Normal chest xray

normal chest xray radiology

1. NORMAL CHEST XRAY BY DR.PRABHA JOSEPH

2. CONTENTS RECOMMENTED PROJECTIONS Position & centering Penetration Rotation MEDIASTINUM Junctional lines

3. Lungs Hidden areas Diaphragm Soft tissues bones

4. RECOMMENDED PROJECTIONS BASIC POSTERO-ANTERIOR(ERECT) ALTERNATIVE ANTERO-POSTERIOR(ERECT) ANTERO-POSTERIOR(SUPINE) ANTERO-POSTERIOR(SEMI ERECT) SUPPLEMENTAR LATERAL POSTERO-ANTERIOR(EXPIRATION) APICES LATERAL-UPPER ANTERIOR REGION DECUBITUS WITH HORIZONTAL BEAM TOMOGRAPHY

5. POSITIONING: A 35 x 45 cm cassette is selected Patient positioned facing the cassette, with chin extended and centered to the middle of the top of the cassette Feet paced slightly apart so patient remains steady

6. Dorsal aspect of hand placed behind and below the hip with elbows brought forward or by allowing the arms to encircle the cassette therby shoulders are rotated forward pressed downward in contact with the cassete

7. DIRECTION AND CENTERING: Horizontal central beam at right angles to the cassette at the level of 8 th thoracic vertebrae(spinous process of T7) Surface marking of T7 is inferior angle of scapula Exposure is made in full normal arrested inspiration

8. ESSENTIAL IMAGE CHARECTERISTICS: Full lung field with scapula projecting laterally away from lung field Clavicles symmetrical and equidistant from spinous process and not obscuring the lung apices Well inflated( ie anterior six and posterior 10 ribs)

9. Costophrenic angles and diaphragm outlined clearly The mediastinum and heart central and sharply defined Fine demarcation of the lung tissues from hilum to periphery

10. Xray taken in full expiration to confirm the presence of pneumothorax(increasing intrapleural pressure results in compression of lung making pneumothorax bigger) EXPIRATORY TECHNIQUE

11. ANTERO-POSTERIOR(ERECT) Patient standing or sitting with back to cassette, upper edge of the cassette above lung apices Median sagittal plane right angle to the middle of cassette Shoulders bought downward and foreward by hands below hip anf elbows forward

12. CENTERING Horizontal ray, right angle to cassette towards sternal notch Exposure taken in full inspiration

13. ANTEROPOSTERIOR(SUPINE) Patient in supine,cassette placed under patients chest with upper edge of cassette above lung apices Median sagittal plane –right angle to cassette

14. Arms rotated laterally and supported by the side Head supported on pillow &chin raised CENTERING: Right angled towards sternal notch

15. ANTERO POSTERIOR(SEMI ERECT) Patient in semi recumbent position facing xray tube Cassette supported against the back with upper edge above apices Cassette should be parallel to coronal plane

16. Median sagittal plane right angle and to midline of the cassette Arms are rotated medially with shoulders brought forward to bring scapula clear to lung fields CENTERING: Towards the sternal notch

17. LATERAL VIEW Patient to be turned to bring side of investigation in contact with the cassette Median sagittal plane is parallel to the cassette Arms are folded over the head or raised above the head

18. Mid axillary line coincident with middle of the film Cassette is adjusted to include apices and lower lobes to the level of 1 st lumbar vertebrae

19. CENTERING Horizontal ray at right angle to the middle of the cassette at the mid axillary line

20. APICES: POSITION & CENTERING: Patient in PA projection, central ray angled at 30 degree caudally towards C7 spinous process coincident with sternal angle Patient in AP projection ray angled 30 degree cephalad towards sternal angle

21. Patient reclining , and the coronal palne at 30 degree to cassette.nape of neck rests against upper border of cassette,ray directed towars sternal angle

22. UPPER ANTERIOR REGION-LATERAL POSITION & CENTERING: Patient positioned with median sagittal palne parallel to the cassette Centred at the level of shoulder of the side under examination Shoulders drawn backward and arms extended to move the shoulders clear of retrosternal space

23. LORDOTIC Used to demonstrate right middle lobe collapse or interlobar pleural effusion Patient in PA projection,clasping the sides of vertical bucky patient bends backwards at the waist(30-40 degree)

24. PENETRATION: Vertebral bodies and disc spaces just visible down to T8/9 level through cardiac shadow Overpenetration / underpenetration

25. Lungs appear more darker Intervertebral dics spaces are clearly seen OVERPENETRATION

26. UNDERPENETRATED Cardiac shadow is opaque with no visibility of thoracic vertebra

27. ROTATION Medial ends of clavicle equidistand from spinous process

28. Narrowing, displacement, intraluminal lesions Midline in its upper part,then deviates lightly to right around aortic knuckle Normal coronal diameter : 25mm ( males) 21mm(females ) Carina-normal angle is 60-70 degree TRACHEA

29. The right tracheal margin where trachea is in contact with lung,Can be traced from clavicles down to right main bronchus Normal 5mm RIGHT PARATRACHEAL STRIPE :

30. Widening occurs in : Mediastinal lymphadenopathy Tracheal malignancy Mediastinal tumours Mediastinitis Pleural effusion

31. Azygos vein : Lies in the angle between right main bronchus & trachea Should be less than 10mm Enlarged in : Enlarged subcarinal nodes Pregnancy Portal hypertension IVC, SVC obstruction Right heart failure Constrictive pericarditis

