الفهرس 
Anatomy of the Lungs and its Blood SupplyOnly 14 pages are availabe for public view
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Abstract
The diagnosis of pulmonary embolism (PE) remains a major clinical problem. Because of variable and nonspecific symptoms, imaging is required to establish the diagnosis.
The advent of chest CT scanning for the diagnosis of pulmonary embolism was hailed as an improvement, even before recent studies were undertaken. By 2001, CT scanning was being used more often than lung scanning to investigate suspected pulmonary embolism.
There are now multiple generations of CT scanners, but even first generation machines delivered images that were dramatic in clarity, rapidly acquired, and accurate in delineating the proximal pulmonary arterial tree. This noninvasive technology has evolved rapidly. A 16-slice multidetector-row CT scanner can image the entire chest with submillimeter resolution and requires a breath-hold of less than 10 seconds.
MDCT pulmonary angiography and venography for suspected venous thromboembolism are safe, readily available, and increasingly being used. Recent advances in technology allow faster scanning, thinner images, and more reproducible interpretations.
The most important advantage of CT over other imaging modalities is that both mediastinal and parenchymal structures are evaluated, and thrombus is directly visualized. Studies have shown that up to two thirds of patients with an initial suspicion of PE receive another diagnosis , some with potentially life-threatening diseases, such as aortic dissection, pneumonia, lung cancer, and pneumothorax. Most of these diagnoses are amenable to CT visualization, so that in many cases a specific etiology for the patients’ symptoms and important additional diagnoses can be established