This document provides an overview of how to interpret chest x-rays. It discusses the relative densities of different tissues seen on chest x-rays. It then describes the general principles and systematic approach for analyzing chest x-rays, including assessing patient details, x-ray views, inspiration vs expiration, exposure, rotation and angulation. It provides details on common chest x-ray views and anatomical landmarks. It then outlines an ABCDEFGH approach for analyzing different areas of the chest x-ray, including the airways, bones, cardiac shadow, diaphragm, effusions, lung fields, gastric bubble and hila/mediastinum. It describes how to evaluate for various common lung abnormalities.

1. B Y,
D R . S A I L I K I T H A K
H O U S E S U R G E O N
B A N G A L O R E M E D I C A L C O L L E G E A N D R E S E A R C H I N S T I T U T E
M O D E R AT O R ,
D R . J AV E R I YA
A S S I S TA N T P R O F E S S O R
D E P T O F P U L M O N A R Y M E D I C I N E
B A N G A L O R E M E D I C A L C O L L E G E A N D R E S E A R C H I N S T I T U T E
CHEST X RAYS

2. RELATIVE DENSITIES
 Hierarchy of relative densities from LEAST dense to MOST dense :
 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,
therefore appearing most opaque)
 Metal (foreign bodies)
Air
Water
Bone

3. GENERAL PRINCIPLES & APPROACH
GENERAL PRINCIPLES:
 Use a SYSTEMATIC APPROACH to interpret X Rays
 Interpret the CXR in conjunction with the clinical findings
 Always COMPARE with previous CXR if available to assess for change
APPROACH
 Patient Identification Details
 X Ray View
 Breath : Inspiration or Expiration
 Exposure
 Rotation
 Angulation

4. VIEWS
 Postero-anterior view (PA)
 Antero-posterior view (AP)
 Lateral view
 Lateral Decubitus view
 Lordotic view
 Oblique view

5. VIEWS
PA VIEW
AP VIEW

6. PA vs AP VIEW
PA VIEW AP VIEW
CLAVICLE Seen over the lung fields Seen above the apex of the lung
field
SCAPULA-MEDIAL BORDER Seen away from the lung fields Seen over the lung fields
RIBS Posterior ribs better visible Anterior ribs better visible
CARDIA Apparent cardiomegaly

7. LATERAL VIEW

8. LATERAL DECUBITUS VIEW

9. OBLIQUE LORDOTIC
OTHER VIEWS

10. Inspiration | Expiration
Good Inspiration-
• 6 anterior ribs visible
• 10 posterior ribs visible
Eg :In Pneumothorax, expiratory
film is obtained.

11. PENETRATION
UNDEREXPOSURE OVEREXPOSURE
OPAQUE CARDIAC
SHADOW
THORACIC VERTEBRAE
NOT VISIBLE
LUNGS DENSER
LIKE INFILTRATES
CARDIA RADIOLUCENT
THORACIC
VERTEBRAE VISIBLE
UNDEREXPOSED OVEREXPOSED
Intervertebral spaces not visible Intervertebral spaces clearly visible

12. ROTATION

13. ANGULATION
medial ends of the clavicles
should be projected over the
posterior 3rd or 4th ribs
LORDOTIC VIEW

14. A NORMAL CXR PA VIEW

15. APPROACH
 ABCDEFGH APPROACH
 Airways
 Bones & Soft tissue
 Cardiac shadow
 Diaphragm
 Effusion(Pleura)
 Fields(Lung)
 Gastric Bubble
 Hila & Mediastinum

16. AIRWAYS
Normal CXR
Normal Angle : 50-100
Widening of sub-carinal angle :
-Sub-carinal masses –
enlarged lymph nodes, tumors
-Left Atrial Enlargement
-Generalised Cardiomegaly
-Pericardial effusion
LA Enlargement
Double density sign

17. Tension Pneumothorax Atelectasis
TRACHEAL DEVIATION

18. INHALED FOREIGN BODY
Affected side(Right) more
inflated and radiolucent
compared to normal side. In expiration, normal lung will shrink and
become
more dense whereas abnormal areas stay
hyperinflated and lucent
Collapse of left lung due to inhaled foreign body

19. BONES
PECTUS EXCAVATUM
 B/L CERVICAL RIB
SCOLIOSIS
RIB FRACTURE

20. SOFT TISSUE
Areas:
 Supraclavicular fossae
 Axillae
 Breast Shadows
 Tissues along the sides of the breast
 Under the diaphragm
L Mastectomy
Supclavicular masses
(enlarged nodes)
Axillary masses
Lateral chest wall
(surgical emphysema)
Look for:
Breast shadow
NIPPLE SHADOW

21. CARDIA

22. CARDIO-THORACIC RATIO

23. 1)RVH 2)LVH
CARDIAC PATHOLOGIES

24. PERICARDIAL EFFUSION
• Water bottle
configuration
• Increased
Cardiothoracic Ratio

25. PULMONARY ARTERIAL HYPERTENSION
-There is massive enlargement of the pulmonary trunk and
the right and left main pulmonary arteries.

