentereDLateraLLy DecentereDFocUseD griDFocUseD griD

Result: Too white acrossentire image

oFF-LeveL FocUseD griDoFF-LeveL FocUseD griD

Result: Too white acrossentire image

Upside-down FocUsed GridUpside-down FocUsed Grid

Result: OK in the center,Severely too white at periphery.

distance decentereddistance decenteredFocUsed GridFocUsed Grid

Similar to upside down gridSimilar to upside down grid – – OK in the center, OK in the center,

Markedly too white at Markedly too white at periphery.periphery.

Often not as severe as Often not as severe as upside-down grid.upside-down grid.

Exposure ArtifactsExposure Artifacts

Screen-FilmScreen-Film

MotionMotionDouble exposureDouble exposureOverexposureOverexposureUnderexposureUnderexposureMaterial obstructing x-Material obstructing x-ray beamray beam

CR & DRCR & DR

MotionMotionDouble exposureDouble exposureOverexposureOverexposureUnderexposureUnderexposureMaterial obstructing x-Material obstructing x-ray beamray beam

Motion Motion

Blurring of moving parts.Blurring of moving parts.

Exposure does have a finite Exposure does have a finite interval.interval.

Reduce with:Reduce with:– – Better restraintBetter restraint– – SedationSedation– – Decreased exposure timeDecreased exposure time

doUble exposUredoUble exposUre

Appearance of 2 summated imagesAppearance of 2 summated images

Cause: Cassette inadvertently exposed more Cause: Cassette inadvertently exposed more than oncethan once* * Press exposure trigger twicePress exposure trigger twice* Forget to change cassette after first view* Forget to change cassette after first view

SF: Black, global. SF: Black, global. – – 2 exposures =overexposure artifact2 exposures =overexposure artifact

CR: Normal grayscale as the wide latitude CR: Normal grayscale as the wide latitude can usually accommodate the overexposure. can usually accommodate the overexposure.

DR: Can’t happen as image is transferred to DR: Can’t happen as image is transferred to computer immediatelycomputer immediately

overexposUreoverexposUre

Black & global.Black & global.

Patient info label normal.Patient info label normal.

Cause: Too much activation Cause: Too much activation of emulsion crystalsof emulsion crystals– – High mAs or kVpHigh mAs or kVp––Line surgeLine surge– – Double exposure, FogDouble exposure, Fog

UnderexposUreUnderexposUre

White & global.White & global.

Patient info label normal.Patient info label normal.

Cause: Too little activation of Cause: Too little activation of emulsion crystalsemulsion crystals– – Low mAs or kVpLow mAs or kVp– – General x-ray obstructionGeneral x-ray obstruction– – X-ray tube troublesX-ray tube troubles

UnderexposUre:UnderexposUre:QUantUM Mottle (cr, dr)QUantUM Mottle (cr, dr)

Noisy & global.Noisy & global.

Computer algorithms Computer algorithms adjust image to remain adjust image to remain gray.gray.

Low signal level causes Low signal level causes grainy appearance and grainy appearance and poor contrast & poor contrast & sharpness.sharpness.

Cause: As with SF.Cause: As with SF.

Under and over…Under and over…

Underexposed

Normal Overexposed

Material obstrUctinGMaterial obstrUctinGx-ray beaMx-ray beaM

White, focalWhite, focal

Cause: Any Cause: Any radiopaque structure radiopaque structure in the path of the xray in the path of the xray beambeam– – On patientOn patient– – In patientIn patient– – On tableOn table– – On cassetteOn cassette

post-exposUre post-exposUre HandlinG artiFactsHandlinG artiFacts

Screen-FilmScreen-Film

PressurePressureAbrasionsAbrasionsFingerprintsFingerprintsStatic electricityStatic electricityFogFog Light leakLight leak

CR & DRCR & DR

Not ApplicableNot Applicable

processinG / readinG processinG / readinG artiFactsartiFacts

Screen-FilmScreen-Film

OverdevelopmentOverdevelopmentUnderdevelopmentUnderdevelopmentIncomplete fixationIncomplete fixationIncomplete washingIncomplete washingKissing defectsKissing defects

CR & DRCR & DR

Dirty light guide (CR)Dirty light guide (CR)Cassette debris (CR)Cassette debris (CR)

overdevelopMentoverdevelopMent

Black & global.Black & global.

Patient info label also Patient info label also black.black.

Cause: Too much Cause: Too much metallic Ag forms in metallic Ag forms in emulsion crystalsemulsion crystals

– – Developer too hotDeveloper too hot – – Developed too longDeveloped too long

UnderdevelopmentUnderdevelopment White & global.White & global.

Patient info label also Patient info label also white.white.

Cause: Too little Cause: Too little metallic Ag forms in metallic Ag forms in emulsion crystalsemulsion crystals

––Developer too coldDeveloper too cold– – Developed too little Developed too little

timetime

InadeqUate FIxatIonInadeqUate FIxatIon

Initially film is cloudy Initially film is cloudy and milky.and milky.

Over time appears Over time appears yellow/brown –yellow/brown –Dichroic stain.Dichroic stain.

Incomplete WashIng / Incomplete WashIng / rInsIngrInsIng

Fixer remains.Fixer remains.

Cloudy, sticky residue.Cloudy, sticky residue.––Yellow-brown stainYellow-brown stain––Sulfur smellSulfur smell

Incomplete WashIng/rInsIngIncomplete WashIng/rInsIng

KIssIng deFectsKIssIng deFects

cassette debrIs (cr)cassette debrIs (cr)

White & focalWhite & focal

• • Sharp marginsSharp margins

• • Essentially the same Essentially the same as FS dirty cassetteas FS dirty cassette

WorKstatIon artIFactsWorKstatIon artIFacts

Screen-FilmScreen-Film

Not ApplicableNot Applicable

CR & DRCR & DR

Faulty Transfer (DR)Faulty Transfer (DR)ClippingClippingPlankingPlankingUberschwingerUberschwinger

FaUlty transFerFaUlty transFer

Appearance: Anything Appearance: Anything goes, generally distorted goes, generally distorted anatomyanatomy

Cause: Problems in data Cause: Problems in data transfer to workstationtransfer to workstation

– – Memory problemsMemory problems– – Communication errors Communication errors

(e.g. (e.g. loose cables)loose cables)

– – Power fluctuationPower fluctuation

FaUlty transFer (dr)FaUlty transFer (dr)

UberschWInger (cr, dr)UberschWInger (cr, dr)

Black & focal.Black & focal.

Black lines occur around dense structures can Black lines occur around dense structures can be mistaken for loosening or infection of be mistaken for loosening or infection of implants.implants.

Cause: Certain processing algorithms (edge-Cause: Certain processing algorithms (edge-enhancement).enhancement).