Normal Chest Xray, CT & MRI

Normal'Chest'X!Ray,%CT%and%MRI" Benigno'R'Santi'II,"MD,#FPCR! UST!FMS$!Department)of)Radiological)Sciences)!! nd (Magboo'C'2015,"Transcribed"from"PPT"and"Lecture;"few!information)lifted)from)Basic)Radiology)By)Chen,)2 !Ed.)!

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" Radiographic+Film!in#between#two# Fluorescent+coatings!(also&called& intensifying)screens)!

!!!!!!!Radiography!

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These$coatings)are$made$of$high$ atomic'number'materials."It!can$ absorb&x#rays%more!efficiently) (compared*to*the*film)*and$emit$ photons,!which%can%now$be#efficiently# absorbed(by(the(x#ray$film$itself.!

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Computed)Tomography! Magnetic)Resonance!

! Spatial'Resolution'and'Effective'Radiation'Dose'of'Thoracic' Imaging'Modalities" Spatial'Resolution'–!Ability'to'define'/'differentiate'2'objects' apart%from%each%other%at%the%least%possible%distance! (Think'of#pixels."If"an"image"has"better!resolution,+it+would+have+ more% pixels,% therefore% would% appear% sharper' and' you' can' delineate(even(small(objects)!

" Modality!

Resolution*(mm)!

Dose%(mSv)!

CXR!

0.08!

DR!

0.17!

CT! MRI! Nuclear(Medicine! PET! Angiography! US!

0.4! 1.0! 7.0! 3.0! 0.13! 0.3!

0.02$(PA),$! 0.04$(lateral)! 0.02$(PA),! 0.04$(lateral)! 8! 0! 0.4! 7! 12! 0!

Background+ Radiation!

N/A!

3"per"year!

Chest&X#Ray$has$better$spatial$resolution$than$CT$and$MRI! ! Because'CXR'is'an'actual'picture'of'the'Chest! CT#&#MRI#are#digital#images,(which(have(been(computed! ! (Similar:)a)photograph(taken(using(film(vs.(a(digital'camera)! " Indications*for*Chest*Radiography" Diagnostic! ! Cardiopulmonary-symptoms! " Cough,'hemoptysis,'shortness'of'breath,' chest&pain,&etc.! ! Preoperative*for*thoracic*surgery! ! Preoperative*if*known*cardiopulmonary*limitations! ! Staging'of'thoracic'tumors'and'extrathoracic' malignancies! ! Infection! " Pleural,(parenchymal,(mediastinal! Follow#up! ! Previously+diagnosed+cardiopulmonary+disease! " Pneumonia)resolution)to)exclude) endobronchial%lesion! " Pulmonary*edema! Monitoring(of(intensive(care(unit(patients! ! Lung%disease! ! Pleural'disease! ! Lines&and&tubes&positions! Monitoring(of(postoperative(patients!

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!X#ray$films$are$valuable.$They$can$be$used$as$a$comparison$to$ evaluate'progression'of'pre#existing(conditions%or%establish%a%if% a"finding"have"been"present"in"previous"examinations.! ! Reading(Chest(Radiographs" Density(=(White(mass! Lucency'='Dark'(represents'air)! Infiltrate*=*Abnormal(density! ! When%looking%at%an!X#Ray:%Compare%Right%and%Left%sides! • Densities'! o Ribs!(count'the'ribs!and$intercostal$spaces)! • By#description:#on#CXR,#the#Anterior#and# Posterior(Ribs(will(be(read(separately(because(of( the$oblique$orientation$of$the$ribs,$where$the$ anterior(would(present(to!be#at#a#relatively# lower&level! o Heart&and&its&Vascular(Markings! • Equivalent+Lucency!(R#to#L)! o Air!–!Lungs&(equivalent&to&other&side)! • Difficult(to(compare(when(the(shadow(of(the( heart&interferes&(i.e.&lower&lung&fields)! o Divide&the&lungs&into&3&divisions&and¬e$for$ the$vascular$markings.! Inner%Lung%Field%(Great%vessels%coming%from%hila)! Middle&Lung&Field&(intermediate&vessels)! Outer&Lung&Field&(very&small&vessels)!