27. EFFUSIONS
 Meniscus sign
PSEUDOTUMOR
Subpulmonic
effusion Hydropneumothorax

28. PNEUMOTHORAX
 Expiratory CXR
Pneumothorax due
to malpositioned NGT

29. LUNG FIELDS
-For the purpose of description
the lungs are divided into zones:
upper, middle and lower.
-Each of these zones occupy
approx. 1/3RD of the height of the lungs.
-The lung zones do not equate to the lung lobes.
-Each zone is compared with its opposite side.

30. LOBAR ANATOMY

32. SILHOUETTE SIGN
 An intrathoracic lesion touching the border of the heart,aorta or diaphragm will
obliterate that border.
 An intrathoracic lesion not anatomically contiguous with a border of one of these
structures will not obliterate that border.

33.  Sites of silhouette sign on the PA
chest radiograph include 3
 right paratracheal stripe: right upper
lobe
 right heart border: right middle lobe or
medial right lower lobe
 right hemidiaphragm: right lower lobe
 aortic knuckle: left upper lobe
 left heart border: lingular segments of
the left upper lobe
 left hemidiaphragm or descending
aorta: left lower lobe
 Sites of silhouette sign on the
lateral chest radiograph include 3:
 posterior border of the heart +/-
posterior left hemidiaphragm: left
lower lobe
 anterior right hemidiaphragm: right
middle lobe
 posterior right hemidiaphragm: right
lower lobe
RML Pneumonia

34. CONSOLIDATION

35. LOBAR CONSOLIDATION
Air bronchogram
RUL and L Lingular
consolidation
RUL consolidation
RML Consolidation RLL Consolidation

36. DIFFUSE CONSOLIDATION
CCF
Bronchopneumonia
BAC

37. MULTIPLE ILL DEFINED

38.  FIBROSIS
 COLLAPSE

39. LUNG MASS
A pulmonary mass appears as an opacity >3cm in diameter,
Malignant lesions-SCC,small
cell Ca,AdenoCa,
Sarcoma,Pulmonary
lymphoma,Metastatic lung
lesions
Inefctions and infestations-
Pneumonia,Lung
Abcesses,Hydatid
cyst,Aspergilloma
Congenital-AV
Malformations,Bronchogenic
cyst
Other-Pumonary infart,Lung
contusion or hematoma,Roung
Atelectasis

40. PULMONARY NODULES
 Nodules are rounded opacities of <3cm.
Macronodular
opacities
Nodules>
5mm in
diameter
Small nodular
opacities
Nodules 2-5mm
Micronodular
opacities/Miliar
y
Nodules 0.5-
1mm
Pulmonary Mets
CAUSES OF
MACRONODULAR
NODULES:
Metastases-Metastases
arising in the
breast,lung,kidney etc
Infections-
TB,Abscesses
Collagen Vascular
diseases-RA,Wegener
Granulomatosis
Pneumoconiosis-
Silicosis

41. MICRONODULAR OPACITIES

42. CAVITY
A cavitation in the lung
is an area of
transradiancy
surrounded by
opacification or wall.
They are usually
associated with a
nodule,mass or area of
consolidation.

43. LUNG ABSCESS
Lung abcsess is the most
common cause of
cavitation with air-fluid
level.
Other causes are :
Malignancy
Tb cavities from rupture
of Rasmussen's
aneurysm.

44. TB

45. TB

46. HYPERINFALTION OF LUNG

47. PULMONARY EDEMA

48.  RADIO-OPAQUE
 Pleural effusion
 Consolidation
 Collapse
 Fibrosis
 Lung Mass
 Pulmonary Edema
 Miliary lesion
 Hilar Lymphadenopathy
 RADIO-LUCENT
 Pneumothorax
 Hydropneumothorax
 Cavity
 Emphysema

49. HILA
U/L
Normal CXR

50. MEDIASTINUM

51. WIDENINGMASS IN
M MEDIASTINUM

52. Medical devices in Thorax
NGT ENDOTRACHEAL TUBE
ICC
PROSTHETIC HEART VALVES
PACEMAKER
R IJV CATHETER

53. THANK YOU