INTERPRETATION INTERPRETATION OFOF

NORMAL NORMAL CHEST X-RAYCHEST X-RAY

By-Dr Saket JainBy-Dr Saket Jain Dr Setu SataniDr Setu Satani

Dept. of RADIO DIAGNOSISDept. of RADIO DIAGNOSISMGM HOSPITALMGM HOSPITAL

A routine pattern of plain x-ray film reporting can be ensured for proper scrutiny. The 14-Step is listed below.

1.Name2.Date.3.IPD/OPD NO.4.Markers (R/L) 5.Orientation 6.Penetration7.Inspiration8.Rotation 9.Angulation

Pre Read

Quality Control

Cont’dCont’d

10.Soft tissues / bony structures11.Mediastinum12.Diaphragms13.Lung Fields14.Abdominal structures

FIN

DIN

GS

CHEST INTRODUCTION

Technical Adequacy

In trying to determine if pathology is present in a chest radiograph several factors have to be considered in the overall judgment of the radiograph to determine if the visual findings are pathologic or in part are related to the radiograph itself.

Factors to be considered on all chest x-rays include: Orientation Inspiration Penetration Rotation Angulation

Orientation:

In this we are making reference to the position of the patient and the x ray beam.

A PA radiograph is obtained with the x-ray traversing the patient from posterior to anterior and striking the film.

Similarly an AP radiograph is positioned with the xray traversing the patient from anterior to posterior striking the film.

The cardiac border will appear larger on an AP radiograph due to the magnification effect of the more anteriorly located heart relative to the film.

Difference between P.A & A.P Difference between P.A & A.P VIEWVIEW

In PA view In PA view Clavicles don’t project too high into the apices Clavicles don’t project too high into the apices

or thrown above the apices (more horizontal)or thrown above the apices (more horizontal) Heart wont be magnified over the Heart wont be magnified over the

mediastinum therefore preventing the mediastinum therefore preventing the appearance of cardiomegalyappearance of cardiomegaly

Scapula are away from the lung fieldsScapula are away from the lung fields Ribs are obliquely oriented in PA viewRibs are obliquely oriented in PA view Spine and posterior ends of ribs are clearly Spine and posterior ends of ribs are clearly

seenseen

Why is PA preferred over APWhy is PA preferred over AP Reduces magnification of heart therefore Reduces magnification of heart therefore

preventing appearance of cardiomegalypreventing appearance of cardiomegaly Reduces radiation dose to radiation Reduces radiation dose to radiation

sensitive organs such as sensitive organs such as thyroid,eyes,breaststhyroid,eyes,breasts

Visualised maximum areas of lungVisualised maximum areas of lung Moves scapula away from the lung fieldsMoves scapula away from the lung fields More stable positioning for the patient as More stable positioning for the patient as

they can hold onto the unit – this reduces they can hold onto the unit – this reduces patient movement.patient movement.

Compression of breast tissue against the Compression of breast tissue against the film cassette reduces the density of tissue film cassette reduces the density of tissue around the CP bases therefore visualizing around the CP bases therefore visualizing them more clearlythem more clearly

PA AP

Orientation

PA

AP

Inspiration:The volume of air in the hemithorax will affect the configuration of the heart in relation to cardiac size.

The vascular pattern in the lung fields will be accentuated with a shallow inspiration.

The level of inspiration can be estimated by counting ribs.

Visualization of nine posterior ribs, or seven anterior ribs on an upright PA radiograph projecting above the diaphragm would indicate a satisfactory inspiration

Inspiration Expiration

Inspiration

Expiration

NOTE - CHANGE IN HEART SIZE AND VASCULARITY DUE TO EXPIRATION

Penetration:

Refers to adequate photons traversing the patient to expose the radiograph.

The lack of penetration renders the area “whiter” than with an adequate film and can simulate pneumonia or effusion. In an ideal radiograph the thoracic spine should be barely perceptual viewing through the cardiac shadow , the left hemi- diaphragm behind heart and vessels only up to 2/3 of lung area

In lateral view 2 sets of ribs should be seen, sternum seen, spine appears clearer as it goes down.

