Normal Chest X-Rays & Its Systemic Approach- Anatomy

Basic about CXR and its systemic approach

1. NORMAL CHEST X-RAY Dr. Bijay Kumar Yadav (1 st Year Radiology Resident) I.K KSMA, Bishkek x-ray Tube T able Film cassette

2. Wilhelm Conrad Roentgen - Father of Radiology Nov 8, 1895 – Discovered unknown radiations with photographic effect which he named ‘ axa rays’ He got the Nobel prize in 1901.

3. Common views of the chest X-Ray: PA ( Postero -anterior) view AP (Antero-posterior) view Lateral view Lateral Decubitus Oblique view Apical / Lordotic view Paired Inspiratory - Expiratory view

4. 1. PA VIEW: Most commonly ordered radiological investigation. Posterior-Anterior (PA) is the standard projection PA views are of higher quality and more accurately assess heart size than AP images PA projection may not always be possible

5. PA Projection

6. 2. AP VIEW: Lower quality Heart magnification (farther from film ) Clavicles are projected more cranially above lung apex Scapulae overlie lung fields Ribs appear horizontal Gastric bubble is absent

7. AP Projection

8. AP view CXR

9. PA view v/s AP View IN PA VIEW:- Clavicles don’t project too high into the apices or thrown above the apices (more horizontal) Heart wont be magnified over the mediastinum therefore preventing the appearance of cardiomegaly Scapula are away from the lung fields Ribs are obliquely oriented in PA view Spine and posterior ends of ribs are clearly seen

10. 3. LATERAL VIEW Routinely left lateral film obtained In specific lesion, the side of the interest is positioned adjacent to the film Should be viewed along with the PA film

11. CHEST X-RAY: Systemic Approach Technical Aspects Trachea Mediastinum & Heart Hila Diaphragm CP Angles Lungs: Fields (Zones) Fissures Pulmonary Vessels Bronchial Vessels Hidden Areas Bony Framework Soft Tissues

12. A. Technical Aspects : Patient Name, Date Adequate inspiration Centering & Rotation Exposure\Adequate penetration Motion Side markers

13. a. Inspiration The diaphragm should be found at about the level of 9 - 10 th posterior rib or 5 - 6 th anterior rib on good inspiration Inspiration Expiration Note Changes In Heart Size And Vascularity Due To Expiration .

14. Inspiration - Expiration Films taken after maximal inspiration & expiration Advantage Helps in detection of focal or diffuse air trapping – advantage in suspecting FB & small pneumothorax Demonstration of diaphragmatic movement

15. b. Penetration On a good PA film, the thoracic spine disc spaces should be barely visible through the heart but bony details of the spine are not usually seen. On the other hand penetration is sufficient that bronchovascular structures can usually be seen through the heart. 

16. UNDERPENETRATION : Likelihood of missing an abnormality overlying by another structure OVERPENETRATION : R esults in loss of visibility of low density lesion e.g. Early C onsolidation

17. c. Centering & Rotation Can be assessed by observing the clavicular heads and determining whether they are equal distance from the spinous process of the thoracic vertebral bodies. Good centering: 1/3 of heart is to right & 2/3 to left of midline.

18. c. Motion: Cardiac margin, diaphragm and pulmonary vessels should be sharply marginated in a completely still patient.

19. B . TRACHEA : Should be examined for: Narrowing Displacement Intraluminal lesions Position: Central, slightly deviated towards Right around the aortic knuckle Calibre : Even Max. Coronal: 25mm (M), 21mm (F)

20. Carina angle: 60 - 75 widening

21. C . MEDIASTINUM & HEART : Central dense shadow is formed by: Heart Mediastinum Sternum Spine

22. Cardiac Shadow Good centering: Heart: 2/3 left 1/3 right In chest x-ray heart examined for size, shape, position, silhouette.

