Presentation is loading. Please wait.

Presentation is loading. Please wait.

Thoracic Radiographic Anatomy Einav Shochat MS4 Visiting Medical Student.

Similar presentations


Presentation on theme: "Thoracic Radiographic Anatomy Einav Shochat MS4 Visiting Medical Student."— Presentation transcript:

1 Thoracic Radiographic Anatomy Einav Shochat MS4 Visiting Medical Student

2 PA and Lateral Chest Radiograph

3 Lobar Anatomy There are three lobes in the right lung and two in the left Lobes are divided into anatomic segments; each is supplied by its own bronchus and blood vessels

4 RUL RML Lobar Anatomy: Right upper & right middle lobes RML borders the right atrium and much of the dome of the diaphragm. Indistinct borders of these areas suggest RML pathology.

5 RLL Lobar Anatomy: Right lower lobe Consolidations of the lower lobes are largely behind the diaphragm dome, hence the diaphragm border will still appear sharp on the PA film.

6 LUL Lobar Anatomy: Left upper lobe LUL borders the left atrium, left ventricle and much of the dome of the diaphragm. Indistinct borders of these areas suggest LUL pathology.

7 LLL Lobar Anatomy: Left lower lobe Most of the LLL is posterior to the left border of the heart and the dome of the diaphragm. Distinct borders of these areas with surrounding opacity is seen with LUL consolidations.

8 Can you find the source of this patient’s fever and cough?

9 Left Lower Lobe pneumonia Note the abnormal opacification of the lower vertebrae in the lateral view. Normally there is less soft tissue around the inferior thoracic vertebrae making them appear darker than the more superior vertebrae. See next slide for comparison. Distinct borders

10 On the right is the same radiograph from the previous slide with a normal one for comparison. Normally, inferior vertebrae appear darker Note the general opacification of the lower lobe in the image on the right. Look particularly at the vertebral bodies and posterior border of the heart.

11 Lobar Anatomy The lobes of the lungs are lined by visceral pleura, which normally is not visualized except along the interlobar fissures Fissure anatomy may have many anatomic variations and may not be complete

12 On the right there are two fissures, the oblique (major) fissure and the horizontal (minor) fissure. The left lung contains an oblique fissure only. minor major minor

13 It is uncommon to see distinct fissures. If opacified there may be thickening of or fluid between the pleura. This patient has congestive heart failure and subsequent subpleural thickening. Can you identify the oblique fissures?

14 It is uncommon to see distinct fissures. If opacified there may be thickening of or fluid between the pleura. This patient has congestive heart failure and subsequent subpleural thickening. Can you identify the oblique fissures?

15 Here there is fluid trapped between the pleura within the fissures.

16 Occasionally accessory fissures can be found. For example, the azygos fissure, a normal variant, can form during the embryonic migration of the azygos vein through the apical pleura.

17 Knowing the normal position of the interlobar fissures helps us diagnose pulmonary volume changes. For example when a lobe collapses the fissure is displaced and seen as a sharp interface between opacified (collapsed) and aerated lung. Can you identify the pleural lining of the collapse lung?

18 scapulae Major fissure not normally seen on the PA film because it runs parallel to the radiation beams Knowing the normal position of the interlobar fissures helps us diagnose pulmonary volume changes. For example when a lobe collapses the fissure is displaced and seen as an interface between two densities (e.g., opacified/collapsed and aerated lung) Can you identify the pleural lining of the collapse lung? Left hemidiaphragm becomes indistinct when adjacent to collapsed LLL Inferior vertebrae opacified by LLL atelectasis Left pulmonary artery: vasculature are pulled inferiorly by the collapsed LLL

19 What’s happened here?

20 Right upper lobe collapse

21 We can use the pleura to identify whether a mass is within the lung parenchyma or in the extrapleural space. Is this mass intrapleural or extrapleural? How can you tell?

