Chest Radiological Anatomy

Introduction in chest radiology

Techniques - Projection•P-A (relation of x-ray beam to patient)

Techniques - Projection (continued)

•Lateral

• Orientation: In this we are making reference to the position of the patient and the xray beam. A PA radiograph is obtained with the x-ray traversing the patient from posterior to anterior and striking the film. Similarly an AP radiograph is positioned with the xray traversing the patient from anterior to posterior striking the film. The cardiac border or silhouette will appear larger on an AP radiograph due to the magnification effect of the more anteriorly located heart relative to the film.

• Typically portable radiographs are obtained AP, as the patient is not able to stand. Standing radiographs in the department are typically obtained PA with a corresponding lateral radiograph. The PA and lateral radiograph best demonstrate the actual cardiac size with minimal magnification compared to the AP exam.

Orientation

PA AP

• Inspiration: The volume of air in the hemithorax will affect the configuration of the heart with question of cardiac enlargement with a shallow level of inspiration. The vascular pattern in the lung fields will be accentuated with a shallow inspiration since the same amount of blood flow is now distributed to a smaller volume of lung.

• The level of inspiration can be estimated by counting ribs. Visualization of nine posterior ribs, or seven anterior ribs on an upright PA radiograph projecting above the diaphragm would indicate a satisfactory inspiration.

Inspiration Expiration

• Penetration: Refers to adequate photons traversing the patient to expose the radiograph. This is often limited in patients of large size such that there is poor visualization of structures in the lower lung fields and in a retro-cardiac location. The lack of penetration renders the area “whiter” than with an adequate film and can simulate pneumonia or effusion. In an ideal radiograph the thoracic spine should be barely perceptual viewing through the cardiac silhouette. The soft tissues at the shoulder can also give an estimate of the relative degree of penetration of the film.

Penetration

• Rotation of the patient distorts mediastinal anatomy and makes assessment of cardiac chambers and the hilar structures especially difficult. Chest wall tissue also contributes to increased density over the lower lobe fields simulating disease. Rotation of the radiograph is assessed by judging the position of the clavicle heads and the thoracic spinous process. Ideally the clavicle heads should be equidistant from the spinous process.

Rotation

Rotation (continued)

Rotation

How to approach an X-ray?

Reading a Chest X-ray

• First thing:– Correctly put of the film

• Then perform your search pattern– which you always follow when looking at any film – this way you will miss fewer findings

Reading a radiograph

• Start reading every radiograph by scanning the areas of least interest first, working your way to the more important areas.

• You will be less likely to miss important secondary findings.

Chest Film Search Patterns

• ABCs– Abdomen– Bone– Chest– Soft tissues

• ATMLL– Abdomen– Thorax– Mediastium– Lung– Lung

These are the two main search patterns that people use when evaluating a chest film.

“ATMLL” Search Pattern

• Remember

• A = Abdomen• T = Thorax• M = Mediastinum• L = Lungs (unilaterally)• L = Lungs (bilaterally)

Searching the “Abdomen”• Scan across the upper abdomen several times

• Evaluate normal gas containing structures:• Stomach• Hepatic flexure of the colon• Splenic flexure of the colon

• Evaluate the liver and on occasion one can visualize the spleen

Structures Visualized: Stomach gas bubble Splenic flexure Liver Hemidiaphragms

Abdomen dz that can mimic Lung disease include: Subphrenic abscess Diaphragmatic hernia Hiatal Hernia

Searching the Bony “Thorax”• Start at the right base, look at the soft tissues of

the chest wall, ribs, spine and shoulder girdle

• Go up one side and come down on opposite side

• Remember:– Posterior ribs descend medial to lateral– Anterior ribs descend lateral to medial

Structures Visualized: Breast Tissue Posterior Ribs Anterior Ribs Scapula Clavicle SpineThorax cage dz that may stimulate chest dz: Bony metastasis Rib / Clavicle fractures

Searching the “Mediastinum”

• An organized search of the mediastinum is complicated because of all the overlapping structures.

• Start with a global look for contour abnormalities, then follow with a more detailed search

Three searches of the mediastinum: 1. Trachea and carina

2. Aorta and the heart

3. Hilum

Three searches of the mediastinum: 1. Trachea and carina

2. Aorta and the heart

3. Hilum

Three searches of the mediastinum: 1. Trachea and carina

2. Aorta and the heart

3. Hilum

Three searches of the mediastinum: 1. Trachea and carina

2. Aorta and the heart

3. Hilum

Searching the “Lungs”

• Since most chest x-rays are ordered to evaluated for lung disease, so the lungs are examined last.

