Download MBBS Chest Xrays Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Chest Xrays 1st Year Handwritten Notes, 2nd Year Handwritten Notes, 3rd Year Handwritten Notes & Final Year Handwritten Notes (Lecture Notes)

Different tissues in our body absorb X-rays at different extents:
Air fat soft tissue bone metal
Least opaque to
most opaque
Most lucent to
least lucent
Black to

Relative Densities
The images seen on a chest radiograph result from the differences in
densities of the materials in the body.
The hierarchy of relative densities from least dense (dark on the radiograph)
to most dense (light on the radiograph) include:
? Gas (air in the lungs)
? Fat (fat layer in soft tissue)
? Water (same density as heart and blood vessels)
? Bone (the most dense of the tissues)
? Metal (foreign bodies)

Four major view of chest radiograph
Postero-anterior (PA)
Antero-posterior (AP)
Lateral view
Other- Apical lordotic view

Postero-anterior position (PA View)
? The standard position for obtaining a routine chest radiograph.
? Patient stands upright with anterior wall of the chest placed against
the film
? The shoulders are rotated forward enough to touch the film, ensuring
that the scapulae does not obscure a portion of the lung fields.
? Usually taken with the patient in full inspiration.
? The PA film is viewed as the patient is standing in front of you.
? Patient and X-Ray tube distance is 6 ft (180 cm).

PA View

Antero-posterior (AP View)
? Used when patient is debilitated, immobilized or unable to cooperate
with the PA procedure.
? Film is placed behind the patient's back with the patient in a supine
? Heart is at greater distance from the film hence appear more
magnified than in the PA.
? The scapulae are visible because they are not rotated out of the view
as they are in a PA.

AP View

Lateral view
? Patient stands upright with the left/right side of the chest against the
film and arm raised over the head.
? Allow the viewer to see behind the heart and diaphragmatic dome.
? Typically used in conjunction with PA view of the same side of chest
to help determine the three dimensional position of organs or
abnormal densities.

Lateral View

Lateral decubitus
? The patient lies on either left or right side than in the standing
position as with the regular lateral radiograph.
? Often used to differentiate between loculated and non loculated
pleural effusion, since the non loculated effusion will collect in the
dependent position

Apical Lordotic View
? Used to observe pathology of apex that not clearly visible in PA
? In this view X-Ray beam is angled towards the head.

Apical Lordotic View

? Three Main Factors Determine the Technical Quality
of the Radiograph
? Inspiration
? Penetration
? Rotation

On a properly exposed chest radiograph:
? The lower thoracic vertebrae should be visible through the heart
? The bronchovascular structures behind the heart (trachea, aortic
arch, pulmonary arteries, etc.) should be seen

In an underexposed chest radiograph,
* The cardiac shadow is opaque,
* With little or no visibility of the thoracic vertebrae.
* The lungs may appear much denser and
whiter, much as
they might appear as with infiltrates present.

With greater exposure of the chest radiograph, the
*Heart becomes more radiolucent and
*Lungs become proportionately darker.
In an overexposed chest radiograph, the air-filled lung periphery
becomes extremely radiolucent, and often gives the appearance of
lacking lung tissue, as would be seen in a condition such as


Patient rotation can be assessed by observing the
clavicular heads and determining whether they are equal
distance from the spinous processes of the thoracic
vertebral bodies.


Carinal angle

B- Bone and soft tissues
? Look at each rib in turn
? Clavicles
? Scapula and humerus if visible
? Lower cervical and thoracic spine

? Two third of the heart lie on the left with one third on the right.
? The heart should take less than half of the thoracic cavity.
? Left atrium, left ventricle create left heart border.
? Right heart border is entirely created by right atrium

Cardiothoracic ratio
CT ratio= CR+CL/T
CR+CL= Transverse Cardiac Diameter
T= Transverse Thoracic Diameter

CTR is more than 50% but heart is normal
Spurious causes of cardiac enlargement
? Portable AP films
? Obesity
? Pregnant
? Ascites
? Straight back syndrome
? Pectus excavatum

RV Hypertrophy
LV Hypertrophy

Both diaphragm should form sharp margin with lateral chest wall
Both diaphragm contour should be clearly visible medially to the spine


Giant Emphysematous bulla


? Air in pleural cavity
? Lung margin visible
? Bilateral fluid level: Any
time you see a
horizontal fluid level, it
means that there is air
and fluid in the pleural

F- Lung fields
? Normally there is a visible markings throughout the lungs due to the
pulmonary artery and veins, continuing all the way to the chest wall.
? Both lungs should be scanned, starting at the apices and working
downwards, comparing the left and right lung fields at the same level.