Penetration

SEE THE NODULE ON THE PREVIOUS FILM

Rotation Ideally the clavicle heads should be equidistant from the spinous process.

Rotation of the radiograph is assessed by judging the position of the clavicle heads and the thoracic spinous process.

Rotation Of patient distorts mediastinal anatomy and makes assessment of cardiac chambers and the hilar structures especially difficult. Chest wall tissue also contributes to increased density over the lower lobe fields simulating disease.

Rotation

Angulation: With the patient in a more lordotic projection and in Apicogram the clavicles will project superiorly relative to the upper thorax again causing some distortion of the normal mediastinal anatomy.

With the lordotic projection of the ribs assume a more horizontal orientation.

Occasionally a lordotic x ray can be obtained intentionally to better visualize structures in the thoracic apex obscured by overlying boney structures.

Angulation

VIEWS OF CXR

P.A VIEW

AP VIEW

LATERAL VIEW

LATERAL DECUBITUS VIEW

LORDOTIC VIEW

Normal Radiographic AnatomyWITHVIEWING CHEST RADIOGRAPH

SOFT SOFT TISSUETISSUE

Soft tissues cast shadow on plain Soft tissues cast shadow on plain radiographs which have less dense radio-radiographs which have less dense radio-opacity.opacity.

Breast shadow result in increased opacity Breast shadow result in increased opacity over the lower thorax bilaterally.over the lower thorax bilaterally.

Nipple shadow may appear as round Nipple shadow may appear as round opacities in the 4th or lower ant. opacities in the 4th or lower ant. Intercostal space.Intercostal space.

Breast and nipple shadow are usually Breast and nipple shadow are usually bilateral and symmetrical.bilateral and symmetrical.

NIPPLE SHADOWS

NIPPLE SHADOW

Cont’dCont’d

Linear shadow may result from loose Linear shadow may result from loose skin foldskin fold

A faint soft- tissue shadow parallel to A faint soft- tissue shadow parallel to the clavicle results from over-lining the clavicle results from over-lining skin fold and subcutaneous tissue. skin fold and subcutaneous tissue. ( Clavicular companion shadow.)( Clavicular companion shadow.)

BONY THORAX

Bony Bony thoraxthorax

Chest x-ray primarily visualizes Chest x-ray primarily visualizes intrathoracic structure but also outline intrathoracic structure but also outline the shoulder girdle ,ribs, cervical and the shoulder girdle ,ribs, cervical and thoracic vertebrae.thoracic vertebrae.

Sternum is often well outlined .Sternum is often well outlined . Shape of the thorax varies with age and Shape of the thorax varies with age and

body habitus.body habitus. Angulations of the ribs varies with body Angulations of the ribs varies with body

types. downward angulations: minimal in types. downward angulations: minimal in short hypersthenic individual. And short hypersthenic individual. And maximal in asthenic patient.maximal in asthenic patient.

Cont’dCont’d

Intercostal space are numbered according Intercostal space are numbered according to the intercostal rib above them .The ribs to the intercostal rib above them .The ribs and the interspaces are designated into 2 and the interspaces are designated into 2 groups : anterior and posterior.groups : anterior and posterior.

The costal cartilages are not visible except The costal cartilages are not visible except when calcified which then assume when calcified which then assume characteristic mottled appearance characteristic mottled appearance (periphery in male but central in female).(periphery in male but central in female).

Diaphragm in a normal adult is slightly Diaphragm in a normal adult is slightly higher on right compared to the Left.higher on right compared to the Left.

