PET/CT é amplamente utilizada para avaliação de pacientes com neoplasias torácicas. Altos níveis de captação de ¹⁸F-fluordesoxiglicose (FDG) são geralmente vistos em neoplasias, mas também podem ser fisiológicos, decorrentes de artefatos ou ocorrerem em condições benignas, como lesões infecciosas, inflamatórias e iatrogênicas. Por outro lado, alguns tumores malignos podem não captar FDG, como o adenocarcinoma in situ (anteriormente denominado de carcinoma bronquioloalveolar) e tumores carcinoides. Os autores ilustram as principais armadilhas e artefatos na interpretação dos exames torácicos de PET/CT oncológicos, com estratégias para evitar erros de interpretação.

Unitermos:
Armadilhas; Tórax; PET/CT; Oncologia

Autoria

Gustavo de Souza Portes Meirelles Mailing address: Dr. Gustavo de Souza Portes Meirelles, Rua Cincinato Braga, 282, Bela Vista, São Paulo, SP, Brazil, 01333-010. E-mail: gustavo.meirelles@grupofleury.com.br

MD, PhD, Postdoctoral work in PET/CT, Medical Coordinator of the Grupo Fleury, São Paulo, SP, Brazil.Grupo FleuryBrazilSão Paulo, SP, BrazilMD, PhD, Postdoctoral work in PET/CT, Medical Coordinator of the Grupo Fleury, São Paulo, SP, Brazil.

Julia Capobianco

MD, Specialist in PET/CT, Radiologist for the Grupo Fleury, São Paulo, SP, Brazil.Grupo FleuryBrazilSão Paulo, SP, BrazilMD, Specialist in PET/CT, Radiologist for the Grupo Fleury, São Paulo, SP, Brazil.

Marco Antônio Condé de Oliveira

Nuclear Medicine Physician for the Grupo Fleury, São Paulo, SP, Brazil.Grupo FleuryBrazilSão Paulo, SP, BrazilNuclear Medicine Physician for the Grupo Fleury, São Paulo, SP, Brazil.

Mailing address: Dr. Gustavo de Souza Portes Meirelles, Rua Cincinato Braga, 282, Bela Vista, São Paulo, SP, Brazil, 01333-010. E-mail: gustavo.meirelles@grupofleury.com.br

SCIMAGO INSTITUTIONS RANKINGS

Nuclear Medicine Physician for the Grupo Fleury, São Paulo, SP, Brazil.Grupo FleuryBrazilSão Paulo, SP, BrazilNuclear Medicine Physician for the Grupo Fleury, São Paulo, SP, Brazil.

Figuras

Figuras (13)

Thumbnail

Figure 1
Causes of physiological FDG uptake in the thorax.A: A 6-year-old boy, with normal metabolic activity in the thymus. The strategy for differentiating between focal uptake in the anterior mediastinum and a lesion is to look at the normal aspect of the thymus on CT images. B: A 56-year-old man with lung cancer and a forceful cough during the PET/CT examination. FDG PET/CT shows increased metabolic activity in the thoracic muscles, due to vigorous coughing. C: A 31-year-old lactating woman, with normal FDG uptake in the breast. Lactation induces higher metabolic activity in the breasts, which should not be interpreted as disease. D: A 28-year-old man with testicular cancer. Multiple areas of FDG uptake in the supraclavicular regions and in the upper mediastinum, consistent with increased metabolic activity in brown fat, which regulates body weight and temperature and can be activated by satiety or cold environments.

Thumbnail

Figure 2
A 57-year-old female with cough, fever, and multiple centrilobular pulmonary nodules in the superior segment of the left lower lobe (arrows). PET/CT was performed and showed increased FDG uptake (arrow) in the lung nodules. A CT-guided pulmonary biopsy confirmed the diagnosis of pulmonary tuberculosis.

Thumbnail

Figure 3
A 57-year-old man, current smoker, with non-Hodgkin lymphoma and a spiculated pulmonary nodule (arrows) in the left upper lobe, with high FDG uptake. Surgical resection confirmed the diagnosis of pulmonary cryptococcosis.