23. Size measurement: CT ratio: < 50% Transverse cardiac diameter: < 15.5 cm (M) < 14.5 cm (F) Heart size appears enlarged on expiration, supine film, AP film & when diaphragms are elevated

24. Borders

25. Silhouette sign: The silhouette sign is the absence of depiction of an anatomic soft-tissue border resulting from the juxtaposition of structures of similar radiographic attenuation . Density difference  delineation of the outline. There are four basic densities in x-ray images: Gas Fat Water / soft tissue Bone / calcium Loss of density difference of the adjacent structures  loss of silhouette.

26. D . HILA : Formed by superior pulmonary vein & B asal pulmonary artery (Radiological H ilum) 97% - left hilum is higher (left pulmonary artery is above bronchus) Hila should be of equal density, similar size & clearly defined concave lateral borders

27. Structures in the H ilum Pulmonary arteries & upper lobe veins-significant contribution to hilar shadow Normal LN- Not seen in plain radiography Bronchi- walls seen end on

28. E . DIAPHRAGM : Right higher – Not more than 3 cm. May lie in same level & In small % left higher (~3%)

29. On inspiration – Anterior 6 th rib , Posterior 10 th rib (Erect film) Both domes – gentle curves- steepen towards posterior angles Clearly defined upper borders except area where heart rests & anterior cardio-phrenic angles (fat pad) Loss of outline – adjacent tissue no air-consolidation or pleural effusion Free intra peritoneal gas-under surface of diaphragm: 2-3mm thick

30. Diaphragm (Normal Variants) Diaphragmatic Hump: Rt side anteriorly Eventration : P art of the muscle is absent- Left side Scalopping : Rt side- short curves convex upwards Muscle Slips: Rt side- short curves concave upwards

31. Left v/s Right Dome O f Diaphragm: Anterior left hemidiaphragm is obliterated by the cardiac contact; right is seen in entirity By identifying the fissures: left oblique fissure is contacts diaphragm ~5 cm behind the anterior costophrenic angle On left lateral film, the right anterior and posterior costophrenic sulci should project beyond the corresponding left sided sulci as a result of x-ray beam divergence By seeing air in stomach and splenic flexure below the left hemidiaphragm

32. CP Angles Acute and well defined Obliterated when diaphragms are flat

33. E. LUNGS : Trachea Carina Right and Left Pulmonary Bronchi Secondary Bronchi Tertiary Bronchi Bronchioles Alveolar Duct Alveoli

34. Zones Of Lungs Lower border of 2 nd & 4 th ribs separates the zones zone 1 zone 2 zone 3

35. Lobes Of Lungs Right:- Upper, Middle & Lower Left:- Upper (Includes Lingular segment) & lower

36. RUL 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 4 th right anterior rib

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

38. RLL The 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. Review of the lateral plain film surprisingly shows the superior extent of the RLL.

39. Right Lobe Fissures These 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. T he major fissure oriented obliquely extends posteriorly and superiorly approximately to the level of the 4 th vertebral body.

40. LUL The lobar architecture of the left lung is slightly different than the right. Because there is no defined left minor fissure, there are only two lobes on the left; the left upper

41. LLL Left lower lobes These 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.

42. Fissures Of Lungs Major: Right & Left oblique Fissure Minor : Right Horizontal Fissure

43. Pulmonary Vessels Measure the right descending Pulmonary artery Diameter- ( 16mm in Male & 15mm in Female) Distribution of flow from apex to base At first intercostal space– normal vessels not more than 3 mm in diameter Erect- Lower lobe vessels prominent Supine- Equalize Distribution of flow from central to peripheral -tapering Vascular lung markings- Central 2/3 rd

44. F. HIDDEN AREAS : Apices : P artially obscured by ribs, costal cartilage, clavicles & soft tissues Central lesions obscured by mediastinum and hila Posterior & lateral basal segments of lower lobes & posterior sulcus obscured by the downward curve of the posterior diaphragm Hidden areas due to bones

45. G. BONY STRUCTURES : RIBS SCAPULA CLAVICLES SPINE STERNUM

46. H. SOFT TISSUE : General survey in chest wall, shoulders & lower neck. Breast Shadows Supraclavicular areas Axillae Tissues along sides of Breasts

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