TY - JOUR
T1 - Reversed halo sign on computed tomography
T2 - State-of-the-art review
AU - Marchiori, Edson
AU - Zanetti, Gláucia
AU - Hochhegger, Bruno
AU - Irion, Klaus L.
AU - Carvalho, Antonio Carlos Pires
AU - Godoy, Myrna C.B.
N1 - Copyright:
Copyright 2013 Elsevier B.V., All rights reserved.
PY - 2012/8
Y1 - 2012/8
N2 - The reversed halo sign (RHS) is a chest computed tomography (CT) pattern defined as a focal round area of ground-glass attenuation surrounded by a crescent or ring of consolidation. The RHS was first described as being relatively specific for cryptogenic organizing pneumonia but was later observed in several other infectious and noninfectious diseases. Although the presence of the RHS on CT may help narrow the range of diseases considered in differential diagnoses, final diagnoses should be based on correlation with the clinical scenario and the presence of additional disease-specific CT findings. However, frequently a biopsy may be needed to establish the diagnosis. Organizing pneumonia is the most frequent cause of the RHS. This is a distinct clinical and pathologic entity that can be cryptogenic or secondary to other known causes. Morphologic aspects of the halo, particularly the presence of small nodules in the wall or inside the lesion, usually indicate an active granulomatous disease (tuberculosis or sarcoidosis) rather than organizing pneumonia. Immunocompromised patients presenting with the RHS on CT examination should be considered to have an infection until further analyses prove otherwise. Pulmonary zygomycosis and invasive pulmonary aspergillosis are typically seen in patients with severe immunosuppression, most commonly secondary to hematological malignancies. Other causes of the RHS include noninvasive fungal infections such as paracoccidioidomycosis, histoplasmosis, and Pneumocystis jiroveci pneumonia. Furthermore, Wegener's granulomatosis, radiofrequency ablation, and lymphomatoid granulomatosis may also lead to this finding. Based on a search of the Pub Med and Scopus databases, we review the different diseases that can manifest with the RHS on CT.
AB - The reversed halo sign (RHS) is a chest computed tomography (CT) pattern defined as a focal round area of ground-glass attenuation surrounded by a crescent or ring of consolidation. The RHS was first described as being relatively specific for cryptogenic organizing pneumonia but was later observed in several other infectious and noninfectious diseases. Although the presence of the RHS on CT may help narrow the range of diseases considered in differential diagnoses, final diagnoses should be based on correlation with the clinical scenario and the presence of additional disease-specific CT findings. However, frequently a biopsy may be needed to establish the diagnosis. Organizing pneumonia is the most frequent cause of the RHS. This is a distinct clinical and pathologic entity that can be cryptogenic or secondary to other known causes. Morphologic aspects of the halo, particularly the presence of small nodules in the wall or inside the lesion, usually indicate an active granulomatous disease (tuberculosis or sarcoidosis) rather than organizing pneumonia. Immunocompromised patients presenting with the RHS on CT examination should be considered to have an infection until further analyses prove otherwise. Pulmonary zygomycosis and invasive pulmonary aspergillosis are typically seen in patients with severe immunosuppression, most commonly secondary to hematological malignancies. Other causes of the RHS include noninvasive fungal infections such as paracoccidioidomycosis, histoplasmosis, and Pneumocystis jiroveci pneumonia. Furthermore, Wegener's granulomatosis, radiofrequency ablation, and lymphomatoid granulomatosis may also lead to this finding. Based on a search of the Pub Med and Scopus databases, we review the different diseases that can manifest with the RHS on CT.
KW - Computed tomography
KW - Pulmonary diseases
KW - Reversed halo sign
UR - http://www.scopus.com/inward/record.url?scp=84864374886&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84864374886&partnerID=8YFLogxK
U2 - 10.1007/s00408-012-9392-x
DO - 10.1007/s00408-012-9392-x
M3 - Review article
C2 - 22573292
AN - SCOPUS:84864374886
SN - 0341-2040
VL - 190
SP - 389
EP - 394
JO - Lung
JF - Lung
IS - 4
ER -