Chest x rays

Dr Virbhan

TECHNICAL ASPECT

PROJECTION ORIENTATIONROTATIONPENETRATIONDEGREE OF INSPIRATION

Reading of chest X-rays in CHDIs there cardiomegaly?

Cardiothoracic ratio >60% in neonates> 55% in infants> 50% in older children/adult

Is the situs normal? The situs as defined by-

Stomach bubbleLiver shadowBronchial morphology of more horizontal and

short right bronchus

Situs inversus totalis and dextrocardia- rarely has heart disease

Mesocardia -commonly has c TGALeft-sided heart in situs inversus- has complex

heart disease. Apex -dome of diaphragm is lower on the side

of apex.

Is there a particular chamber enlargement ?

RA enlargement-Vertical height compared to height from aortic

arch to SVC-RA junctionlateral 3 spaces criteriaThe RV type- upturned apex e.g TOF LV type of apex -tricuspid atresia

Is the cardiac silhouette normal? L-posed aortaEnlarged thymus

What is the pulmonary blood flow—increased, decreased or normal?

Increased pulmonary blood flow - more than 5 end-on vessels in the lungs, or more than 3 in one lung.

The end-on vessels should be more than twice the size of an accompanying bronchus.

More than 6 vessels could be traced in the periphery in increased flow states.

Decreased flow - when the vessels are thin and small.

Less than 3 vessels are seen in the peripheryPulmonary conus and main arteries are not

prominent.

Is there PAH? How severe? In adults NORMAL descending branch of right pulmonary

artery- 9–14 mm in females.10–15 mm in males.

In children, the artery size larger than the trachea indicates enlargement.

Peripheral pruning—that is sudden taper of PA branches as it travels to periphery indicates PAH.

Pruning is seen in functional as well as organic PAH.

Is there PVH ? How severe? PVH is present when the PAWP >12 mm Hg. EqualizationCephalizationPerihilar haze Interstitial edema indicate progressively increasing

PVH. o Kerley lines generally indicate chronic severe PVH

Is there aortic arch abnormality? The aortic arch is identified by the impression on

trachea. A right aortic arch is commonly associated with VSD. A right arch and increased blood flow is typically seen

in truncus arteriosus. An inconspicuous aortic arch could mean double arch.Coarctation with arch hypoplasia.

Is there pulmonary parenchymal lesion—Infection Infarction Aspiration Hemorrhage Collapse

Is there asymmetry of findings, e.g. Decreased vasculature on one side? This could indicate ipsilateral pulmonary artery

stenosis.Pulmonary embolism.Anomalous pulmonary venous drainageLung disease.

Is there rib notching? Signs of previous surgery like rib regeneration?

Are there serial changes? The changes of pulmonary plethora diminish

but in Eisenmenger’s syndrome

Spot diagnosis-Boot-shaped heart- TOF, Egg on side appearance of TGA without VSD Figure-of-8 for supracardiac TAPVC Waterfall sign of a truncus arteriosus Typical straight right border for tricuspid atresiaAorta forming the left border in corrected

transposition of great vessels.

COMMON ERRORS

Following are the common errors seen in day-to-day clinical practice:

Spurious cardiomegaly due to expiratory film. Wrong assessment of lung vasculature due to

over- and underpenetration (underpenetration increases lung vasculature and vice versa)

Rotation of film leading to wrong interpretation of cardiac silhouette or hilum.

Missing a spinal deformity causing cardiomegaly, or altered silhouette.

Over-relying on patterns without taking into account the sensitivity and specificity of a finding- e.g RA dilatation, type of apex (RV or LV), egg-on-side pattern for TGA.

Misunderstanding PVH for pulmonary plethora can lead to misclassification of the disease.

Wrong reading of hilar shadows is frequent cause of errors.

Many a times, dilated PAs have been interpreted as lymph nodes and patients prescribed antitubercular treatment.

Not paying enough attention to lungs e.g infiltration, or military shadows missed or over-read.

Misinterpretation of normal but infrequent seen structures such as the azygous lobe, diaphragmatic humps, atypical thymus shadow, etc.

TOF with absent pulmonary valve -Dilated main pulmonary artery The pulmonary vasculature is not markedly decreased and may be normal or increased

TOF - markedly decreased lung vasculature and pulmonary bay and right aortic arch

TOF and endocarditis. Note the infiltration in the lungs due to septic emboli from the right-sided vegetations. The boot-shaped heart and decreased pulmonary blood flow is seen

Tricuspid atresia with decreased pulmonary blood flow. LV type of apex. note the left SVC.

Corrected transposition of great vessels. Note the mesocardia, and shadow of L-posed aorta. Pulmonary artery shadow is not distinctly seen and is behind the aortic shadow.

Note the figure-of-8 shadow and increased pulmonary blood flow from supracardiac TAPVC that is not obstructed (A thymic shadow can sometime mimic this, but then the pulmonary blood flow will be normal)

Typical sail-like thymic shadow in a normal infant

Truncus arteriosus. Note cardiomegaly and increased pulmonary blood flow. The main pulmonary artery is not in normal place. Rt PA origin seems high. A right arch would have made the diagnosis easy but is not present

Two examples of transposition with intect septum. Note the variation in TGA X-rays.

Marked cardiomegaly in newborn has few differential diagnoses, Ebstein’s anomaly in this case

Regression of pulmonary artery (PA) pressure and its importance in neonate.

Diffuse cardiomegaly and overpenetrated film. No comments possible regarding lung vasculature

Hyperinflated lung in double aortic arch

TOF and cardiomegaly due to severe anemia. Cardiomegaly does not occur in all lesions of “TOF physiology” unless complicated by other things

Typical ground-glass appearance in a neonate from obstructed infracardiac TAPVC. The angiogram shows the descending vertical vein going below the diaphragm

Increased vasculature in VSDPAH, peripheral pruning, dilated right descending PA, and prominent main PA.

Eisenmenger’s syndrome due to ASD, VSD, and PDA . Note the massive dilatation of pulmonary arteries, cardiomegaly and small aorta shadow in ASD. The PDA Eisenmenger (right) is remarkable for prominent aorticopulmonary shadow. Sometimes a ductal calcification may be seen in the area between aorta and dilated PA. Eisenmenger VSD (middle) shows PAH but neither cardiomegaly nor prominent aorta

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