The CT Halo Sign

Nodular Ground-Glass Opacity at Thin-Section CT: Histologic Correlation and Evaluation of Change at Follow-up

“…The surrounding region of ground-glass opacity represents alveolar hemorrhage related to infarction (Fig 10b) (37). Pinto (38) reported that the frequency of the CT halo sign ranged from 96% on day 0 to 19% on day 14 after disease onset. These CT findings may be early indicators of invasive aspergillosis in severely neutropenic febrile patients in whom antibiotic medications are ineffective.…”

Zygomykosen nach Blutstammzelltransplantation—ein aktuelles Problem?

“…Thrombosie- [10,23]. Im späteren Verlauf kön-nen, ebenfalls wie bei der Aspergillose, Kavitationen und Luftsicheln erkennbar sein [1].…”

Diagnosis of Invasive Fungal Infections – Current Limitations of Classical and New Diagnostic Methods

“…154 To be useful for the diagnosis of aspergillosis, the CT scan must be performed within five days of the onset of infection, because ~75% of the initial halo signs disappear within a week. 155 The 'air crescent' sign does not appear until the third week of the illness, and its appearance may be too delayed to be helpful in the diagnosis of invasive aspergillosis. 154 Although usually regarded as an indication of haemorrhagic nodules, the halo sign may also be present when tumour or inflammatory cells infiltrate the lung parenchyma.…”

“…154 Although usually regarded as an indication of haemorrhagic nodules, the halo sign may also be present when tumour or inflammatory cells infiltrate the lung parenchyma. 153,[155][156][157][158][159] The halo has been described in patients with eosinophilic pneumonia, bronchiolitis obliterans organising pneumonia, 160 and tuberculosis, 161 and in patients infected by Mycobacterium avium complex, 155 Coxiella burnetti, 162 cytomegalovirus, herpes simplex virus, 153 and myxovirus. 160 Patients with posttransplantation lymphoproliferative disorders 163 and Wegener granulomatosis may develop the halo sign, 153 as well as some of those who have undergone transbronchial biopsy.…”

“…160 Patients with posttransplantation lymphoproliferative disorders 163 and Wegener granulomatosis may develop the halo sign, 153 as well as some of those who have undergone transbronchial biopsy. 155 Although it is less common, the halo sign may also be observed in non-haemorrhagic nodules, in which case either tumour cells or inflammatory infiltration account for the halo of ground-glass attenuation. 153 Nonetheless, in the appropriate clinical setting, the halo sign is considered to be early evidence of pulmonary aspergillosis even before serologic tests become positive, 164 and it warrants the administration of systemic antifungal therapy.…”