Chest Radiography and Clinical Indications

Flashcards summarizing clinical indications, exposure adjustments, positioning criteria, and central ray specifications for chest and upper airway radiographic examinations.

Dyspnea

Difficult breathing.

Atelectasis

Collapse of all or a portion of the lung, appearing radiographically as radiodense lung regions with a shift of the heart and trachea in severe cases.

Emphysema

A pulmonary condition characterized by increased lung dimensions, barrel chest, flattened diaphragm, and radiolucent lungs, requiring a significantly decreased exposure factor adjustment.

Respiratory Distress Syndrome (RDS)

Commonly called hyaline membrane disease (HMD) in children, characterized radiographically by a granular pattern of increased radiodensity throughout the lungs and possible air-fluid levels.

Hampton Hump

A wedge-shaped opacity rarely demonstrated on chest radiographs in cases of pulmonary emboli.

PA Chest Projection (Respiration & Rib Visualization)

Exposure is made at the end of the second full inspiration, which visualizes a minimum of $10$ posterior ribs above the diaphragm ($11$ on many patients).

PA Chest Projection (CR Centering)

Central ray is perpendicular to the IR and centered to the midsagittal plane at the level of T7 ($7\text{ to }8\text{ inches}$ [$18\text{ to }20\text{ cm}$] below the vertebra prominens).

Lateral Chest Projection (Rotation Evaluation)

Rotation is evaluated by checking if the posterior ribs and costophrenic angle on the side away from the IR are projected slightly ($1/4\text{ to }1/2\text{ inch}$ [or about $1\text{ cm}$]) posterior due to beam divergence.

AP Chest Projection (CR Angle)

Central ray is angled caudad to be perpendicular to the long axis of the sternum (generally requires a $+5^\text{o}$ caudad angle) to prevent clavicles from obscuring the apices.

Anterior Oblique Chest Positions (Side of Interest)

Chest oblique projections where the side of interest generally is the side farthest from the IR (e.g., RAO provides the best visualization of the left lung).

Posterior Oblique Chest Positions (Side of Interest & Correspondence)

Chest oblique projections providing the best visualization of the side closest to the IR, where RPO corresponds to the LAO position and LPO corresponds to the RAO position.

Lateral Upper Airway Projection (CR Centering)

Central ray is perpendicular to the center of the IR at the level of C6 or C7, midway between the laryngeal prominence of the thyroid cartilage and the jugular notch.

AP Upper Airway Projection (Positioning Line & CR)

Positioning where the acanthiomeatal line is perpendicular to the IR, with the central ray directed perpendicular to T1-T2, about $1\text{ inch}$ ($2.5\text{ cm}$) above the jugular notch.

Gothic Arch Sign

A smooth, tapered narrowing of the subglottic portion of the trachea seen in croup on an AP upper airway radiograph.