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Trace&the&vascular&markings&to&differentiate& normal'from'an'infiltrate.!

! ! ! ! ! ! ! !!!!!!!!!!!!O""""""""M""""""""""I"""""""""""! !!!!!!!!!!!!!!!!!!!!!!!!Small!!!!!!!Intermediate!!!!!!!!Large!

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Equivalent+Side!

2"Factors"Affecting"Radiographic"Density"

2.

3.

1.#Tissue&Depth! ! Greater&thickness&=!more%dense! ! Thick&tissues&will&attenuate&more&X#ray$beams$! ! More%attenuation%=%More%Density! ! Less$attenuation$=$More$Lucency! 2.#Atomic#Weight! ! The$Bone!is#the#densest#tissue#you#can#find! ! ! Because'of'the'presence'of'Calcium! ! Soft%Tissues:"Intermediate"density"! (Water&Density)! ! Lungs!very%Lucent%(Air!in#alveoli)! !

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" Chest&X!Ray:"the"density"of"muscle,"blood"and"liver"are" very%close%together%(they%are%only%translated%as% intermediate)or)water&densities)!! Computed)Tomography:"can"differentiate"these"minute" differences)fairly%well! " Technique)in)doing)Proper)Chest)X!ray" 1. Upright(position! If#the#patient'lies'supine:! • There$is$pseudo#increase(in(the(transverse(diameter! • The$level$of$the$diaphragm$may$be$deviated! Note:&the&diaphragm&upon&CXR&examination&is& usually&described&in&halves.! • Right&hemi"diaphragm! th o Usually'at'the'level'of'the'10 ! posterior(rib! o Can$normally$be$higher$than$the$ left%(due%so%the%Liver%being% positioned)on#the#Right#side)! • Left%hemi"diaphragm)! o Should'not"be"higher"than"the"Right! ! !

Inhale'Deeply! • Take%the%X#ray$at#the#end#of#a#moderately# deep$inspiratory$effort! • This%is%done%to%inflate%the%lungs! o Demonstrate*normal*lucency! Postero#Anterior! • The$film$is$positioned$in$front$of$the$patient! • The$X#ray$source$is$at$the$back$of$the$patient! o Lessens%the%Magnification%of%the%Heart! o Can$be$mistakenly$interpreted$as$ cardiomegaly,! Note:!an#x"ray$is$like$casting$a$shadow,$ the$greater$the$between$the$tube$and$ the"film,"the"lesser%the%magnification.! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! The$distance$between$the$tube$and$the$film! determines)magnification)and)clarity)or) sharpness.!It#is#usually#done#at!6"feet.! (An#AP#film,#taken#from#the#same#distance,#which#is#6# feet,%enlarges%the%shadow%of%the%heart%"!which%is%far% anterior(in(the(chest(and(makes(the(posterior(ribs( appear%more%horizontal)!

! Changes(on(the(Chest(X#ray$corresponds$to$the$ air$content$of$the$lungs,$specifically$in$the$ Acinus'(which'contain'alveoli)! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

In#CXR,#The$Lungs$are$referred$to$as:! Upper%Lobe!and! Lower&lung&Field&(not%lobe)! • They%are%separated%by%the$minor$fissure$and$ the$hila! • Because'the'middle'lobe,'lower'lobes'and' lingual'are'superimposed'on'each'other! • The$Lower$lung$field$will$be$divided$by$the$ oblique(fissure(and(major(fissure! • The$lower$lobes$are$more$posteriorly$located! ! ! ! ! ! ! ! ! ! !

Companion(Shadow" Appearance(of(a(smooth,(homogenous,(radiodensity(with( a"well#defined&margin!that$runs!parallel&with&a&bony& landmark.$They$represent$soft$tissue$that$overlies$the$ respective)bony)landmark)in)profile.)They)may)or)may) not$always$be$present.! ! Rib$companion$shadow! ! Scapular(companion(shadow! ! Clavicular)companion)shadow! ! !