MEDIASTINUMMEDIASTINUM.. This is the space between the right and left pleurae This is the space between the right and left pleurae

in and near the median sagittal plane of the chest.in and near the median sagittal plane of the chest. It is bounded by posterior surface of the sternum It is bounded by posterior surface of the sternum

and the anterior surface of the thoracic vertebrae.and the anterior surface of the thoracic vertebrae. It contains all the thoracic viscera except for the It contains all the thoracic viscera except for the

lungs.lungs. It is divided into superior and inferior parts by an It is divided into superior and inferior parts by an

imaginary horizontal line passing through the imaginary horizontal line passing through the sternal angle of Louis backwards to the lower sternal angle of Louis backwards to the lower border of T4 vertebrae.border of T4 vertebrae.

The inferior mediastinum is further divided into the The inferior mediastinum is further divided into the anterior, middle and posterior mediastinum by the anterior, middle and posterior mediastinum by the fibrous pericardiumfibrous pericardium

DIVISION OF MEDIASTINUMDIVISION OF MEDIASTINUM

1.1. Felson’s ClassificationFelson’s Classification

2.2. Sutton’s ClassificationSutton’s Classification

3.3. Haaga’s ClassificationHaaga’s Classification

4.4. Heitzman’s ClassificationHeitzman’s Classification

1. FELSONS CLASSIFICATION1. FELSONS CLASSIFICATION

The mediastinum can be divided into The mediastinum can be divided into anterior, middle and posterior anterior, middle and posterior compartments.compartments.

An imaginary line An imaginary line is traced upward is traced upward from the diaphragm from the diaphragm along the back of along the back of the heart and front the heart and front of the trachea to the of the trachea to the neck. This divides neck. This divides the “anterior” from the “anterior” from the “middle” the “middle” midiastinum midiastinum

A secondary A secondary imaginary line imaginary line connects a point on connects a point on each of the thoracic each of the thoracic vertebrae 1 cm vertebrae 1 cm behind its anterior behind its anterior margin. This divides margin. This divides the “middle” from the “middle” from “posterior” “posterior” mediastinum.mediastinum.

2.Suttons Classification2.Suttons Classification Mediastinum is divided into Mediastinum is divided into 3 parts3 parts1.1. Anterior division Anterior division 2.2. Middle divisionMiddle division3.3. Posterior divisionPosterior division

Anterior DivisonAnterior Divison lies infront of the lies infront of the anterior pericardiumanterior pericardium

Middle division Middle division within the pericardial within the pericardial cavitycavity

Posterior divisionPosterior division lies beyond the post lies beyond the post pericardium and tracheapericardium and trachea

3.Heitzmans division3.Heitzmans division

Heitzman divided the mediastinum Heitzman divided the mediastinum into the following anatomic regions: into the following anatomic regions: the thoracic inlet, the supraaortic the thoracic inlet, the supraaortic area (above the aortic arch), the area (above the aortic arch), the infraaortic area (below the aortic infraaortic area (below the aortic arch), the supraazygos area (above arch), the supraazygos area (above the azygos arch), and the the azygos arch), and the infraazygos area (below the azygos infraazygos area (below the azygos arch).arch).

SUPERIOR MEDIASTINUMSUPERIOR MEDIASTINUM It is located above a It is located above a

horizontal line drawn from horizontal line drawn from the angle of Louis the angle of Louis posteriorly to the spine. posteriorly to the spine.

Also defined as the space Also defined as the space between thoracic inlet and between thoracic inlet and superior aspect of the superior aspect of the aortic arch (ref. aortic arch (ref. JOHN.R.HAAGA)JOHN.R.HAAGA)

Structures include the Structures include the thyroid gland, aortic arch thyroid gland, aortic arch and great vessels, proximal and great vessels, proximal portions of the vagus and portions of the vagus and recurrent laryngeal nerves, recurrent laryngeal nerves, esophagus and trachea. esophagus and trachea.

ANTERIOR MEDIASTINUMANTERIOR MEDIASTINUM This is bounded above by thoracic This is bounded above by thoracic

inlet, laterally by the pleural , inlet, laterally by the pleural , anteriorly by the sternum and anteriorly by the sternum and posteriorly by the pericardium and posteriorly by the pericardium and the great vessels.the great vessels.

