PurposeTo identify differences in the radiological findings of invasive pulmonary aspergillosis (IPA) among patients classified by severity of neutropenia, and differences in underlying disease. Materials and MethodsWe retrospectively reviewed computed tomography (CT) scans from the time of the diagnosis of IPA in 83 hematological malignancy patients with probable or proven IPA according to the EORTC-MSG criteria. We evaluated CT findings (radiological pattern, number of lesions, distribution, and presence of low attenuation area [LAA]), and compared the radiological findings of patients classified by degree of neutropenia with two different indicators (neutrophil count at the onset, and c-d-index) and underlying disease. ResultsNeutropenia at the onset of IPA was associated with an increased frequency of LAA (p < 0.05), especially in FN (p < 0.01). Cases with a c-d-index of ≧5500 showed an increased incidence of the angio-invasive pattern. In contrast, cases with a c-d-index of 0 showed an increased incidence of the airway-invasive pattern (p < 0.05). The airway-invasive pattern was more frequent in cases with MM, while the angio-invasive pattern was more frequent in cases with AML (p < 0.01). Lower-predominant distribution was more frequent and random distribution was less frequent in cases with AML, random distribution was more frequent and lower-predominant distribution was less frequent in cases with ALL, and upper-predominant distribution was more frequent in cases with MDS (p < 0.05). ConclusionsCT features of IPA vary according to the degree of neutropenia and underlying disease.