The$left$image%shows%the%right%minor&fissure&(A)&and&the&inferior& borders'(B)'of'the'Major'fissures'bilaterally.!The$right$image$ shows%the%superior%border%of%the%major%fissures%(B)%bilaterally.! ! !

! ! ! ! ! ! ! ! ! !Azygous(Fissure! !

Companion(Shadow(of(the(Clavicle."It#is#actually'just'soft' tissue,'and'should'not'be'mistaken'for'other'abnormalities!

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! Abnormal)Density)(Metallic)Density);)a)slug)of)a)bullet.! Note:&the&density&superior&to&the&right&clavicle&(we$can$be$ able%to%determine%if%it%is%located%outside%of%the%thoracic% cavity'by'tracing'the'outlines)'this%density%is%just%actually% the$bandage'of'the'patient'(possibly!from%the%bullet’s% point&of&entry)! ! ! ! ! ! " " " " " " Posteroanterior*vs.*anteroposterior*radiograph.!On#the# anteroposterior*radiograph*(A)*of*this*normal*patient,*the* detector'is'against'the'back'of'the'patient.'A'combination'of' decreased'distance'between'the'source'and'the'patient'and' increased)distance&between&the&detector&and&the&anterior& mediastinal*structures*compared*with*the*posteroanterior* radiograph)(B))leads)to)magnification)of)the)heart.)" " " " " "

Apico!lordotic(View! Anteroposterior*view*of*the*chest! Patient'is'in'hyperextended'position! X#ray!beam%goes%upward!

Computed)Tomography"

" " " " " " " " ! " " ! Principles*of*computed*tomography.*The$source$of$x#rays%and% The$densities$emanating$from$the$ribs$and$clavicle$will$now$be$ the$detectors$are$on$opposite$sides$of$the$gantry$with$the$ on#the#upper#segments! patient'at'the'center'of'the'gantry.'Radiation'that'crosses'the' ! patient'is'detected,'producing'a'projection'of'attenuation' " information.*By*rotating*the*gantry*around*the*patient,& " multiple(projections(are(obtained,(which(are(then(used(to( " mathematically*reconstruct*tomographic*attenuation*images.*! " ! " Advantage:*we*can*adjust*the*images*and*zero#in#on#specific# " structures! " Indications*for*Thoracic*Computed*Tomography" " Pulmonary" " ! Further'characterize'CXR'abnormality'(e.g.,' " nodule,(mediastinal(mass)! Lordotic'view.'In#this#patient#with#a#left#apical#neurofibroma,# ! !Detection(and(follow#up#of#neoplastic# the$abnormality$is$subtle$on$the$posteroanterior$radiograph$ disease&(e.g.,&metastatic&sarcoma,&lymphoma)! (A),%but%the%lordotic(view((B)(improves(visualization(of(the(lung( ! Characterization,of,lung,nodules! apices,(and(the(neurofibroma((asterisk)(becomes(more( !!!!!!Benign&vs.&indeterminate! apparent." ! Parenchymal+lung+disease+(e.g.,+emphysema,% " interstitial)lung)disease,)infection)! " ! !Airway'disease! " !!!!!!Central(and(peripheral(airways! " ! Pleural'disease! " !!!!!!Empyema,(metastasis,(mesothelioma! " ! Post#surgical)complications! " ! Percutaneous+biopsy+guidance! " ! Localization*for*VATS! " Cardiac" " ! !Cardiac'abnormalities%on%CXR! " ! Cardiac'anatomy! " ! !!!Coronary'arteries! " !!!!!!Calcification,+patency+with+CTA! " !!!!!!Aberrant(coronary(arteries! " ! !!!Postcardiac*bypass*grafting*complications! " !!!!!!Mediastinitis! " Vascular" " ! Aorta:'aneurysm,'trauma,'dissection,' " coarctation! " ! Pulmonary*arteries:(embolus,(pulmonary( " hypertension! " ! Venous:(SVC/brachiocephalic(vein(thrombus( " or#obstruction! " ! " ! " ! " ! " !

