Reversed Halo Sign in Invasive Pulmonary Fungal Infections

Abstract Pulmonary fungal infections, which can be opportunistic or endemic, lead to considerable morbidity and mortality. Such infections have multiple clinical presentations and imaging patterns, overlapping with those of various other diseases, complicating the diagnostic approach. Given the immensity of Brazil, knowledge of the epidemiological context of pulmonary fungal infections in the various regions of the country is paramount when considering their differential diagnoses. In addition, defining the patient immunological status will facilitate the identification of opportunistic infections, such as those occurring in patients with AIDS or febrile neutropenia. Histoplasmosis, coccidioidomycosis, and paracoccidioidomycosis usually affect immunocompetent patients, whereas aspergillosis, candidiasis, cryptococcosis, and pneumocystosis tend to affect those who are immunocompromised. Ground-glass opacities, nodules, consolidations, a miliary pattern, cavitary lesions, the halo sign/reversed halo sign, and bronchiectasis are typical imaging patterns in the lungs and will be described individually, as will less common lesions such as pleural effusion, mediastinal lesions, pleural effusion, and chest wall involvement. Interpreting such tomographic patterns/signs on computed tomography scans together with the patient immunological status and epidemiological context can facilitate the differential diagnosis by narrowing the options.

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El Signo De Halo Invertido En Tomografía Computada De Tórax [The Inverted Halo Sign in Thoracic Computed Tomography]

Revista Médica de Panamá - ISSN 2412-642X ◽

10.37980/im.journal.rmdp.2020832 ◽

2020 ◽

Vol 40 (1) ◽

Author(s):

Rolando Reyna ◽

Karen Souza

Keyword(s):

Fungal Infections ◽

Ground Glass Opacity ◽

Pneumocystis Pneumonia ◽

Community Acquired Pneumonia ◽

Wegener Granulomatosis ◽

Lipoid Pneumonia ◽

Halo Sign ◽

Thoracic Computed Tomography ◽

Wide Range ◽

Reversed Halo Sign

ResumenEl signo del halo invertido se caracteriza por una opacidad central de vidrio esmerilado rodeado por una consolidación del espacio aéreo más densa en forma de una media luna o un anillo. El signo del halo invertido se ha informado en asociación con un amplia gama de enfermedades pulmonares, incluidas las infecciones fúngicas pulmonares invasivas, neumonía por pneumocystis, tuberculosis, neumonía adquirida en la comunidad, granulomatosis linfomatoide, granulomatosis de Wegener, neumonía lipoidea y sarcoidosis. También se observa en neoplasmas pulmonares e infarto y después de radioterapia y ablación por radiofrecuencia de neoplasias malignas pulmonares. También es conocido como signo de halo en reversa o signo del atolón.AbstractThe reversed halo sign is characterized by a central ground-glass opacity surrounded by denser air–space consolidation in the shape of a crescent or a ring. The reversed halo sign has been reported in association with a wide range of pulmonary diseases, including invasive pulmonary fungal infections, pneumocystis pneumonia, tuberculosis, community-acquired pneumonia, lymphomatoid granulomatosis,Wegener granulomatosis, lipoid pneumonia and sarcoidosis. It is also seen in pulmonary neoplasms and infarction, and following radiation therapy and radiofrequency ablation of pulmonary malignancies. It is also known as a reverse halo sign or atoll sign.

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