22 We can use the pleura to identify whether a mass is within the lung parenchyma or in the extrapleural space. Is this mass intrapleural or extrapleural? How can you tell? Extrapleural The medial border of the mass is draped by pleura and is distinct where it is adjacent to aerated lung. The lateral border is next to bone and soft tissue of more similar density.

23 The pleura is often involved in inflammatory and traumatic insults to the chest. These may result in areas of thickening or distortion of the pleural lining, which may be appreciated in the normally sharp costophrenic & cardiophrenic angles/sulci. Lateral costophrenic angle Posterior costophrenic angle Cardiophrenic angle

24 Pleural effusions can be identified by: blunting of the lateral and posterior costophrenic sulci, a meniscus sign, opacification of a hemithorax, and/or fluid in the fissures. Small free-flowing pleural effusions are best identified on the lateral radiograph as this view captures the most dependent region of the thoracic cavity, the posterior costophrenic angles.

25 Mediastinum Many structures can be identified within the mediastium; we will start with the heart and blood vessels…

26 How many structures can you identify?

27 LV RV SVC Aortic pulmonary recess Left Aortic arch Aorta RA pulmonary artery LA Right pulmonary artery (lower lobe) Vascular pedicle

28 How many structures can you identify?

29 Gastric air bubble Left upper lobe bronchus IVC Right hemidiaphragm LV LA RV Pulmonary outflow tract Aorta Right upper lobe bronchus RPA LPA Confluence of pulmonary veins Brachiocephalic vessels Trachea Left hemidiaphragm Scapula Manubrium Body of sternum Retrosternal space

30 Which valve has been replaced?

31 Aortic valve Note the orientation of the valve perpendicular to the plane of the PA film.

32 Which valve has been replaced?

33 Pulmonic The pulmonary outflow tract is more superior and lateral than many people think.

34 Last one, name the valves…

35 Aortic Tricuspid Mitral Tricuspid Mitral Aortic

36 The Vascular Pedicle Found in the superior mediastinum. Right and left margins are normally formed by the superior vena cava and the descending portion of the aortic arch, respectively. A widened vascular pedicle can have several etiologies including elevated intravascular volume, aortic trauma, or pericardial effusion.

37 Vascular pedicle Aortic arch Superior vena cava

38 Intravascular volume depletion Intravascular volume elevation vs.

39 Vascular pedicle Intravascular volume depletion Intravascular volume elevation Intravascular volume elevation resulting in an expanded SVC should not be mistaken for hematoma, which would have a less distinct border and more opacified appearance. vs. Superior vena cava Aorta Superior vena cava Aorta

40 Trauma patient with an aortic transection Note the vascular pedicle’s “fuzzy”, opacified right border.

41 What is happening here?

42 Looks pretty wide eh? Can you follow the heart borders?

43 What is happening here? The wide vascular pedicle here results from a pericardial effusion The pacemaker wires roughly outline the right atrium border If you look closely you can make out the superior pericardial border The left heart border can be seen within the effusion effusion Comparing this with older films can also help make the diagnosis.

44 Pulmonary Airways & Vasculature The lungs on the normal chest radiograph are made by pulmonary vessels, the bronchi are normally not seen. This is because: Pulmonary vessels are blood-filled with density similar to water. Bronchi are filled with air and normally have thin walls that do not provide contrast to aerated lungs.

45 Pulmonary Airways & Vasculature When lung parenchyma fill with water or inflammatory material: Water-density vessels become less distinct. Air-filled bronchi can be seen as “air bronchograms”. If airways are obstructed (e.g., tumor) they may fill with fluid and no “air bronchograms” will be appreciated.