" " " " " " " Computed)tomography)imaging."On"a"mediastinal" window&(A),&the&lungs&are&mostly&black&and&the& mediastinum*and*chest*wall*are*emphasized.*On*a* lung#window#(B),#these#structures#are#white#and#the# fine%structures%of%the%lungs%are%emphasized.!" " " " " " " "

Maximal'intensity'projection'reconstructions.&Information* from%a%stack%of%images%representing%a%volume%can%be%combined% into%a%single%image%representing%for%each%pixel%the%maximum% value&of&that&pixel&through&the&volume,&shown&here&in&the& coronal'(A)'and'sagittal'(B)'planes.'! !

Lung%nodule%on%computed%tomography.%The$faint$nodule$ projecting+at+the+right+lung+base+near+the+diaphragm+(A)+ was$further$investigated$by$Computed$Tomography,+ which%revealed%a%calcified%granuloma" "

High%resolution%computed%tomography%allows&exquisite& visualization+of+the+fine+detail+of+the+lung+parenchyma+in+this+ patient'with'Langerhan's'cell'histiocytosis.'! !

Coronal'and'sagittal'reconstructions.'Multiplanar) reconstruction*of*the*helical*projection*data*in*the*coronal*(A)* and$sagittal$(B)$planes$can$be$performed.$This$improves$ visualization+of+some+structures,+such+as+the+lung+apices+and+ the$great$vessels.$!

Three!dimensional*reconstructions.*Data$can$be$further$ processed(to(produce(three#dimensional*images*with*shaded* surface(of(any(chest(structure,(such(as(the(heart,(mediastinum,( lungs&or&ribs.&! " " " " " " " " " " " "

Magnetic)Resonance)Imaging)(MRI)!

! Magnetic)properties)of)nucleus.)A)hydrogen)nucleus)has)two) important)magnetic)properties:)a)magnetic)moment,) represented(by(an(arrow(along(its(axis,(and(an(angular( momentum'or'spin.'! Indications*for*Thoracic*Magnetic*Resonance*Imaging" Thoracic" ! Chest&wall&neoplasm((especially(superior( sulcus%tumors)! ! Mediastinal*tumors*(e.g.,*bronchogenic*cysts)! ! Lung%parenchyma:%limited,%experimental! ! Thoracic(outlet(and(brachial(plexus! Cardiac" ! !Congenital*heart*disease:*shunts,* complicated+anatomy! ! !Myocardium! !!!!!!Cardiomyopathy! !!!!!!Ischemic(disease! !!!!!!Hypertension! !!!!!!Right&ventricular&dysplasia! ! Pericardium:+thickening,+effusion,+ tamponade,*pericardial*cyst! ! !Masses:&thrombus,&tumors! ! Valves'(limited):'stenosis,'regurgitation! Vascular" ! "Aorta:'aneurysm,'trauma,'dissection,# coarctation! ! !Pulmonary*arteries:*embolus,*pulmonary* hypertension! ! !Venous:(SVC(thrombus(or(obstructionSVC,( superior(vena(cava.! ! !

Magnetic)Resonance)in)the)chest)is)only)helpful)as)far)as)the) mediastinum*and*the*thoracic*wall*is*concerned.! The$lung$parenchyma%is%seen%as%low#signal'areas'because'of'the' presence'of'air.! ! "

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Magnetic)resonance)angiography.)Magnetic)resonance) angiography*of*the*aorta*and*its*branches*is*useful*to*evaluate* aortic'dissection'(A).'Magnetic'resonance'angiography'of'the' pulmonary*arteries*enables*good*visualization*of*the* pulmonary*arteries*(B)*and*can*be*used*to*rule*out*pulmonary" embolism.)! " " " " " "

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