Chest Radiography Interpretation: Reading Chest Films

Chest Radiography Chest Radiography Interpretation: Interpretation: Reading Chest FilmsReading Chest Films

Lisa Chen , M.D.Assistant Clinical Professor

Pulmonary and Critical Care DivisionDepartment of Medicine

San Francisco General Hospital

Michael Gotway, MDAssociate Clinical Professor, RadiologyUniversity of California, San Francisco

Approach to the CXR:Technical Aspects

Approach to the CXR:Approach to the CXR:Technical AspectsTechnical Aspects

• Inspiratory effort9-10 posterior ribs

• Penetrationthoracic intervertebral disc space just visible

• Positioning/rotationmedial clavicle heads equidistant to spinous process

• Inspiratory effort99--10 posterior ribs10 posterior ribs

• Penetrationthoracic intervertebral disc space just visiblethoracic intervertebral disc space just visible

• Positioning/rotationmedial clavicle heads equidistant to spinous medial clavicle heads equidistant to spinous processprocess

Low Lung VolumesLow Lung Volumes

Over ExposureOver Exposure Proper ExposureProper Exposure

101010

What to EvaluateWhat to EvaluateWhat to Evaluate

• Lungs• Pleural surfaces• Cardiomediastinal contours• Bones and soft tissues• Abdomen

• Lungs• Pleural surfaces• Cardiomediastinal contours• Bones and soft tissues• Abdomen

Where to LookWhere to LookWhere to Look

• Apices• Retrocardiac areas (left and right)• Below diaphragm

• Apices• Retrocardiac areas (left and right)• Below diaphragm

Apical TBApical TB

Left Left RetrocardiacRetrocardiac OpacityOpacity

Normal Anatomy: Frontal CXRNormal Anatomy: Frontal CXRNormal Anatomy: Frontal CXR

• Heart• Aorta• Pulmonary arteries• Airways• Diaphragm/costophrenic sulci• Junction lines

• Heart• Aorta• Pulmonary arteries• Airways• Diaphragm/costophrenic sulci• Junction lines

Normal Anatomy: LateralNormal Anatomy: LateralNormal Anatomy: Lateral

• Heart• Aorta• Pulmonary arteries• Airways• Spine

• Heart• Aorta• Pulmonary arteries• Airways• Spine

AAAA

RVRV

LVLV

Chest Radiography: Basic Principles

Chest Radiography: Chest Radiography: Basic PrinciplesBasic Principles

• X-ray photon fates:completely absorbed in patienttransmitted through patient; strike filmscattered within patient; strike film

• X-ray absorption depends on:beam energy (constant)tissue density

• X-ray photon fates:completely absorbed in patientcompletely absorbed in patienttransmitted through patient; strike filmtransmitted through patient; strike filmscattered within patient; strike filmscattered within patient; strike film

• X-ray absorption depends on:beam energy (constant)beam energy (constant)tissue densitytissue density

Maximum xMaximum x--rayrayTransmissionTransmission

(least dense tissue)(least dense tissue)

Maximum xMaximum x––ray ray AbsorptionAbsorption

(densest tissue)(densest tissue)

BlackestBlackest

airair

fatfat

soft tissuesoft tissue

calciumcalcium

bonebone

xx--ray contrastray contrast

metalmetal

WhitestWhitest

• All cardiothoracic pathology and normal anatomy is visualized (or not) by 7 different densities

• How is this accomplished?differential x-ray absorption

• All cardiothoracic pathology and normal anatomy is visualized (or not) by 7 different densities

• How is this accomplished?differential xdifferential x--ray absorptionray absorption

Chest Radiography: Basic Principles

Chest Radiography: Chest Radiography: Basic PrinciplesBasic Principles

• A structure is rendered visible on a radiograph by the juxtaposition of two different densities

• A structure is rendered visible on a radiograph by the juxtaposition of two different densities

Differential X-Ray AbsorptionDifferential XDifferential X--Ray AbsorptionRay Absorption

