Pneumonia
Pneumonia is an infection of the lungs that causes inflammation and fluid buildup within the air sacs (alveoli). This can make it difficult to breathe and may lead to symptoms such as cough, fever, and shortness of breath. Pneumonia can be caused by bacteria, viruses, or fungi, and can range from mild to severe depending on the patient’s age, health, and the organism involved. Imaging is often used to confirm the diagnosis and assess the extent of involvement.
What is it?
Pneumonia occurs when an infection causes the lung’s air sacs to fill with fluid, pus, or inflammatory material. This limits normal gas exchange and leads to symptoms such as cough, fever, and breathing difficulty. The infection can involve a small portion of the lung or spread across multiple lobes depending on the cause and severity.
Many organisms can cause pneumonia, including bacteria like Streptococcus pneumoniae, viruses such as influenza or COVID-19, and less commonly fungi. Imaging plays a key role in identifying pneumonia and assessing its pattern—such as lobar consolidation, patchy infiltrates, or ground-glass opacities—each of which can offer clues about the underlying cause.
Important to Know
Pneumonia can range from mild to life-threatening. High fever, worsening shortness of breath, persistent chest pain, or coughing up blood should prompt urgent medical evaluation. Older adults, young children, and individuals with chronic health conditions are more likely to develop complications such as respiratory failure or sepsis.
CT scans are especially helpful when pneumonia is severe, atypical, or not improving with treatment. They allow radiologists to check for complications like abscesses, pleural effusions, or blockages in the airways. Follow-up imaging may be recommended to ensure that abnormalities resolve, particularly in people at higher risk for underlying conditions such as lung cancer.