Date: 26 November 2013
Halo sign in IPA
Copyright: n/a
Notes:
CT scan of a neutropenia patient with leukaemia who has 2 lesions. One, on the right, is nodular, abuts on the pleura and is surrounded by a (grey) low attenuation area, referred to as the “halo” sign. This is virtually only seen in invasive fungal infections of the lung, especially early in the course of the disease, during neutropenia. The other lesion visible on this scan, posteriorly on the left, is also typical of invasive pulmonary aspergillosis in that it is pleura-based and has sharply angulated sides typical of vascular invasion and infarction of small lung segments. There is the suggestion of a “halo” sign anteriorly, but there is less confidence in this appearance (compared with the other) because it is only on one side of the lesion.
Images library
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Bronchoscopic manifestations of Aspergillus tracheobronchitis. (a) Type I. Inflammatory infiltration, mucosa hyperaemia and plaques of pseudomembrane formation in the lumen without obvious airway occlusion. (b) Type II. Deep ulceration of the bronchial wall. (c) Type III. Significant airway occlusion by thick mucous plugs full of Aspergillus without definite deeper tissue invasion. (d) Type IV. Extensive tissue necrosis and pseudomembrane formation in the lumen with airway structures and severe airway occlusion (Wu 2010).
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High resolution CT showing centrilobular nodular opacities and branching linear opacities (tree-in-bud appearance) (Al-Alawi 2007).
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Chest X-ray showing poorly defined bilateral nodular opacities (Al-Alawi 2007).
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Gross pathologic specimen from autopsy shows the bronchial lumen covered by multiple whitish endobronchial nodules (arrows) (Franquet 2002).
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Invasive tracheobronchitis showing numerous nodules seen during bronchoscopy (Ronan D’Driscoll).
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Pseudomembranous seen overlying the bronchial mucosa (Tasci 2006).