Thumbnail

Figure 4
A 74-year-old man with esophageal cancer and multiple areas of ground-glass opacities with FDG uptake in the right lung, consistent with bacterial pneumonia.

Thumbnail

Figure 5
A 42-year-old man with a lobulated pulmonary nodule in the right lower lobe (arrows), indeterminate on CT. PET/CT was performed and showed increased metabolic activity (arrow) in the lung nodule, which was surgically resected and was found to be consistent with pulmonary meningioma.

Thumbnail

Figure 6
A 81-year-old man with an occupational history of asbestos exposure. PET/CT images demonstrate high metabolic activity in the left lower lobes, especially in the cortical regions. CT images depict interstitial lung abnormalities, with ground-glass opacities, reticulation, and mild bronchiolectasis.

Thumbnail

Figure 7
A 78-year-old woman submitted to PET/CT for the staging of a cervical carcinoma, with increased FDG uptake in bilateral subscapular masses (arrows), consistent with elastofibroma dorsi.

Thumbnail

Figure 8
Postoperative PET/CT of a patient with history of cardiac tumor. Note the diffuse FDG uptake in the sternum, consistent with inflammatory changes induced by the surgical procedure (arrows). Also note the increased metabolic activity in areas of brown fat in the supraclavicular and paravertebral regions (dashed arrows).

Thumbnail

Figure 9
A 64-year-old woman submitted to PET/CT for the restaging of lung cancer. Multiple foci of FDG uptake are seen in the right pleura (arrows), consistent with an inflammatory process induced by pleurodesis. A careful analysis of CT images demonstrates the high-attenuation pleural thickening, characteristic of pleurodesis.

Thumbnail

Figure 10
A 41-year-old woman with a history of Hodgkin lymphoma and paramediastinal opacities with FDG uptake (arrows), consistent with inflammatory lesions induced by radiation therapy.

Thumbnail

Figure 11
A 63-year-old male, current smoker, with a ground-glass nodule in the right lung (arrow), which had consistently increased in size over the years. PET/CT was performed and was negative. Surgical resection confirmed the diagnosis of adenocarcinoma in situ (formerly known as bronchoalveolar carcinoma). PET/CT is limited for these conditions and should not be used for small nodules with groundglass attenuation, due to the high pretest probability of false-negative results.

Thumbnail

Figure 12
A 57-year-old woman with breast cancer and focal FDG uptake in a left axillary lymph node (arrow). That uptake is consistent with extravasation of FDG in the left arm, draining to the ipsilateral axillary region.

Thumbnail

Figure 13
A 78-year-old man with a pacemaker in his left hemithorax (arrow). A PET attenuation-corrected image shows FDG uptake in the left hemithorax, consistent with an artifact induced by attenuation correction. In cases of uncertainty, the non-attenuation-corrected image can be used in order to avoid misinterpretation.

Figure 1 Causes of physiological FDG uptake in the thorax.A: A 6-year-old boy, with normal metabolic activity in the thymus. The strategy for differentiating between focal uptake in the anterior mediastinum and a lesion is to look at the normal aspect of the thymus on CT images. B: A 56-year-old man with lung cancer and a forceful cough during the PET/CT examination. FDG PET/CT shows increased metabolic activity in the thoracic muscles, due to vigorous coughing. C: A 31-year-old lactating woman, with normal FDG uptake in the breast. Lactation induces higher metabolic activity in the breasts, which should not be interpreted as disease. D: A 28-year-old man with testicular cancer. Multiple areas of FDG uptake in the supraclavicular regions and in the upper mediastinum, consistent with increased metabolic activity in brown fat, which regulates body weight and temperature and can be activated by satiety or cold environments.

Figure 2 A 57-year-old female with cough, fever, and multiple centrilobular pulmonary nodules in the superior segment of the left lower lobe (arrows). PET/CT was performed and showed increased FDG uptake (arrow) in the lung nodules. A CT-guided pulmonary biopsy confirmed the diagnosis of pulmonary tuberculosis.