• They are important, so their evaluation should be more through, therefore we evaluate them twice.– Once individually– Second time comparing right and left

Structures Visualized: Costophrenic angles Lung fields Pulmonary vasculature Right minor fissure

Left Lateral Chest Film

• Valuable radiographic study• Helps to better localize lesions• Allows to visualize overlapping tissues• Allows the visualization of hidden

pathology

Searching the Lateral Chest Film

• The pattern is the same:1) Abdomen2) Thoracic cage strutures3) Mediastinum4) Lungs

Search Pattern: Abdomen Thoracic cage and bones Mediastinum Lungs

Search Pattern: Abdomen Thoracic cage and bones Mediastinum Lungs

Search Pattern: Abdomen Thoracic cage and bones Mediastinum Lungs

Search Pattern: Abdomen Thoracic cage and bones Mediastinum Lungs

Search Pattern: Abdomen Thoracic cage and bones Mediastinum Lungs

But before that we need to have a good understanding of Normal Radiographic Anatomy

Let’s look at some of the visual abdominal

structures

Stomach gas bubbleSplenic flexure of the large intestines

Liver

Left Hemidiaphragm

Right Hemidiaphragm

Let’s look at the Bony thorax

RibsSpineClavicleScapulaChest wall

Let’s look at the Bony thorax

RibsSpineSternum

Trachea on CXR

Let’s look at the normal Mediastinal Structures

Hilum

VesselsAortic Arch

Pulmonary Artery

Left Atrium

Left Ventricle

Inferior Vena Cava

Right Atrium

Ascending Aorta

Superior Vena Cava

Descending Aorta

Aortic Knob/Arch

Ascending Aorta

Right Ventricle

Inferior Vena Cava

Left Ventricle

Left Atrium

CT - mediastinum

Imagine toracica normala. (liniile numerotate indica nivelurile la care au fost

facute sectiunile de mai jos)

1. Traheea.

2. Esofag.

3. Muschiul trapez.

4. Clavicula stanga.

4*. Clavicula dreapta.

5. Muschiul subscapular.

6. Muschiul infraspinos.

7. Muschiul supraspinos.

8. Marele pectoral.

9. Micul pectoral.

10. Muschiul dintat anterior.

11. Latissimus dorsi.

12. Muschiul erector spinae.

13. Artera subclavie stanga.

13a. Artera subclavie dreapta.

14. Artera carotida comuna stanga.

14*. Artera carotida comuna dreapta.

15. Vena jugulara interna stanga.

16. Scapula.

17. Coasta I.

18. Manubriul sternal.

21. Vena brahiocefalica dreapta.

26. Vena axilara stanga.

1. Traheea.

2. Esofag.

3. Muschiul trapez

5. Muschi subscapular.

6. Muschi infraspinos.

7. Muschi supraspinos.

8. Marele pectoral.

9. Micul pectoral.

11. Latissimus dorsi.

12. Muschiul erector spinae.

13. 13a. Artere subclavii.

14. 14*. Arterele carotide comune.

16. Scapula.

18. Manubriul sternal.

21. 21*. Vene brahiocefalice.

27. Artera brahiocefalica.

1. Traheea.

2. Esofag.

3. Muschiul trapez.5. Muschi subscapular.

8. Marele pectoral.

11. Latissimus dorsi.

12. Muschiul erector spinae.

13. Artere subclavii.

14. Arterele carotide comune.16. Scapula.18*. Corpul sternului.

21. 21*. Vene brahiocefalice.24. Muschiul rotund mare.

27. Artera brahiocefalica.

1. Traheea.

2. Esofag.

3. Muschiul trapez.

5. Muschiul subscapular.

6. Muschiul infraspinos.

8. Marele pectoral.

11. Latissimus dorsi.

12. Muschiul erector spinae.

13. Arterele subclavii.

14. Arterele carotide comune.

16. Scapula.

18*. Corpul sternului.

19. Arcul aortei.

19*. Aorta ascendenta.

21. 21*. Vene brahiocefalice.

22. Vena cava superioara.

24. Muschiul rotund mare.

25. Muschiul rotund mic.

27. Artera brahiocefalica.

1. Traheea.

2. Esofag.

3. Muschiul trapez.

5. Muschiul subscapular.

6. Muschiul infraspinos.

11. Latissimus dorsi.

12. Muschiul erector spinae.

18*. Corpul sternului.

19. Arcul aortei.

22. Vena cava superioara.

24. Muschiul rotund mare.

25. Muschiul rotund mic.

1. Traheea.

2. Esofag.

3. Muschiul trapez.

5. Muschiul subscapular.

6. Muschiul infraspinos.

10. Muschiul dintat anterior.

11. Latissimus dorsi.

16. Scapula.

18*. Corpul sternului.

19*. Aorta ascendenta.

19+. Aorta descendenta.

