How to read NORMAL CHEST X RAYS

MODERATOR:DR.RAVINARAYAN

BY:DR.PUNEET MAHAJANPGDCC 1ST YEAR

HistoryRoentgen disocvered first example of ionizing

radiation called X rays while experimenting with cathode rays in CROOKES tube.

Crookes tube created free electrons by ionization of residual air in the tube by high DC voltage

This voltage accelrated the electrons coming from the hot cathode to high enough velocity that they created X Rays when they struck with anode.

PRODUCTION OF X RAYSX rays are invisible, highly

penetrating,electromagnetic radiations with very high frequency and very short wavelength of 0.1 to 1 A.

When electrons released by hot cathode are accelrated by high voltage are suddenly decelrated upon collision with metal target ,the anode.

Tungsten is maily used as target anode its high atomic no and melting point of 3300 F.

Molybdenum is used foe mammography

.

Different tissues in body absorb X-rays at different extents:

• Bone- high absorption (white)

• Tissue- somewhere in the middle absorption (grey)

• Air- low absorption (black)

THE PLAIN FILM• The PA (postero-anterior) view:It is the most frequently required radiological

examination. Comparison of current film with old films is valuable.

Position: Patient facing the film, chin up with the shoulders rotated forwards to displaced the scapulae from the lungs. Exposure is made on full inspiration, centering at T5.

Lateral view:

Comparison with PA view:

Advantages : Anterior mediastinal massesEncysted pleural fluidsPosterior basal consolidation

Disadvantages : Lung collapseLarge pleural effusion.

Lateral decubitus position: It is helpful to assess the volume of pleural

effusion and demonstrate whether a pleural effusion is mobile or loculated.

Lateral decubitus position film showing mobile pleural effusion (arrows)

Inspiration vs Expiration

This is a PA film on the left compared with a AP supine film on the right.  The AP shows magnification of the heart and widening of the mediastinum.AP film is taken mostly in very ill patients who cannot stand erect.

AP VS PA VIEW

• Poor inspiratory effort will compress and overcrowd the lung markings

CENTERINGMEDIAL ENDS OF CLAVICLES SHOULD BE AT EQUIDISTANT FROM SPINOUS PROCESS AT T4/5 LEVEL.

ROTATION CAN DISTORT MEDIASTINAL BORDERS.

LUNGS NEAREST TO FILM APPEARS LESS TRANSLUCENT.

RT Sternal end is away from central line of spine.

Penetration is degree to which x rays absorbed through body. Normally the vertebral bodies should be just visible through the heart.

DEPENDS UPON THE KVP

kVp = Energy of x-rays = higher penetrability, it moves through tissue.

The energy determines the QUALITY of x-ray produced.1. increase in kVp = electrons gain high energy2. higher the energy of electrons = greater quality of x-rays3. greater quality = greater penetrability

TRACHEA NARROWING:

Normal coronal diameter is 25mm for males nd 21 mm for females.

DISPLACEMENT INTRALUMINAL

LESIONS MIDLINE IN UPPER

PART THEN DEVIATES TO RIGHT AROUND AORTIC KNUCKLE

PARATRACHEAL STRIPERIGHT PARATRACHEAL STRIPE:RT border of tracheameeting with rt lungSEEN IN 60 % .<5MMLEFT PARATRACHEALSTRIPENOT VISUALISED BECAUSE OF GREAT VESSELS ON LEFT BORDER OF TRACHEA

MEDIASTINUM AND HEARTP-A view

Right border: Superior vena cavaRight atriumThe inferior vena cava.rarely The right atrium& the

superior vena cava shares more than 50%.

Left border Aortic knuclePulmonary bayLA appendageLeft ventricle

CARDIAC MALPOSITIONSSITUS SOLITUSDEXTROCARDIA

WITH SITUS INVERSUS

DEXTROCARDIA WITH SITUS SOLITUS

LEVOCARDIA WITH SITUS INVERSUS

SITUS AMBIGIUOS

visceroatrial situs solitus(gastric bubble arrowed) and isolated dextrocardia.

Chest radiograph of a patient with total situs inversus (gastricbubble arrowed).

Cardiac calcificationValvularPericardialMyocardialEndocardialIntraluminalvascular

Pericardial calcificationm/c cause is

constrictive pericarditis.

First occurs in dependent areas:Diapragm,posterior and anterior cardiac surface

Better seen in lateral view.

Minimally over left ventricle.

Aortic valve calcification

JUNCTION LINESANTERIOR

JUNCTION LINEFORMED BY LUNGS

MEETING ANTERIOR TO THE ASCENDING AORTA.

1 MM THICKRUNS DOWNWARD

BELOW THE SUPRASTERNAL NOTCH CURVING FROM LEFT TO RIGHT

POSTERIOR JUNCTION LINE

FORMED BY LUNGS MEETING POSTERIORLY BEHIND ESOPHAGUS

2 MM THICKSTRAIGHT OR CURVED

LINE,CONVEX TO LEFT EXTENDS FROM LUNG APICES TO AORTIC KNUCKLE OR BELOW

LUNGS1. Upper zone: apices to

lower border of 2nd rib anteriorly.

2. Middle zone :lower border of 2nd rib anteriorly to lower border of 4th rib anteriorly.

• 3. Lower zone :lower border of 4th rib anteriorly to lung

bases.

