Thomas R, et al. - Via a total of 70 patients with hematologic malignancy, neutropenia, or history of solid organ transplant or stem cell transplant who had the reverse halo sign (RHS) at chest CT were involved in this study by the experts in order to evaluate the most prevalent causes of the RHS in immunocompromised patients and to recognize clinicoradiologic characteristics that aid in attaining a particular diagnosis. Followed by organizing pneumonia, infection, including fungal and bacterial pneumonia, was the most prevalent cause of the RHS. In the solid organ transplant group, noninfectious causes including organizing pneumonia were more likely, whereas, in patients with hematologic malignancy and stem cell transplant, infections were more likely. Aspergillosis among fungal pneumonia was as prevalent as mucormycosis. Neutropenia, rim thickness, central ground-glass attenuation, and lesion diameter associated with an infectious cause. A decision tree using neutropenia, rim thickness, central ground-glass attenuation, and pleural effusion could distinguish infectious from noninfectious cause with an accuracy of 78%, in comparison with radiologist accuracy of 81%. Therefore, infections were concluded as more likely reason to cause RHS in comparison with noninfectious processes in immunocompromised patients, and aspergillosis may be as likely overall as mucormycosis due to its greater incidence in these patients. A decision tree using clinical and imaging characteristics can help distinguish infectious from noninfectious causes of RHS.