32. MEDIASTINUM & HEART 2/3 rd of cardiac shadow lies to left anf 1/3 rd lies to right CARDIOTHORACIC RATIO: Maximum tansverse diameter of the heart and maximum width of thorax at CP angle, measured from inner edge of ribs

33. CRT=( a+b )/c A-Right heart border to midline B-left heart border to midline C-max thoracic diameter above CP angle from inner border of rib normal less than 50%(PA) 60%(AP)

34. All borders are clearly defined except where the heart sits on the left hemidiaphragm . Right Sup. Mediastinal shadow – SVC & innominate vessels, dilated aorta Left sup. Mediastinal shadow – subclavian artery above aortic knuckle

35. ANTERIOR JUNCTION LINE Formed by lungs meeting anterior to ascending aorta 1mm thick Overlying tracheal translucency Runs down from below suprasternal notch slightly curving from right to left JUNCTION LINES

36. Where the lungs meet posteriorly behind the esophagus Straight/curved line convex to the left 2mm wide Extends from lung apices to the aortic knuckle or below POSTERIOR JUNCTION LINE

37. Inverted hockey stick shape From diaphragm on left of midline up & to the right extending to tracheobronchial angle where the azygos V drains into IVC. AZYGO-OESOPHAGEAL INTERFACE

38. Formed by lung & right wall of esophagus From lung apex to azygos Only visualised if esophagus contain air. PLEURO-OESOPHAGEAL STRIPE

39. Adjacent to vertebral bodies Left : <10mm wide( due to descending thoracic aorta) Right : < 3mm Enlargement occurs in tortuous aorta, osteophytes, [paravertebral hematoma ,etc. PARASPINAL LINE

40. Seen in babies & young children Triangular Sail shaped structure Well defined borders projecting from one or both sides of mediastinum THYMUS

41. Borders may be wavy in outline – Wave sign of mulvey – due to indentation by costal cartilages THYMIC SIGNS

42. THYMIC SNAIL SIGN Triangular shaped inferior margin of normal thymus More commonly seen on right

43. THYMIC NOTCH SIGN The inferior border of the thymus blends with the border of cardiac silhouette

44. LUNGS DIVIDED INTO UPPER MID LOWER

45. FISSURES MAIN FISSURES Separates lobes of lung;Usually incomplete allowing collateral air drift to occur between adjacent lobes Visualized when the xray is tangential

46. From the hilum to the 6 th rib in the axillary line Straight / slight downward curve HORIZONTAL/MINOR FISSURE:

47. Both commence posteriorly at T4/5 level passing through hilum Left is steeper finishes 5cm behind anterior costophrenic angle Right ends just behind the angle OBLIQUE FISSURE

48. Comma shaped with triangular base peripherally Always Right sided Forms in apex of lung Consists of paired folds of parietal & visceral pleura, azygos Vein which failed to migrate ACCESSORY FISSURES AZYGOES FISSURE:

49. When left sided contains an accessory hemiazygos Vein

50. Separates apical from basal segments of lower lobes Common on right side Resembles horizontal fissure on PA film Differentiated on lateral film as it runs posteriorly from hilum SUPERIOR ACCESSORY FISSURE

51. As an oblique line running cranially from cardiophrenic angle to hilum Separates medial basal from other basal segments Common on right side INFERIOR ACCESSORY FISSURE

52. Separates lingula from other upper lobe segments Rare LEFT SIDED HORIZONTAL FISSURE

53. INFERIOR PULMONARY LIGAMENT Double layer of pleura extending caudally from lower margin of inferior pulmonary vein in hilum which may or may not attached to diaphragm and attaches lower lobe to mediastinum Frequently seen in CT

54. HIDDEN AREAS THE APICES MEDIASTINUM AND HILA DIAPHRAGM BONES

55. HILA Left hilum higher than right Clearly defined concave lateral borders Similar size

56. Pulmonary artery contribute significantly to the hilar shadow Left Pulmonary Artery lies above the left main bronchus Right Pulmonary artery is anterior to the bronchus resulting in right hilum being lower Normal lymph nodes not seen

57. DIAPHRAGM 2-3mm thick Right higher than left Due to heart depressing left side & not due to liver pushing up the right side Left is higher if stomach or splenic flexure is distended with gas Difference >3cm is significant

58. On inspiration domes are at level of 6 th rib anteriorly & at or below 10 th rib posteriorly Upper borders clearly visualized except on left side where heart is in contact & in cardiophrenic angles when there are prominent fat pads Loss of outline – indicates adjacent lung tissue does not contain air. eg : consolidation or pleural disease

59. Are acute & well defined Obliterated when diaphragms are flat Frequently contain low density ill defined opacity caused by fat pads. COSTOPHRENIC ANGLE

60. SOFT TISSUES Include Chest wall, shoulders & lower neck Breast shadows Skin folds – seen in old age & in babies

61. BONES Sternum Clavicles Scapulae

62. Ribs: Pathological rib notching seen in aortic coartation Central homogenous coastal cartilage calcification in females,curvilinear marginal calcification in males Spine

63. LATERAL VIEW The clear spaces-Retrosternal and Retrocardiac Obliteration of retrosternal space : in thymoma , aneurysms of aorta, nodal masses Widening : emphysema

64. VERTEBRAL TRANSLUCENCY: Vertebral bodies more translucent caudally Loss of this is seen in Posterior basal consolidation

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