46 How do these two radiographs differ?

47 Normal well-defined vessels Abnormal indistinct vasculature

48 In the normal chest radiograph only airways within the mediastinum are apparent. Trachea Left mainstem bronchus Trachea Right mainstem bronchus Left mainstem bronchus

49 What is the source of this man’s chronic cough?

50 Right upper lobe collapse secondary to obstruction of the bronchus by squamous cell carcinoma. Unilateral lung opacification with ipsilateral tracheal shift from the pressure differential helps identify RUL collapse Obstruction Horizontal fissure Inferior pulmonary ligament tethering the lobe and tenting the diaphragm Tented right hemidiaphragm RUL

51 What is the source of this patient’s dyspnea?

52 Atelectasis Seen commonly as crowded parallel air-bronchograms (if airways are not obstructed)

53 What is abnormal here?

54 What is abnormal here? The patient has Sarcoidosis. Think about lymphadenopathy when opacities obscure the aortic pulmonary recess (PA) or surrounding the left distal main bronchus (on the lateral) Bronchus lumen is obscured Lateral border of the SVC is obscured by lymphadenopathy

55 Other Mediastinal Structures Esophagus Thyroid Thymus Lymph nodes These are generally not seen unless there is pathology

56 What could be the source of this anterior mediastinal mass?

57 Ddx: Lymphoma/leukemia, germ cell tumors (e.g., teratoma), thymic mass (e.g., thymoma, cyst), enlarged thyroid, vascular (e.g., hematoma, aortic aneurysm). This patient has a thymoma.

58 How about this one?

59 This patient has a an enlarged thyroid gland.

60 Extrapulmonary Structures Diaphragm Stomach/gastric bubble Liver, spleen Bones: clavicles, ribs, scapulae, spine Other soft tissues

61 In the normal radiograph, the diaphragm is domed with the right side higher than the left (i.e., the heart lying on the left side of the diaphragm may contribute to the lower level). Right diaphragm Left diaphragm

62 Elevated intrathoracic pressures (e.g., hyperinflation from obstructive lung disease, tension pneumothorax) will flatten the diaphragm. Flat Flattened

63 Not many structures left, so let’s just quiz…

64 What’s abnormal in these films?

65 The lucent stripe along the inferior heart border, crossing midline is called a “continuous diaphragm” sign and is indicative of pneumomediastinum. Notice the air around the left and right pulmonary arteries. LLL atelectasis

66 What’s abnormal in this film?

67 Normally the only air we see under the diaphragm is in the gastric bubble and bowels. Subdiaphragmatic free air is indicative of perforated viscus. Free air

68 What’s abnormal in this film?

69 Hiatal hernia

70 This hiatal hernia is easier to see with the gastric air bubble behind the heart.

71 What’s abnormal in this film?

72 Gastric bubble, bad sign Ruptured diaphragm Tracheal deviation

73 What’s abnormal in this film?

74 Splenomegaly Gastric air bubble

75 What’s abnormal in this film? Gastric air bubble

76 What’s abnormal in this film? Gastric air bubble Ouch

77 Which patient needs a chest tube? Gastric air bubble

78 Which patient needs a chest tube? Gastric air bubble Skin fold lateral border Pneumothorax Scapula medial border To decide whether a line in the lung represents the scapula, a skin fold or a pneumothorax consider the density difference between the two sides of the line. A pneumothorax will have a sharp line with air density (equal density) on both sides. Skin or scapula will have a line with air on one side and more opaque tissue on the other.

79 What’s abnormal in this film?

80 The patient is rotated slightly causing the “heel effect”, the relative over exposure of one hemithorax compared to the other caused by uneven radiation. Looking at the relative exposure of the extrathoracic soft tissues can help identify the “heel effect”. Nothing The left lung appears more opacified but it is the result of uneven radiation.

81 References: Collins J, Stern EJ. Chest Radiology, the Essentials. Lippincott, Williams & Wilkins. 1999. Dafner RH. Clinical Radiology, the Essentials. 2 nd Ed. Lippincott, Williams & Wilkins. 1999. Freindlich IM, Bragg DG. A Radiologic Approach to Diseases of the Chest. 2 nd Ed. Williams & Wilkins. 1997.


Download ppt "Thoracic Radiographic Anatomy Einav Shochat MS4 Visiting Medical Student."

Similar presentations


Ads by Google