Chest Computed Tomography of Late Invasive Aspergillosis after Allogeneic Hematopoietic Stem Cell Transplantation

Abstract

Computed tomography (CT) is a powerful diagnostic tool for invasive aspergillosis (IA) after allogeneic stem cell transplantation (allo-SCT); however, little information is available concerning CT findings of late IA after allo-SCT. To characterize CT findings of late IA, we retrospectively examined medical records and high-resolution CT findings of 27 allo-SCT recipients with late IA. Either acute or chronic GVHD was diagnosed in 24 patients. All 27 patients were given corticosteroids at IA diagnosis. High-resolution CT findings included halo (n=12), centrilobular nodules (n=12), ill-defined consolidation (n=13), ground-glass attenuation (n=8), pleural effusion (n=7), pleural-based consolidation (n=4), and cavitation (n=4). CT findings showing centrilobular nodules and either halo or cavitation were classified into bronchopneumonia type and angioinvasive type, respectively. Angioinvasive-type, bronchopneumonia-type, and combination-type IA were diagnosed in 11, 8, and 4 patients, respectively. CT findings were nonspecific in the other 4 patients. One bronchopneumonia-type case and 2 angioinvasive-type IA cases were subsequently diagnosed as combination type. Although there were no significant differences in patient characteristics between the 2 types of IA, bronchopneumonia-type IA had a poorer prognosis than angioinvasive IA ( P=.022). Halo is a useful diagnostic marker in late IA as well as early IA, and late IA frequently manifests as bronchopneumonia.

The strategy for the diagnosis of invasive pulmonary aspergillosis should depend on both the underlying condition and the leukocyte count of patients with hematologic malignancies

“…Most previous studies concerning the clinical presentation of IPA have focused on neutropenic AL patients, 5,32 whereas fewer data are available on IPA occurring in allogeneic HSCT recipients 9,33 or in patients with another hematologic disorder. In addition, to our knowledge, no previous studies have compared the characteristics of IPA in these different patients.…”

“…In contrast, the presence of centrilobular micronodules and/or tree-in-bud without any nodule with a halo sign was defined as an airway-invasive disease ( Figure 1B). 7,9,[11][12][13] As consolidations may occur with both aspergillosis-induced hemorrhagic infarctions (ie, angioinvasive disease) and Aspergillus bronchopneumonia (ie, airway-invasive disease), consolidations were not considered when differentiating between the 2 entities. 10,12,13 Fiberoptic bronchoscopy was performed within 24 hours of the baseline HRCT.…”

“…7 Some recent data have shown that other CT scan findings may be the only signs present in non-neutropenic patients with IPA, demonstrating the necessity of considering these less characteristic CT scan features for the diagnosis of IPA. 8,9 In this context, some authors have previously identified 2 different patterns of IPA, relying on correlations between histology and CT scan patterns: angioinvasive pulmonary aspergillosis is characterized by vascular invasion by Aspergillus and a nodule with a halo sign, whereas airway-invasive aspergillosis is characterized by the destruction of the bronchiolar wall by Aspergillus and centrilobular micronodules and tree-in-bud opacities. [9][10][11][12][13] In the last few years, breakthrough infections with new Aspergillus species and other fungi, whose sensitivity to the various antifungal drugs is variable, have been reported.…”

“…8,9 In this context, some authors have previously identified 2 different patterns of IPA, relying on correlations between histology and CT scan patterns: angioinvasive pulmonary aspergillosis is characterized by vascular invasion by Aspergillus and a nodule with a halo sign, whereas airway-invasive aspergillosis is characterized by the destruction of the bronchiolar wall by Aspergillus and centrilobular micronodules and tree-in-bud opacities. [9][10][11][12][13] In the last few years, breakthrough infections with new Aspergillus species and other fungi, whose sensitivity to the various antifungal drugs is variable, have been reported. [14][15][16][17] As clinical presentation does not allow for the differentiation of the causative organisms of invasive fungal infections, direct mycologic tests are now recommended for both epidemiologic reasons and for the optimal management of the patients.…”

Early diagnosis of invasive pulmonary aspergillosis in hematologic patients: an opportunity to improve the outcome

“…The bronchoalveolar phase of IPA has been described in non-neutropenic patients, and presents different and usually 'non-specific' radiological findings, including areas of peribronchial consolidations, micro (<1 cm) centrilobular nodular opacities, ground-glass infiltrates, branching linear or nodular opacities with a 'treein-bud' appearance, and focal areas of bronchiectasis. 5,13 The impact of neutrophil counts in determining the predominant form of IPA was described in a recently published paper by Bergeron et al that analyzed the radiological picture of 55 patients with proven or probable IPA.…”