Improved Radiographic Imaging of Invasive Fungal Disease: The Cornerstone to Antifungal Stewardship in the Hematology Units?

Empirical or fever-driven antifungal treatment strategies are widely recognized to result in overtreatment of patients and excessive cost. As a result, diagnostic-driven approaches for managing invasive fungal diseases (IFDs) in hematology units have been proposed that rely on early non-specific radiologic findings frequent testing with non-culture-based biomarkers (e.g., galactomannan, PCR) as a trigger for antifungal treatment. However, the performance of these non-culture-based biomarker tests varies significantly from one center to the next, and their sensitivity is reduced by prior antifungal therapy. Moreover, many clinicians do not have sufficient confidence in their negative predictive value to withhold antifungal treatment. An alternative strategy is to use existing (computer tomography pulmonary angiography) and developing technologies (immune-positron emission tomography with specific antibodies) to improve the sensitivity and specificity radiological for IFD. Currently available data suggest that these newer techniques may have similar or better diagnostic performance as biomarker tests with high negative predictive values. In this monograph, we review challenges and recent progress in radiological imaging of IFD in hematology patients, and discuss its potential implications for antifungal stewardship.