Chest X-Ray Interpretation for the Internist

1. Chest X-Ray Interpretation for the Internist Theresa Cuoco, MD August 2, 2012

2. Disclaimer: I am NOT a radiologist!

3. Why do we need to know? • To direct care while awaiting an “official read” • Low level radiation for the patient • Easily available and noninvasive • Relatively inexpensive

4. Objectives • Basics of technique • Initial basics and type of film • Identification of structures on a “normal” CXR • Alveolar vs interstitial, lobar anatomy, silhouette sign, air bronchograms, and patterns of lung disease • The mediastinum, pleura, and heart

5. The Basics (“the TIONS”) • IdentificaTION • InspiraTION • PenetraTION • RotaTION

6. Inspiration vs. Expiration Indications for an expiratory film? -To detect pneumothorax or look for air trapping (would remain inflated and black instead of white)

7. Penetration A B • Heavy light exposure causes the film to be black (A) • Little light exposure causes the film to be white (B)

8. Rotation

9. Technique • PA and lateral • AP • Which is preferred and why? • Less magnification, sharper images • Better inspiratory effort, pleural fluid and air easier to see • Lateral film – left side of chest against x-ray cassette • Decubitus films

10. Which is which? Crisp CPA More magnification, dull images, poor inspiratory effort

11. Normal Anatomy CPA Left diaphragm Heart Aortic knob Trachea F. Hilum G. Carina H. Stomach bubble J. Ascending aorta

12. The Normal Chest X-Ray Gas in splenic flexure B. CPA C. Heart D. Descending aorta E. Trachea F. Carina G. Hilum H. Aortic knob J. Ascending aorta K. Right diaphragm The left hilum is slightly higher than the right – this is normal

13. Alveolar vs. Interstitial • Alveolar = air sacs • Radiolucent • Can contain blood, mucous, tumor, or edema (“airless lung”) • Interstitial = vessels, lymphatics, bronchi, and connective tissue • Radiodense • Interstitial disease: prominent lung markings with aerated lungs

14. Lobar Anatomy Right: Upper, middle, lower Left: Upper and lower Posterior Anterior The fissure has to be parallel to the x ray beam for it to be seen on the film. The oblique (major) fissures are not visible on the normal frontal projection

15. Lobar Anatomy – Lateral Views Right Left

16. The Silhouette Sign • There are 4 basic radiographic densities • Gas, fat, soft tissue (water), and metal (bone) • Anatomic structures are recognized on x-ray by their density differences • Two substances of the same density in direct contact can’t be differentiated • Loss of the normal radiologic silhouette (contour) is called the “silhouette sign”

17. Localizing Lesions • Where is the silhouette sign? • Obscured right heart border • Right middle lobe infiltrate

18. Localizing Lesions You can still see right heart border

19. Localizing Lesions A: lost heart border = lingular B: lost hemidiaphragm = LLL

20. Localizing Lesions A: loss of right hilum; ascending aorta B: lost aortic knob

21. Localizing Lesions: Review • Ascending aorta, upper R heart border = RUL • R heart border = RML • R anterior hemidiaphragm = RLL • Aortic knob = LUL • L heart border = lingula • L anterior hemidiaphragm or descending aorta = LLL

22. The Air Bronchogram • When lung is consolidated and bronchi contain air, the dense lung delineates the air-filled bronchi • Visualization of air in the intrapulmonary bronchi is called the “air bronchogram sign” • Abnormal finding • Can be seen in: • PNA, edema, infarction • Chronic lung lesions

23. NO Air Bronchograms… • In pneumonia if bronchi are filled with secretions • If cancer obstructs a bronchus • Interstitial fibrosis • Asthma/emphysema (hyperinflation)

24. What do you see?

25. Lung and Lobar Collapse • When a whole lung collapses, the trachea deviates TOWARD the side of collapse (due to volume loss) • Left lung consolidated and collapsed

26. Fissures • Formed by 2 visceral pleural layers • Demarcate the boundaries of the lobes • Shift of fissures is best sign of lobar collapse Minor fissure shifts up: RUL collapse Minor fissure shifts down: RML collapse Major fissures shift down: LL collapse

27. Which lobes have collapsed? Minor fissure is elevated – RUL partially collapsed Heart has moved to right and silhouette sign of right diaphragm – indicated RLL collapse

28. Hilar Displacement • The left hilum is normally slightly higher than the right • Hilar depression indicates collapse of lower lobe • Hilar elevation indicates collapse of upper lobe

29. The Mediastinum A. Ascending aorta B. Aortic knob C. Descending aorta D. R heart border E. SVC F. Rtracheal wall G. L heart X. retrosternal clear space Outside mediastinum: L. L pulmonary artery R. R pulmonary artery

30. The Mediastinum • I: Anterior Mediastinum • Heart • Retrosternal clear space • 4 T’s • II: Middle Mediastinum • Esophagus • Arch and descending aorta • Trachea • III: Posterior Mediastinum • Paravertebral area; most masses neurogenic • Lymph nodes in all 3!

31. The Pleura • The posterior costophrenic angle is the deepest and only seen on the lateral film • The lateral film is more sensitive for detection of small pleural effusions • How much fluid can be seen on a radiograph? • Erect PA: 175 mL • Erect lateral: 75 mL • Decubitus: >5 mL • Supine: Several hundred mL

32. What do you see?

33. Pneumothorax Air enters pleural space with each breath but cant escape, increasing intrapleural pressure – increased pressure depresses the diaphragm, collapses the lung, and shifts the mediastinum away Clinical signs: rapid onset respiratory failure, decreased breath sounds, deviated trachea, JVD

34. The Heart • The horizontal width of the heart should be less than ½ the widest internal diameter of the thorax

35. Left and Right Ventricular Enlargement • Left ventricular enlargement • Frontal: LHB moves laterally and cardiac apex inferolaterally • Lateral: LHB moves inferoposteriorly • Right ventricular enlargement • Frontal: RHB further right • Lateral: Contacts lower half of sternum (instead of lower 3rd)

36. Cephalization • Enlargement of the upper lobe vessels • “Vascular redistribution” • “Kerley B” lines: interstitial edema thickening the interlobular septa causing short lines perpendicular to the pleural surface

37. Systematic approach • ABCDE • Airway • Bones and breasts • Cardiac and costophrenic • Diaphragm • Edges and extrathoracic • Fields (lung fields and failure)

38. Cases

43. Young man with cancer

44. Osteosarcoma w Pulmonary Met Metal nipple markers have been placed 1. pulmonary nodule below right nipple marker where ribs cross 2. Right shoulder amputated: pulmonary met from osteosarcoma

45. Young man without symptoms

46. Anterior Mediastinal Mass Strange cardiomediastinal shape on left - causes silhouette of left atrium ,pulmonary artery, and aortic arch Lateral shows density in retrosternal clear space

47. Dyspnea with sudden CP & fever

48. Heart Failure and Perf Ulcer Cephalization, enlarged heart, free air