Cardiac Radiology

The mediastinum is the central part of the chest cavity containing many vital structures, such as the heart, great vessels, trachea, thoracic esophagus, lymph nodes, multiple nerves, sympathetic chains, and thoracic spine. Mediastinal pathology (e.g., masses) can be noted on conventional radiographs as part of evaluating chest-related symptoms, or it can be incidentally detected. To elucidate the characteristics of the mediastinal abnormality, further imaging studies are warranted. Common additional modalities are CT and MRI.

X-rays are high-energy particles of electromagnetic radiation used in the medical field for the generation of anatomical images. X-rays are projected through the body of a patient and onto a film, and this technique is called conventional or projectional radiography. As radiation by X-rays can cause adverse effects depending on the absorbed dose, it is necessary to take protective measures to reduce harm. Digital radiography uses the digital data format and allows for the digital manipulation of images. Common uses include evaluation of chest, mediastinal, spinal, and bone/joint conditions. While radiography is still used to visualize head and abdominal structures, more advanced modalities (CT and MRI) are now preferred. Radiography remains an essential component of initial tests in many diseases, given its wide availability, low cost, and ease of operation.

Worldwide, the most frequent cause of death is heart disease. Thus, the common conditions that are evaluated in healthcare facilities are often related to the heart or the cardiovascular system: hypertension, atherosclerotic disease, and heart failure. In radiologic terms, this region is likely the most frequently studied aspect of human anatomy in healthcare delivery settings. Multiple methods are used, including X-ray, CT, MRI, echocardiography, nuclear imaging, and angiography. Each test has its advantages and disadvantages and is obtained on the basis of the clinical presentation, acuity of symptoms, and risks and benefits to the patient. It is important to know the roles of imaging studies to help determine the proper treatment.

Computed tomography (CT) is one of the most commonly used imaging methods because it is widely available, fast, and reliable. CT scans deploy X-rays to obtain cross-sectional images of the body. A CT scanner consists of a tube that rotates around the patient and emits an X-ray beam and a detector that uses specialized software to receive and convert the beam to an image. The ability to create multiple views (axial, sagittal, coronal) and use contrast (intravenous, oral, rectal) allows for enhanced diagnostic yield. Patients are exposed to radiation, and special consideration should be given to patients with a history of iodine allergy, renal disease, or thyroid disease or patients who are pregnant.

Pulmonary, or chest, imaging includes imaging of the lungs and surrounding structures in the thorax. Imaging of the chest represents a substantial portion of the imaging tests that are routinely performed. Common imaging methods include X-ray, CT, MRI, and ultrasonography (US). Each imaging method has advantages and disadvantages. Radiology exams, once completed, are read and interpreted by board-certified, fellowship-trained radiologists; however, most physicians should know the basics of how to interpret these images.