CT Manifestations of HIV-associated Pulmonary Infections and Noninfectious Mimics in the Era of Antiretroviral Therapy.

Following the introduction of antiretroviral therapy (ART), the prognosis after being diagnosed with HIV infection has changed from a universally fatal disease to a largely manageable chronic condition. Despite these advances, opportunistic infections remain a central challenge, particularly in individuals with declining CD4 T-cell counts. The authors review the pathologic conditions unique to patients living with HIV infection at various levels of disease progression, based on CD4 cell thresholds, and examine how radiologic patterns at CT can guide differential diagnoses in the post-ART age. A CT pattern-based radiologic approach-such as consolidation, ground-glass opacities, cavitation, and nodularity-enables radiologists to distinguish between typical bacterial infections, opportunistic fungal or mycobacterial processes, and less common viral causes in addition to their many mimics. Immune reconstitution inflammatory syndrome (IRIS) further complicates the diagnostic algorithm, as newly reconstituted immune activity after initiation of ART can unmask previously subclinical infections or worsen known ones. The overlapping clinical and imaging features of IRIS with opportunistic disease underscore the need for vigilant monitoring and a nuanced interpretation of radiologic findings. Additionally, lymphadenopathy in patients living with HIV infection is a common CT finding with a broad differential diagnosis, which can be narrowed if one is attuned to certain characteristics useful in differentiating underlying disease. In this comprehensive overview, the authors highlight the critical role of using CD4 cell counts with a pattern-based approach to interpreting radiologic studies in optimizing care for people living with HIV infection. ©RSNA, 2026 Supplemental material is available for this article.