Silhouette SignSilhouette SignSilhouette Sign

• Loss of the expected interface normally created by juxtaposition of two structures of different density

• No boundary can be seen between two structures of similar density

• Loss of the expected interface normally created by juxtaposition of two structures of different density

• No boundary can be seen between two structures of similar density

Right Lower Lobe PneumoniaRight Lower Lobe Pneumonia

Differential X-Ray AbsorptionDifferential XDifferential X--Ray AbsorptionRay Absorption

• The absence of a normal interface may indicate disease;

• The presence of an unexpected interface may also indicate disease

• The presence of interfaces can be used to localize abnormalities

• The absence of a normal interface may indicate disease;

• The presence of an unexpected interface may also indicate disease

• The presence of interfaces can be used to localize abnormalities

Chest Radiographic Patterns of DiseaseChest Radiographic Chest Radiographic Patterns of DiseasePatterns of Disease

• Air space opacity• Interstitial opacity• Nodules and masses• Lymphadenopathy• Cysts and cavities• Lung volumes• Pleural diseases

• Air space opacity• Interstitial opacity• Nodules and masses• Lymphadenopathy• Cysts and cavities• Lung volumes• Pleural diseases

• Cardiomediastinal contour abnormalities• Bone and soft tissue abnormalities• Below the diaphragm: abdominal and

retroperitoneal disease

• Cardiomediastinal contour abnormalities• Bone and soft tissue abnormalities• Below the diaphragm: abdominal and

retroperitoneal disease

Chest Radiographic Patterns of DiseaseChest Radiographic Chest Radiographic Patterns of DiseasePatterns of Disease

Air Space OpacityAir Space OpacityAir Space Opacity

• Components:air bronchogram: air-filled bronchus surrounded by airless lungconfluent opacity extending to pleural surfacessegmental distribution

• Components:air air bronchogrambronchogram: air: air--filled bronchus filled bronchus surrounded by airless lungsurrounded by airless lungconfluent opacity extending to pleural confluent opacity extending to pleural surfacessurfacessegmental distributionsegmental distribution

Air Space Opacity: DDXAir Space Opacity: DDXAir Space Opacity: DDX

• Blood (hemorrhage)• Pus (pneumonia)• Water (edema)

hydrostatic or non-cardiogenic• Cells (tumor)• Protein/fat: alveolar proteinosis and

lipoid pneumonia

• Blood (hemorrhage)• Pus (pneumonia)• Water (edema)

hydrostatic or nonhydrostatic or non--cardiogeniccardiogenic• Cells (tumor)• Protein/fat: alveolar proteinosis and

lipoid pneumonia

LUL PneumoniaLUL Pneumonia

Interstitial OpacityInterstitial OpacityInterstitial Opacity

• Hallmarks:small, well-defined noduleslines

interlobular septal thickeningfibrosis

reticulation

• Hallmarks:small, wellsmall, well--defined nodulesdefined noduleslines lines

interlobular septal thickeninginterlobular septal thickeningfibrosisfibrosis

reticulationreticulation

Interstitial Opacity: Small NodulesInterstitial Opacity: Small Nodules

Interstitial Opacity: Interstitial Opacity: LinesLines

Interstitial Opacity: Lines & ReticulationInterstitial Opacity: Lines & Reticulation

Interstitial Opacity: DDXInterstitial Opacity: DDXInterstitial Opacity: DDX

• Idiopathic interstitial pneumonias• Infections (TB, viruses)• Edema• Hemorrhage• Non–infectious inflammatory lesions

sarcoidosis• Tumor

• Idiopathic interstitial pneumonias• Infections (TB, viruses)• Edema• Hemorrhage• Non–infectious inflammatory lesions

sarcoidosissarcoidosis• Tumor

Nodules and MassesNodules and MassesNodules and Masses

• Nodule: any pulmonary lesion represented in a radiograph by a sharply defined, discrete, nearly circular opacity 2-30 mm in diameter