20. Vena azygos.

20*. Arcul venei azygos.

22. Vena cava superioara.

24. Muschiul rotund mare.

25. Muschiul rotund mic.

2. Esofag.

3. Muschiul trapez.

6. Muschiul infraspinos.

11. Latissimus dorsi.

12. Muschiul erector spinae.

16. Scapula.

18*. Corpul sternului.

19*. Aorta ascendenta.

19+. Aorta descendenta.

20. Vena azygos.

22. Vena cava superioara.

24. Muschiul rotund mare.

29. Trunchiul pulmonar.

30. Artera pulmonara dreapta.

30* Artera pulmonara stanga.

2. Esofag.

3. Muschiul trapez.

10. Muschiul dintat anterior.

11. Latissimus dorsi.

12. Muschiul erector spinae.

16. Scapula.

18*. Corpul sternului.

19*. Aorta ascendenta.

19+. Aorta descendenta.

20. Vena azygos.

22. Vena cava superioara.

24. Muschiul rotund mare.

29. Trunchiul pulmonar.

30. Artera pulmonara dreapta.

30*. Artera pulmonara stanga.

32. Carina traheala.

2. Esofag.

3. Muschiul trapez.

10. Muschiul dintat anterior.

11. Latissimus dorsi.

16. Scapula.

19*. Aorta ascendenta.

19+. Aorta descendenta.

20. Vena azygos.

22. Vena cava superioara.

29. Trunchiul pulmonar.

30. Artera pulmonara dreapta.

33. Ventriculul drept.

34. Atriul drept.

18*. Corpul sternului.

19*. Aorta ascendenta.

19+. Aorta descendenta.

20. Vena azygos.

33. Ventriculul drept.

34. Atriul drept.

35. Atriul stang.

36. Ventriculul stang.

37. Vena pulmonara dreapta.

37*. Vena pulmonara stanga.

38. Septul interventricular.

18+. Procesul xifoid al sternului.

19+. Aorta descendenta.

20. Vena azygos.

33. Ventriculul drept.

34. Atriul drept.

35. Atriul stang.

36. Ventriculul stang.

37. Vena pulmonara dreapta.

37*. Vena pulmonara stanga.

38. Septul interventricular.

39. Sinusul coronar.

40. Valva tricuspida.

Upper

Middle

Lower

Lung Fields

Let’s look at the normal Lung Structures

Retrosternal Clear Space

Retrocardiac Clear Space

Lateral Costophrenic Sulci (Recesses, Angles)

Cardiophrenic Sulci(Recesses, Angles

Posterior Costophrenic Sulci (Recesses, Angles)

What are the Pulmonary Fissures?

• They are the coming together of the visceral pulmonary pleura.

• Right lung– Oblique (major) fissure– Horizontal (minor) fissure

• Left Lung – Oblique (major) fissure

Horizontal Fissure

Right Oblique Fissure

Left Oblique Fissure

LUL

LLL

RUL

RML

RLL

A closer look at

the fissures

Lobes• Right upper lobe:

Lobes (continued)

• Right middle lobe:

Lobes (continued)

• Right lower lobe:

Lobes (continued)

• Left lower lobe:

Lobes (continued)

• Left upper lobe with Lingula:

Lung segments – right lung

A. Lateral. B. Anterior C. Posterior

I. Lobul superior.

1. Segmentul apical.

2. Segmentul posterior.

3. Segmentul anterior.

II. Lobul mijlociu.

4. Segmentul lateral.

5. Segmentul medial.

III. Lobul inferior.

6. Segmentul apical.

7. Segmentul mediobazal.

8. Segmentul anterobazal.

9. Segmentul laterobazal.

10. Segmentul posterobazal.

D. Medial

E. Basal.

Lung segments – left lung

I. Lobul superior.

1. Segmentul apical.

2. Segmentul posterior.

3. Segmentul anterior.

4. Segmentul lingular superior.

5. Segmentul lingular inferior.

II. Lobul inferior.

6. Segmentul apical.

7. Segmentul mediobazal.

8. Segmentul anterobazal.

9. Segmentul laterobazal.

10. Segmentul posterobazal.

A. Lateral. B. Anterior C. Posterior D. Medial

E. Basal.

CT - pulmonary window

Lobul superior

stang

Traheea

Lobul superior drept

Lobul inferior stang

Bronhia principala

stanga

Lobul inferior drept

Lobul superior

stang

Bronhia principala

dreapta

Lobul superior

drept

Lobul inferior stang

Bronhii lobareLobul inferior drept

Lobul superior

stangCordul

Lobul superior

drept

Lobul inferior stang

Lobul inferior drept

Lobul superior

stangCordul

Lobul mijlociu

drept