The right upper lobe (RUL) occupies the upper 1/3 of the right lung. Posteriorly, the RUL is adjacent to the first three to five ribs. Anteriorly, the RUL extends inferiorly as far as the 4th right anterior rib

The right middle lobe is typically the smallest of the three, and appears triangular in shape, being narrowest near the hilum

RIGHT LOWER LOBEThe right lower lobe is the largest of all three lobes, separated

from the others by the major fissure.Posteriorly, the RLL extend as far superiorly as the 6th thoracic

vertebral body, and extends inferiorly to the diaphragm.

Lung Anatomy on Chest X-rayThese lobes can be

separated from one another by two fissures.

The minor fissure separates the RUL from the RML, and thus represents the visceral pleural surfaces of both of these lobes.

Oriented obliquely, the major fissure extends posteriorly and superiorly approximately to the level of the fourth vertebral body.

No defined left minor fissure, there are only two lobes on the left; the left upper lobe and left lower lobe.

Left lower lobes

LEFT LOWER LOBES

Lung Anatomy on Chest X-rayThese two lobes are

separated by a major fissure, identical to that seen on the right side, although often slightly more inferior in location.

The portion of the left lung that corresponds anatomically to the right middle lobe is incorporated into the left upper lobe.

Pulmonary artery• MPA Forms convexity on left mediastinal

border b/w arch of aorta and straight left heart border.

• RPA runs horizontally to the right and is not seen on frontal view divides in mediastinum forming descending br.of RPA wich is visible on x ray

• LPA continues as branch of MPA and gives upper lobe branch as it passes left main bronchus forming upper part of left hilum.

0 mm

MainPulmonary

Artery

Ao

15 mm

MainPulmonary

Artery

Ao

LV

LV

Main pulmonary artery ranges from

0 mm–15mm from tangent line

Main pulmonary artery ranges from

0 mm–15mm from tangent line

Pulmonary veinsRight and left upper lobe neins In the outer two thirds of the lungs, arteries

cannot be distinguished from veins on chest radiography

VEINS CAN BE DISTINGUISHED FROM ARTERIES AS VEINS FOLLOW HORIZONTAL COURSE TO LEFT ATRIUM

Venous Hypertension RDPA usually

> 17 mm

Upper lobe vessels equal to or larger than size of lower lobe vessels = Cephalization

Upper lobe vessels equal to or larger than size of lower lobe vessels = Cephalization

KERLEY LINESKerley A lines Kerley B lines1-2 mm ,non brnaching

lines originating from hilum 2-6 cm long

Thickened Interlobular septa

Transverse non branching 1-2 mm lines at lung base perpendicular to pleura

1-3 cm longThickened Interlobular

septa

The Silhouette SignAn intra-thoracic

radio-opacity, if in anatomic contact with a border of heart or aorta, will obscure that border. An intra-thoracic lesion not anatomically contiguous with a border or a normal structure will not obliterate that border.

Diaphragm

•Right is normally higher than left by 1.5-3cm•On inspiration the domes of the diaphragms are at the level of the 6th rib anteriorly and 10th rib posteriorly.

????CHECK ?????

Costophrenic angles crisp?Air under diaphragms?

Flattened diaphragsLoss of diaphragm definition

Elevated hemidiaphragmTenting

Pleural effusion

Soft Tissues Breast shadows Supraclavicular areas Axillae Tissues along side of breasts Abdomen Gastric bubble Air under diaphragm Neck Soft tissue mass

Bones: Check the bones for any fracture , lesions, density or mineralization.

Bony FragmentsRibsSternumSpineShoulder girdleClavicles

Superior rib notching

PolioRestrictive lung diseaseNeurofibromatosisConnective tissue diseaseOsteogenesis imperfectaHyperparathyroidism

Causes of inferior rib notchingUnitateral Blalock-Taussig operationSubclavian artery occlusionAortic coarctation involving left subclavian artery or anomalous right subclavian artery

BitateralAorta-coarcation, occlusion, aortitisSubclavian-Takayasu's disease, atheromaPulmonary oligaemia-FaIlot's tetralogy; pulmonary atresia, stenosis;Venous-SVC, IVC obstructionShunts-intercostal-pulmonary fistula; pulmonary-intercostalarteriovenous fistulaOthers-hyperparathyroidism; neurogenic; idiopathic

.Cardiac anomaly with hypoplastic clavicle ?????

HOLT ORAM SYNDROME

STERNUMPECTUS EXCAVATUMPECTUS CARINATUMSTRAIGHT BACK SYNDROME

ALL THESE CONDITIONS ARE ASSESSED BY PA AND LATERAL VIEWS

Turner syndrome Marfan syndrome Ehlers Danlos Syndrome Noonan syndromeTrisomy 18 Trisomy 21 HomocystinuriaOsteogenesis imperfecta

PECTUS EXCARINATUM

Best viewed in lateral filmIncreased anterioposterio diameter.Increased pulmonary vascular resistance due to L>R shunt

Pectus excavatumCongenital or acquiredRicketsPseudocardiomegalyFalse prominence of pulmonary artery

Viewing lateral filmClear spaces:Retrosternal

AND retrocardiacObliteraion of retrosternal

space:thymoma,aneurysms of aorta and nodal masses.

Vertebral translucency:posterior basal consolidation

Diaphragm outline:Both diaphragms are visible throughout their length except left anteriorly

Acute posterior costophrenic angles

TracheaRight pulmoanry

artery anterior to caring.

LPA is posterior and superior and veins are inferior.CARDIAC CONTOURS

ANTERIOR BORDERAscending aortaPulmonary arteryRight ventriclePOSTERIOR BORDERPulmonary arteryLeft atriumLeft ventricle from above downwards

The Normal Chest X-ray Lateral View:

1. Oblique fissure2. Horizontal

fissure3. Thoracic spine

and retrocardiac space

4. Retrosternal space