Chapter 3: PRINCIPLES OF CARDIOVASCULAR IMAGING

PRINCIPLES OF CARDIOVASCULAR IMAGING

CHEST RADIOGRAPHS

Justin B. Joines

Cedric Lefebvre

Technology/Technique

Chest radiographs are the most commonly performed diagnostic radiographs in emergency departments. A chest radiograph can help identify cardiovascular emergencies and other medical problems such as pneumothorax, pulmonary edema, aortic dissection, pneumonia, perforation of the gastrointestinal tract, fractures, masses, and foreign bodies (Table 3.1).

TABLE 3.1

MEDICAL CONDITIONS AND ASSOCIATED FINDINGS ON CHEST RADIOGRAPH

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TABLE 3.1

MEDICAL CONDITIONS AND ASSOCIATED FINDINGS ON CHEST RADIOGRAPH

Diagnosis

Important Finding

Pulmonary edema

Vascular congestion, increased cephalization of vascular flow

Pneumothorax

Absence of lung markings, deep sulcus sign, mediastinal deviation

Aortic dissection/aneurysm

Abnormal mediastinum, aortic knob or cardiac contour; pleural effusions, displaced intimal calcification, tracheal deviation

Pneumonia

Focal or lobar consolidation, localized infiltration, patchy opacifications

Cardiac tamponade

Possible presence of enlarged cardiac silhouette

Pulmonary embolus

Westermark sign, Hamptons hump, atelectasis

Esophageal rupture

Widened mediastinum, free air

A radiograph, or “x-ray,” is customarily performed by a trained radiologic technician. The x-ray apparatus typically consists of x-ray film or a special plate that digitally records the picture and an x-ray tube. The x-ray film is positioned next to the patient while the x-ray tube is located at a distance of about 6 feet from the patient. Two views are taken for a conventional chest radiograph: a posterior–anterior (PA) view, in which the x-ray beam passes through the chest from the back, and a lateral view such that x-rays pass through the chest from one side to the other. When the clinical scenario mandates a portable radiograph at the bedside, an anterior–posterior (AP) view can be obtained with the patient in a seated position. The technician may use a lead apron to protect certain parts of the patient’s body (eg, reproductive organs) from radiation. The amount of radiation used in a chest radiograph is relatively small and confers approximately 0.1 milli-severts (1/10,000 Sv) to the patient.

FIGURE 3.1

The conventional PA view of a chest radiograph provides an image of the lungs, heart, great vessels, mediastinum, ribs, clavicles, trachea, esophagus, spine, and diaphragms.