The following clinical indications apply to the Computerized Axial Tomography
(CT or CAT) of the thorax:

  * Evaluation of pulmonary, mediastinal, pleural and chest wall infections and their complications
  * Detection and characterization of mediastinal neoplasms and other processes
  * Assessment of cardiopulmonary failure or insufficiency
  * Diagnosis and/or staging of neoplastic and hematologic processes arising in the thorax or with potential involvement of the thorax
  * Detection and determination of nature and extent of cardiovascular abnormalities such as, but not limited to aneurysm, dissection, embolism, thrombosis, congenital anomalies, postoperative complications and sequelae of atherosclerotic disease
  * For assessing and/or guiding drainage of pulmonary or pleural fluid collections such as abscess, empyema, effusion or pneumothorax
  * For characterizing and follow-up evaluation of interstitial and alveolar lung disease due to idiopathic, allergic, collagen-vascular, environmental or other causes
  * For evaluating thoracic sequelae of remote processes including, but not limited to, pancreatitis, gastrointestinal perforation and other processes
  * For assessing injury, potential injury or thoracic sequelae after trauma, burn, surgery, transplantation, radiation therapy, chemotherapy or invasive procedure such as pacemaker placement, chest tube placement or mechanical ventilation
  * Evaluation of the patient with symptoms that may be arising from the chest, or be referred to the chest including but not limited to cough, hemoptysis, chest pain, abdominal pain and others
  * To further characterize a suspected abnormality detected by another imaging test
  * Evaluation of a patient with myasthenia gravis to rule out thymic tumors
  * Performance of CT-guided biopsies and drainage procedures when fluoroscopy is inadequate
  * The most common symptom of an aortic dissection (occurring in approximately 90% of the cases) is sudden, excruciating pain most commonly located in the anterior chest. Patients may describe the pain as "cutting," "ripping," or "tearing". A sudden neurologic episode usually accompanies the onset of most instances of "painless" aortic dissection.

**NOTE:** Radiologic examinations of the chest represent the basic diagnostic
tests used to identify abnormalities of the thorax. The chest x-ray and/or
physical examination should be used to evaluate patients who present with
signs and/or symptoms suggestive of chest pathology prior to proceeding to a
CT scan.  
  
In addition to the medical necessity requirements, the CT scan must be
performed on a model of CT equipment that is recognized by the Food and Drug
Administration (FDA) and has achieved the full market phase of development.

In keeping with American College of Radiology (ACR) Practice Guidelines and
Technical Standards, CT thorax should be provided by qualified radiology
personnel (radiology technicians, diagnostic radiologists). The patient's
condition should be monitored throughout the procedure. As this involves the
patient being in a closed environment, claustrophobia or medical problems
exacerbated by the enclosure may be exhibited.  
  
Qualified physicians (such as board-certified radiologists) should perform the
interpretation of the films.  
  
The CT service should be furnished only when clinically appropriate for the
patient's symptoms or complaint. When performed as a screening function, it
will not be covered.