It contains loose areolar tissue , It contains loose areolar tissue , lymph nodes, lymphatic vessels , lymph nodes, lymphatic vessels , thyroid, thymus, parathyroid and thyroid, thymus, parathyroid and internal mammary vessels.internal mammary vessels.

It is seen as a triangular area of It is seen as a triangular area of radiolucency between the sternum radiolucency between the sternum and heart on lateral view and heart on lateral view radiograph radiograph . .

MIDDLE MEDIASTINUMMIDDLE MEDIASTINUM It is also referred to as It is also referred to as

vascular space.vascular space. It is bounded by anterior and It is bounded by anterior and

posterior mediastinum. posterior mediastinum. It contains the It contains the

heart ,pericardium ,ascending heart ,pericardium ,ascending and transverse arch of the and transverse arch of the aorta, SVC and azygos veins aorta, SVC and azygos veins that empties into it that empties into it brachiocephalic vessels , the brachiocephalic vessels , the phrenic nerve , the upper phrenic nerve , the upper vagus nerves, the trachea vagus nerves, the trachea and its bifurcation, the main and its bifurcation, the main bronchi, the pulmonary veinsbronchi, the pulmonary veins

POSTERIOR MEDASTINUMPOSTERIOR MEDASTINUM It is also known as post It is also known as post

vascular space.vascular space. It lies btw the heart It lies btw the heart

anteriorly and the anteriorly and the thoracic vertebrae from thoracic vertebrae from the thoracic inlet to the the thoracic inlet to the T12.T12.

It contains descending It contains descending aorta ,oesophagus, aorta ,oesophagus, thoracic duct ,azygos and thoracic duct ,azygos and hemiazygos vein, lymph hemiazygos vein, lymph nodes ,sympathetic nodes ,sympathetic chains and inferior vagus chains and inferior vagus nerves.nerves.

MEDIASTINAL STRUCTURES

TRACHEA

HILUM

The hila are made upof the main pulmonaryarteries and majorBronchi

-The left hilum is higherthan the right

-Lymph nodes are notnormally seen on achest X-ray

carina

On the left side, the left pulmonary artery is directed posterolaterally, toward the left scapula and goes over the left main stem bronchus. The left pulmonary artery is therefore located higher than the right pulmonary artery.

The right hilar shadow is inferior to the left on the PA projection ( 70%). Hilar shadows are equal in height (30%). The right hilum is never superior to the left hilum

• On the lateral projection, the left pulmonary artery is posterior to a line drawn down the tracheal air column.

The trachea appears as an air-shadow coursing down (c6) the midline of the chest and terminating at the carina (T5). The left and right mainstembronchi, as well as the lobar bronchi may be evident

A very slight deviation to the right at the level of aortic arch, moderate deviation to the right is common in infant.

OTHER FINDINGS –

Thymus is usually visible in infants and occupies the superior part of ant. Mediastinum (causes widening of the mediastinum when present) .There is need for a lateral view to confirm it.

When there is enough air in the oesophagus a tracheo - oesophageal stripe may be seen, however oesophagus may be outlined by barium meal to clearly define it’s relation to other mediastinal structures & detection of abnormality .

HEARTHEART

SizeSize ShapeShape Diameter (>1/2 thoracic diameter is Diameter (>1/2 thoracic diameter is

enlarged heart)enlarged heart)

Remember: AP views make heart appear larger Remember: AP views make heart appear larger than it actually isthan it actually is

Superior Vena Cava

Ascending Aorta

Right Atrium

Aortic Arch

Pulmonary Artery

Left Atrium

Left Ventricle

P.A. CARDIAC VIEW

INFERIOR VENA CAVA

P.A. CARDIAC VIEW

Aortic Knob/Arch

Descending Aorta

Left Atrium

Ascending Aorta

Right Ventricle

Left Ventricle

Inferior Vena Cava

LATERAL CARDIAC VIEW

AORTOPULMONARY AORTOPULMONARY WINDOWWINDOW

A "space" located A "space" located underneath the aortic underneath the aortic arch and above the left arch and above the left pulmonary artery. pulmonary artery.

