Pneumonia in febrile neutropenic patients: radiologic diagnosis.

Pneumonia in febrile neutropenic cancer patients should be diagnosed as early as possible, because prompt institution of targeted therapeutic measures might be essential for their prognosis. Conventional chest radiographs frequently fail to detect lung infiltrates at an early stage, meaning that a normal chest radiograph finding must be interpreted with caution. Thoracic computed tomograph scans provide a much higher yield and are therefore recommended in patients at risk for a complicated pulmonary infection. Lung infiltrates documented by computed tomograph scans (eg, nodular infiltrates with or without a halo, ground-glass opacities, or cavitations with or without air crescent signs) open up a wide range of differential diagnoses, such as invasive pulmonary aspergillosis, other types of pneumonia, hemorrhage, infiltration by the underlying malignancy, drug toxicity, alveolar proteinosis, or acute respiratory distress syndrome. High-resolution techniques or magnetic resonance imaging may provide further details to help distinguish inflammatory processes from processes that may not require an antimicrobial intervention. Sequential nonculture-based monitoring for invasive fungal infections, using Aspergillus antigen sandwich enzyme-linked immunosorbent assay, and panfungal or Aspergillus-specific polymerase chain reaction, may add important tools in the early identification of patients who may benefit from systemic antifungal treatment.