• Mass: larger than 3 cm

• Nodule: any pulmonary lesion represented in a radiograph by a sharply defined, discrete, nearly circular opacity 2-30 mm in diameter

• Mass: larger than 3 cm

Nodules and MassesNodules and MassesNodules and Masses

• Qualifiers:single or multiplesizeborder definitionpresence or absence of calcificationlocation

• Qualifiers:single or multiplesingle or multiplesizesizeborder definitionborder definitionpresence or absence of calcificationpresence or absence of calcificationlocationlocation

MassMass

CalcificationCalcification

WellWell--DefinedDefined

IllIll--DefinedDefined

LymphadenopathyLymphadenopathyLymphadenopathy

• Non-specific presentations:mediastinal wideninghilar prominence

• Specific patterns:particular station enlargement

• Non-specific presentations:mediastinal wideningmediastinal wideninghilar prominencehilar prominence

• Specific patterns:particular station enlargementparticular station enlargement

Right Paratracheal Right Paratracheal LymphadenopathyLymphadenopathy

Right Hilar LANRight Hilar LAN

Right Hilar LANRight Hilar LAN

Left Hilar LANLeft Hilar LAN

Subcarinal LANSubcarinal LAN

Subcarinal LANSubcarinal LAN

*

AP Window LANAP Window LAN

Cysts & CavitiesCysts & CavitiesCysts & Cavities

• Cyst: abnormal pulmonary parenchymal space, not containing lung but filled with air and/or fluid, congenital or acquired, with a wall thickness greater than 1 mm

epithelial lining often present

• Cyst: abnormal pulmonary parenchymal space, not containing lung but filled with air and/or fluid, congenital or acquired, with a wall thickness greater than 1 mm

epithelial lining often presentepithelial lining often present

Cysts & CavitiesCysts & CavitiesCysts & Cavities

• Cavity: abnormal pulmonary parenchymal space, not containing lung but filled with air and/or fluid, caused by tissue necrosis, with a definitive wall greater than 1 mm in thickness and comprised of inflammatory and/or neoplastic elements

• Cavity: abnormal pulmonary parenchymal space, not containing lung but filled with air and/or fluid, caused by tissue necrosis, with a definitive wall greater than 1 mm in thickness and comprised of inflammatory and/or neoplastic elements

Cysts & CavitiesCysts & CavitiesCysts & Cavities

• Characterize:wall thickness at thickest portioninner liningpresence/absence of air/fluid levelnumber and location

• Characterize:wall thickness at thickest portionwall thickness at thickest portioninner lininginner liningpresence/absence of air/fluid levelpresence/absence of air/fluid levelnumber and locationnumber and location

Benign Lung Cyst : Benign Lung Cyst : PCPPCP PneumatocelePneumatocele•• Uniform wall thicknessUniform wall thickness•• 1 mm1 mm•• Smooth inner liningSmooth inner lining

Benign Cavities :Benign Cavities :CryptococcusCryptococcus

•• max wall thickness max wall thickness ≤≤4 mm4 mm•• minimally irregular inner liningminimally irregular inner lining

Indeterminate CavitiesIndeterminate Cavities

•• max wall thickness max wall thickness 55--15 mm15 mm•• mildly irregular inner liningmildly irregular inner lining

Malignant Cavities: Squamous Cell CaMalignant Cavities: Squamous Cell Ca•• max wall thickness max wall thickness ≥≥16 mm16 mm•• Irregular inner liningIrregular inner lining

Pleural Disease: Basic PatternsPleural Disease: Basic PatternsPleural Disease: Basic Patterns

• Effusionangle blunting to massivemobility

• Thickeningdistortion, no mobility

• Mass• Air• Calcification

• Effusionangle blunting to massiveangle blunting to massivemobilitymobility

• Thickeningdistortion, no mobilitydistortion, no mobility

• Mass• Air• Calcification

Pleural EffusionPleural Effusion

Pleural EffusionPleural Effusion

Subpulmonic EffusionSubpulmonic Effusion

Pleural CalcificationPleural Calcification