Contains fat. Contains fat. On the PA projection, it On the PA projection, it

appears as a concave appears as a concave shadow. If adenopathy shadow. If adenopathy is present, it manifests is present, it manifests as a convex shadow. as a convex shadow.

DIAPHRAGMDIAPHRAGM

The left and right diaphragm appear as The left and right diaphragm appear as sharply marginated domes. sharply marginated domes.

The peripheral margins of the The peripheral margins of the diaphragm define the costophrenic sulci. diaphragm define the costophrenic sulci.

The right diaphragm is higher than left The right diaphragm is higher than left {usually 1-2 cm } & Will appear larger {usually 1-2 cm } & Will appear larger on a lateral chest filmon a lateral chest film

A difference greater than 3 cm in the A difference greater than 3 cm in the level of two hemi diaphragms is level of two hemi diaphragms is significantsignificant

The righthemidiaphragm ishigher than the left( the heart is pushingthe left hemidiaphragmdown)-A gas bubble beneaththe left hemidiaphragm

RT

LT

Lateral Costophrenic Sulci (Recesses, Angles)

Cardiophrenic Sulci(Recesses, Angles)

Posterior Costophrenic Sulci (Recesses, Angles)

LUNG FIELDSLUNG FIELDS

UPPER ZONE

MIDDLE ZONE

LOWER ZONE

Pulmonary FissuresPulmonary fissures are formed with visceral

pulmonary pleura.

RIGHT LUNG

MAJOR FISSURE OBLIQUE FISSURE

MINOR FISSUREHORIZONTAL FISSURE

LEFT LUNG

MAJOR FISSUREOBLIQUE FISSURE

Oblique fissure more clearly seen on Lateral view from T4-T5 vertebrae to reach the diaphragm and 5 cm behind the costophrenic angle on left And just behind the angle on right.

Horizontal fissure more clearly Seen on P.A view extending from Right hilum to 6th rib in the axillary line

OBLIQUE FISSUREmajor

HORIZONTAL FISSUREminor

OBLIQUE FISSURE(major)

CARINA

RT. MAIN BRONCHUS LT. MAIN BRONCHUS

6TH

RIB

Horizontal Fissure

Left Oblique Fissure

Right Oblique Fissure

FISSURES DIVIDE LUNGS INTO LOBES

RIGHT lung has: UPPER MIDDLE lobes LOWER

LEFT lung has: UPPER lobes LOWER

HORIZONTAL FISSURE

LUL

RML

RLL

LLL

RUL

Retrosternal Clear Space

Retrocardiac Clear Space

some of the visual abdominal structures

Left Hemidiaphragm

Stomach gas bubble

Splenic flexure of the large intestines

Right Hemidiaphragm

Liver

Significance of different Significance of different viewsviews

Anteroposterior viewAnteroposterior view It is useful in differentiating free and It is useful in differentiating free and

loculated pleural fluidloculated pleural fluid

Lateral viewLateral view The only view that provides information of The only view that provides information of

localization of different lobes and localization of different lobes and segmentssegments

Observation on lateral view include- clear Observation on lateral view include- clear spaces, vertebral translucency , and spaces, vertebral translucency , and outline of diaphragms. outline of diaphragms.

OBLIQUE VIEW

It is helpful in localizing a lesion , in visualizing its borders and in projecting it free of overlying structures

Oblique view is preferred to lateral view in case of bilateral disease

DECUBITUS VIEWIt is helpful in demonstrating small pneumothorax or pleural effusions

LORDOTIC VIEW

It is particularly useful for lung apices

This view helps in conforming middle lobe and lingular abnormalities

This view is also helpful in determining the anteropostero location of a lesion

APICOGRAM VIEWAPICOGRAM is done when there is doubt about the apical area

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