Lung fields

Pulmonary Embolism
Hampton's sign
Westermark sign
Fleischner sign

Pulmonary Edema
Pulmonary Edema
Acute Diffuse Alveolar
? Bilateral
? Diffuse
? Butterfly pattern
? Soft fluffy lesions
? Coalescing
? Air bronchogram

Miliary tuberculosis

Pancoast Tumour
? Right apical mass
? Cavitating mass
? Para tracheal nodes
? 2nd rib destruction
? Calcified nodes

? Granulomatous
? Bilateral & symmetrical
hilar & mediastinal
? Generalized fibrosis

Lung Mass
? Round or oval
? Sharp margin
? Homogenous

Lung Abscess
? Bilateral
? Multiple
? Fluid level

? Hyperinflation
? Hyperlucency
? Low set flat diaphragm
? Vertical heart
? Pre and infra cardiac lungs
? Barrel shape


Trachea shifted left,
indicating volume loss

Opacified left hemithorax
Entire mediastinum
shifted left, indicating
volume loss


? Lobar or Segmental Density
? Air Bronchogram
? No Loss of Lung Volume

? Density in left lower lung
? Loss of left heart silhouette
? Diaphragmatic silhouette
? No shift of mediastinum
? Blunting of costophrenic

? Density in right upper lung
? Lobar density
? Loss of ascending aorta
? No shift of mediastinum
? Transverse fissure not
significantly shifted
? Air bronchogram

? loss of air in the alveoli; alveoli devoid of air
? Increased density, Signs indicating loss of lung volume
? Types of Atelectesis:
Resorptive Atelectasis
Relaxation Atelectesis
Adhesive Atelectesis
Cicatricial Atelectesis
Round Atelectesis

Signs of Atelectesis
? Shift of mediastinum
? Elevation of diaphragm
? Drooping of shoulder.
? Crowding of ribs
? Movement of Fissures
? movement of oblique fissures.
? Forward movement - LUL atelectasis.
? Backward movement - lower lobe atelectasis.
? Movement of transverse fissure on PA film.
? Movement of Hilum

Compensatory Hyperinflation
Alterations in Proportion of Left and Right Lung
Hemithorax Asymmetry

Atelectesis Right Lung
? Homogenous density right
? Mediastinal shift to right
? Right hemithorax smaller
? Right heart and
diaphragmatic silhouette
are not identifiable

Left Lower Lobe Atelectesis
? Inhomogeneous
cardiac density
? Left hilum pulled down
? Non-visualization of
left diaphragm
? Triangular retrocardiac
atelectatic LLL

? Diffuse haziness
? Apical cap thickening
? Blunting of costophrenic angle
? No shift of fluid in lateral decubitus
? Loss of lung volume
? Lines not corresponding to fissures

Pleural Fibrosis
? Small right hemithorax
? Diffuse haziness
? Tracheal shift to right
? Blunted costophrenic angle
? Lines not corresponding to

Application of knowledge

Coin lesion <3 cm
? Carcinoma/Congenital
? Hamartoma/Hematoma
? AVM/Abscess
? Neoplasm?metastasis
? Granuoma
? TB pneumonia

Multiple Nodules or Mass >3 cm
? Metastasis/Carcinoma/Lymphoma
? TB/granuloma
? Wegener's granulomatosis
? Rheumatoid nodules/Round pneumonia
? Fungal
? Sarcoid
? Septic pulmonary emboli

? Carcinoma-SCC
? Abscess-fungal/bacterial/TB
? Vascular-septic emboli
? Inflammatory-rheumatoid nodule
? Trauma-resolving contusion
? Young-bronchogenic cyst

Unilateral Hyperlucent Lung
? Poland syndrome/Pneumothorax
? Oligemia/Obstruction (PE)
? Emphysema
? Mastectomy
? Swyer James syndrome

Opacified Hemithorax
? Atelectasis
? Pleural effusion
? Pneumonia
? Post-pneumonectomy/ agenesis

Large Cavitary Lung Lesions
? Abscess
? Carcinoma
? TB

Upper Lobe Disease
? Secondary tuberculosis
? Silicosis
? Eosinophilic granuloma

Cavitatory Pneumonia
? Staph
? Strep
? TB
? Gram negative (Klebsiella)

Hilar Adenopathy
? Sarcoidosis
? TB
? Lymphoma
? Bronchogenic ca
? Metastasis

Cavities Containing Masses
? Aspergillosis
? Cavitating bronchogenic carcinoma
? Tuberculosis
? Hydatid cyst

Take home message
? Look carefully for patient identification details and technical issues.
? Be systematic in approach.
? Compare with old films and lateral films.
? It's a chest x-ray, not a lung x-ray.

Thank You

This post was last modified on 24 July 2021