Figure 3 A 57-year-old man, current smoker, with non-Hodgkin lymphoma and a spiculated pulmonary nodule (arrows) in the left upper lobe, with high FDG uptake. Surgical resection confirmed the diagnosis of pulmonary cryptococcosis.

Figure 4 A 74-year-old man with esophageal cancer and multiple areas of ground-glass opacities with FDG uptake in the right lung, consistent with bacterial pneumonia.

Figure 5 A 42-year-old man with a lobulated pulmonary nodule in the right lower lobe (arrows), indeterminate on CT. PET/CT was performed and showed increased metabolic activity (arrow) in the lung nodule, which was surgically resected and was found to be consistent with pulmonary meningioma.

Figure 6 A 81-year-old man with an occupational history of asbestos exposure. PET/CT images demonstrate high metabolic activity in the left lower lobes, especially in the cortical regions. CT images depict interstitial lung abnormalities, with ground-glass opacities, reticulation, and mild bronchiolectasis.

Figure 7 A 78-year-old woman submitted to PET/CT for the staging of a cervical carcinoma, with increased FDG uptake in bilateral subscapular masses (arrows), consistent with elastofibroma dorsi.

Figure 8 Postoperative PET/CT of a patient with history of cardiac tumor. Note the diffuse FDG uptake in the sternum, consistent with inflammatory changes induced by the surgical procedure (arrows). Also note the increased metabolic activity in areas of brown fat in the supraclavicular and paravertebral regions (dashed arrows).

Figure 9 A 64-year-old woman submitted to PET/CT for the restaging of lung cancer. Multiple foci of FDG uptake are seen in the right pleura (arrows), consistent with an inflammatory process induced by pleurodesis. A careful analysis of CT images demonstrates the high-attenuation pleural thickening, characteristic of pleurodesis.

Figure 10 A 41-year-old woman with a history of Hodgkin lymphoma and paramediastinal opacities with FDG uptake (arrows), consistent with inflammatory lesions induced by radiation therapy.

Figure 11 A 63-year-old male, current smoker, with a ground-glass nodule in the right lung (arrow), which had consistently increased in size over the years. PET/CT was performed and was negative. Surgical resection confirmed the diagnosis of adenocarcinoma in situ (formerly known as bronchoalveolar carcinoma). PET/CT is limited for these conditions and should not be used for small nodules with groundglass attenuation, due to the high pretest probability of false-negative results.

Figure 12 A 57-year-old woman with breast cancer and focal FDG uptake in a left axillary lymph node (arrow). That uptake is consistent with extravasation of FDG in the left arm, draining to the ipsilateral axillary region.

Figure 13 A 78-year-old man with a pacemaker in his left hemithorax (arrow). A PET attenuation-corrected image shows FDG uptake in the left hemithorax, consistent with an artifact induced by attenuation correction. In cases of uncertainty, the non-attenuation-corrected image can be used in order to avoid misinterpretation.

Como citar

copiar

Publicação do Colégio Brasileiro de Radiologia e Diagnóstico por Imagem Av. Paulista, 37 - 7º andar - conjunto 71, 01311-902 - São Paulo - SP, Tel.: +55 11 3372-4541, Fax: 3285-1690, Fax: +55 11 3285-1690 - São Paulo - SP - Brazil
E-mail: radiologiabrasileira@cbr.org.br

Acompanhe os números deste periódico no seu leitor de RSS

Versão para download de PDF

PDF

Inglês

Versões e tradução automática

Versão original do texto

English

Tradução automática

Google Translator
Microsoft Translator

Como citar

RIS

BIBTEX

Outros formatos de citação e exportação:

SciELO - Scientific Electronic Library Online
Rua Dr. Diogo de Faria, 1087 – 9º andar – Vila Clementino 04037-003 São Paulo/SP - Brasil
E-mail: scielo@scielo.org

Leia a Declaração de Acesso Aberto

Métricas

Mensagem

[1] Mailing address: Dr. Gustavo de Souza Portes Meirelles, Rua Cincinato Braga, 282, Bela Vista, São Paulo, SP, Brazil, 01333-010. E-mail: gustavo.meirelles@grupofleury.com.br