Submitted by PPG Medicina e Ci?ncias da Sa?de (medicina-pg@pucrs.br) on 2018-09-03T12:29:41Z No. of bitstreams: 1 GIORDANO_RAFAEL_TRONCO_ALVES.pdf: 4296387 bytes, checksum: 0ebd26ada0ccec344a04ffbbd329dfae (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-09-03T14:24:25Z (GMT) No. of bitstreams: 1 GIORDANO_RAFAEL_TRONCO_ALVES.pdf: 4296387 bytes, checksum: 0ebd26ada0ccec344a04ffbbd329dfae (MD5) / Made available in DSpace on 2018-09-03T14:30:50Z (GMT). No. of bitstreams: 1 GIORDANO_RAFAEL_TRONCO_ALVES.pdf: 4296387 bytes, checksum: 0ebd26ada0ccec344a04ffbbd329dfae (MD5) Previous issue date: 2018-08-13 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Introduction: The halo sign consists of an area of ground-glass opacity surrounding pulmonary lesions on chest computed tomography (CT) scans. Different diseases have already been described as causing this finding, though a larger and more objective analysis of this sign has not been conducted yet. Materials and methods: The authors compared CT images of immunocompetent and immunosuppressed patients in terms of halo sign features and seek to identify those of greatest diagnostic value. An observational study of exams performed between January of 2011 and May of 2015 was carried out. After initial database search with keywords, two thoracic radiologists reviewed the scans in order to determine the number of lesions, as well as their distribution, size, and contour, together with halo thickness and any other associated findings. The study obtained approval by the institutional ethics committee. The chi-squared test, Student t test and Mann-Whitney U test were adopted according to sample characteristics, with a bilateral level of significance of 0.05. Results: A total of 85 patients (46 male, 54%) were evaluated, with 53 (62%) immunocompetent and 32 (38%) immunosuppressed. The main diagnosis among immunocompetents was lung cancer (n=32, 64%), whereas aspergillosis was the main condition in immunosuppressed patients (n=25, 78%). Multiple and randomly distributed lesions were more frequent in the immunosuppressed group (p<0.001), with halo thickness also greater in this group (p<0.05). Conclusions: We concluded that the causes of the halo sign differ significantly according to immune status, and that halo thickness, the number and the distribution of lesions are the data with greatest diagnostic value. / Introdu??o: O sinal do halo consiste em uma ?rea de opacidade em vidro-fosco ao redor de les?es pulmonares em imagens de tomografia computadorizada (TC) de t?rax. Diferentes doen?as j? foram descritas como causadoras deste achado, por?m uma an?lise maior e mais objetiva deste sinal ainda n?o foi conduzida. Materiais e m?todos: Os autores compararam imagens tomogr?ficas de pacientes imunocompetentes e imunocomprometidos quanto a caracter?sticas do sinal do halo, a fim de identificar as de maior valor diagn?stico. Realizou-se um estudo observacional de exames realizados entre janeiro de 2011 e maio de 2015. Ap?s busca inicial em banco de dados com palavras-chave, dois radiologistas tor?cicos analisaram os exames para determinar o n?mero de les?es e sua distribui??o, tamanho e contorno, bem como a espessura do halo e outros achados associados. O estudo obteve aprova??o do comit? de ?tica institucional. Os testes de Qui-quadrado, t de Student e U de Mann-Whitney foram adotados de acordo com caracter?sticas amostrais, com um n?vel de signific?ncia de 0,05 bilateral. Resultados: Um total de 85 pacientes (46 homens, 54%), foram avaliados, sendo 53 (62%) imunocompetentes e 32 (38%) imunocomprometidos. O principal diagn?stico entre os imunocompetentes foi o de neoplasia pulmonar (n=32, 64%), enquanto a aspergilose foi a principal condi??o entre imunocomprometidos (n=25, 78%). Les?es m?ltiplas e de distribui??o rand?mica foram mais frequentes no grupo imunocomprometido (p<0,001), sendo a espessura do halo tamb?m maior neste grupo (p<0,05). Conclus?es: Conclui-se que as causas de sinal do halo diferem significativamente de acordo com o estado imunol?gico, sendo a espessura do halo, o n?mero e a distribui??o das les?es os dados de maior valor diagn?stico.