 Neutropaenic patients with febrile episodes that are unresponsive to standard secondline broadspectrum antibiotics combination currently meropenem and vancomycin will be referred for a contrastenhanced thin section continuous volume CT scan. The purpose of this CT study is primarily to support the clinical suspicion of a diagnosis of IA and to determine its morphological extent. The purpose of the contrast injection is to test the hypothesis that in patients with IA, regions of necrotic lung in contrast to other inflammatory or infective lesions should not demonstrate any contrast enhancement. 