Chest Radiography Interpretation Dr. Raghu Ram Uppalapati

Lung Anatomy Trachea Carina Right and Left Pulmonary Bronchi Secondary Bronchi Tertiary Bronchi Bronchioles Alveolar Duct Alveoli

Lung Anatomy Right Lung Left Lung Superior lobe Middle lobe Inferior lobe Left Lung

Lung Anatomy on Chest X-ray PA View: Extensive overlap Lower lobes extend high Lateral View: Extent of lower lobes

Lung Anatomy on Chest X-ray 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 4th right anterior rib 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 4th right anterior rib.

Lung Anatomy on Chest X-ray The right middle lobe is typically the smallest of the three, and appears triangular in shape, being narrowest near the hilum The right middle lobe is typically the smallest of the three, and appears triangular in shape, being narrowest near the hilum.

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. 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; there is considerable overlap between the more anterosuperiorly located RUL and the RLL. Similarly, the deep posterior gutters extend considerably inferiorly; with full inspiration, the lower lobe can extend may as low as L2, becoming superimposed over the upper poles of the kidneys.

Lung Anatomy on Chest X-ray 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. Oriented obliquely, the major fissure extends posteriorly and superiorly approximately to the level of the fourth vertebral body. Grossly, these lobes can be separated from one another by two fissures which anatomically correspond to the visceral pleural surfaces of those lobes from which they are formed. The minor fissure separates the RUL from the RML, and thus represents the visceral pleural surfaces of both of these lobes. The minor fissure is oriented horizontally, extending ventrally from the chest wall, and extending posteriorly to meet the major fissure. Generally, the location of the minor fissure is approximately at the level of the fourth vertebral body and crosses the right sixth rib in the midaxillary line. The right major fissure is more expansive in size than the minor fissure, separating the right upper and middle lobes from the larger right lower lobe. Oriented obliquely, the major fissure extends posteriorly and superiorly approximately to the level of the fourth vertebral body. The major fissure extends anteroinferiorly, intersecting the diaphragm at the anterior cardiophrenic angle

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 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; left upper

Lt Lower Lobes Left lower lobes and left lower lobes

Lung Anatomy on Chest X-ray 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. 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. It is important to understand that in most individuals, interlobar fissures are usually not completely formed; in some individuals there may be complete absence of a fissure thus losing the demarcation between lobes on gross examination. In general, fissures are not readily identifiable on plain films, with only small portions typically visualized at best. This is because fissures which are composed of only two layers of visceral pleura, may not present a significant radiographic interface and will not produce a shadow. However, if there is fluid within the pleural space or if the visceral pleura is thickened, fissures may be seen in their entirety.

RUL (Right Upper Lung)

RML (Right Middle Lung)

RLL (Right Lower Lung)

LUL (Left Upper Lung)

LLL (Left Lower Lung)

Left Side Fissure LUL LLL

Chest Radiography: Basic Principles A structure is rendered visible on a radiograph by the juxtaposition of two different densities

Silhouette Sign Loss of the expected interface normally created by juxtaposition of two structures of different density No boundary can be seen between two structures of similar density

Right Lower Lobe Pneumonia

Differential X-Ray Absorption The absence of a normal interface may indicate disease; The presence of an unexpected interface may also indicate disease The presence of interfaces can be used to localize abnormalities

Chest Radiographic Patterns of Disease Air space opacity Interstitial opacity Nodules and masses Lymphadenopathy Cysts and cavities Lung volumes Pleural diseases

LUL Pneumonia

Air Space Opacity Components: air bronchogram: air-filled bronchus surrounded by airless lung confluent opacity extending to pleural surfaces segmental distribution

Air Space Opacity: DDX Blood (hemorrhage) Pus (pneumonia) Water (edema) hydrostatic or non-cardiogenic Cells (tumor) Protein/fat: alveolar proteinosis and lipoid pneumonia

Interstitial Opacity: Small Nodules

Interstitial Opacity: Lines

Interstitial Opacity: Lines & Reticulation

Interstitial Opacity Hallmarks: small, well-defined nodules lines interlobular septal thickening fibrosis reticulation

Interstitial Opacity: DDX Idiopathic interstitial pneumonias Infections (TB, viruses) Edema Hemorrhage Non–infectious inflammatory lesions sarcoidosis Tumor

Nodules and Masses Nodule: any pulmonary lesion represented in a radiograph by a sharply defined, discrete, nearly circular opacity 2-30 mm in diameter Mass: larger than 3 cm

Nodules and Masses Qualifiers: single or multiple size border definition presence or absence of calcification location

Well-Defined Calcification Ill-Defined Mass

Lymphadenopathy Non-specific presentations: Specific patterns: mediastinal widening hilar prominence Specific patterns: particular station enlargement

Right Paratracheal Lymphadenopathy

Right Hilar LAN

Right Hilar LAN

Left Hilar LAN

Subcarinal LAN *

AP Window LAN

Cysts & Cavities Cyst: abnormal pulmonary parenchymal space, not containing lung but filled with air and/or fluid, congenital or acquired, with a wall thickness greater than 1 mm epithelial lining often present

Cysts & Cavities Cavity: Abnormal pulmonary parenchymal space, not containing lung but filled with air and/or fluid, caused by tissue necrosis, with a definitive wall greater than 1 mm in thickness and comprised of inflammatory and/or neoplastic elements

Cysts & Cavities Characterize: wall thickness at thickest portion inner lining presence/absence of air/fluid level number and location

Benign Lung Cyst : PCP Pneumatocele Uniform wall thickness 1 mm Smooth inner lining

Benign Cavities : Cryptococcus max wall thickness 4 mm minimally irregular inner lining

Indeterminate Cavities max wall thickness 5-15 mm mildly irregular inner lining

Malignant Cavities: Squamous Cell Ca max wall thickness 16 mm Irregular inner lining

Pleural Disease: Basic Patterns Effusion angle blunting to massive mobility Thickening distortion, no mobility Mass Air Calcification

Pleural Effusion

Pleural Effusion

Pleural Calcification

SOME INTERESTING X-RAYS & DISCUSSIO N

Chest breast implants

Tip of ET Pneumomediastinum

Potential X ray findings wide mediastinum obliteration of aortic knob Rt mainstem shift up and right NG deviate to right pleural cap Major Vessel Injury

Expiration reduces lung volume, making a small pneumo easier to see

Irregular linear opacities are present in both lungs, especially in the periphery and the bases of the lungs. The heart is slightly enlarged, but this is not related to the pulmonary abnormalities in this case.

Hodgkin’s Disease

A single, 3cm relatively thin-walled cavity is noted in the left midlung. This finding is most typical of squamous cell carcinoma (SCC). One-third of SCC masses show cavitation

LUL Atelectasis: Loss of heart borders/silhouetting LUL Atelectasis: Loss of heart borders/silhouetting. Notice over inflation on unaffected lung

Right Middle and Left Upper Lobe Pneumonia

Pseudotumor: fluid has filled the minor fissure creating a density that resembles a tumor (arrow). Recall that fluid and soft tissue are indistinguishable on plain film. Further analysis, however, reveals a classic pleural effusion in the right pleura. Note the right lateral gutter is blunted and the right diaphram is obscurred.

Pneumonia:a large pneumonia consolidation in the right lower lobe Pneumonia:a large pneumonia consolidation in the right lower lobe. Knowledge of lobar and segmental anatomy is important in identifying the location of the infection

24 hours after diuretic therapy

CHF:a great deal of accentuated interstitial markings, Curly lines, and an enlarged heart. Normally indistinct upper lobe vessels are prominent but are also masked by interstitial edema.