PET/CT imaging in lung cancer: indications and findings

Abstract

The use of PET/CT imaging in the work-up and management of patients with lung cancer has greatly increased in recent decades. The ability to combine functional and anatomical information has equipped PET/CT to look into various aspects of lung cancer, allowing more precise disease staging and providing useful data during the characterization of indeterminate pulmonary nodules. In addition, the accuracy of PET/CT has been shown to be greater than is that of conventional modalities in some scenarios, making PET/CT a valuable noninvasive method for the investigation of lung cancer. However, the interpretation of PET/CT findings presents numerous pitfalls and potential confounders. Therefore, it is imperative for pulmonologists and radiologists to familiarize themselves with the most relevant indications for and limitations of PET/CT, seeking to protect their patients from unnecessary radiation exposure and inappropriate treatment. This review article aimed to summarize the basic principles, indications, cancer staging considerations, and future applications related to the use of PET/CT in lung cancer.

Figure 1.. Thoracic PET/CT scans (left) and a PET scan (right), which were performed for the staging of a 57-year-old female patient diagnosed with non-small cell lung cancer. By combining anatomical details with functional data, PET/CT allows more reliable detection of mediastinal and ipsilateral metastatic disease.

Figure 2.. PET/CT axial scan of a 55-year-old male patient, showing two slightly enlarged supraclavicular lymph nodes, which were suspected of malignancy given their hypermetabolic character and location. Subsequent specimen analyses confirmed the presence of metastatic disease.

Figure 3.. PET/CT assessment allowing the diagnosis of bone metastases (A) and adrenal metastases (B) in a 79-year-old male patient with non-small cell lung cancer. Although such lesions were suggested by PET alone (C), their precise location and delineation could not be determined without the addition of CT. J Bras

Figure 4.. PET/CT images of a 60-year-old male patient diagnosed with non-small cell lung cancer and undergoing radiotherapy. Although a large mass in the right upper lobe was detected on chest CT imaging (A), the differentiation between the tumor and normal surrounding structures would not have been feasible without the aid of PET/CT (B).

Figure 5.. PET/CT scan of the chest, revealing numerous areas of high 18F-fluorodeoxyglucose uptake in a 72-year-old male patient with osteoarthritis. In this case, the greater uptake arose from the abnormal inflammatory status, which led to higher glucose consumption.

Figura 1.. PET/TC (esquerda) e PET (direita) torácicas realizadas para estadiamento de paciente do sexo feminino, de 57 anos de idade, com diagnóstico de câncer de pulmão de células não pequenas. Ao combinar detalhes anatômicos com dados funcionais, a PET/TC permite a detecção mais confiável de doença metastática mediastinal e ipsilateral.

Figura 2.. PET/TC axial de paciente do sexo masculino, de 55 anos de idade, mostrando dois linfonodos supraclaviculares ligeiramente aumentados, com suspeição de malignidade por sua característica hipermetabólica e localização. Análises amostrais posteriores confirmaram a presença de doença metastática.

Figura 3.. Imagens de PET/TC que permitiram o diagnóstico de metástases ósseas (A) e metástases adrenais (B) em paciente do sexo masculino, de 79 anos de idade, com câncer de pulmão de células não pequenas. Embora essas lesões tenham sido sugeridas pela PET isoladamente (C), não foi possível determinar sua exata localização e delineamento sem a adição da TC.

Figura 4.. PET/TC de paciente do sexo masculino, de 60 anos de idade, com diagnóstico de câncer de pulmão de células não pequenas e recebendo radioterapia. Apesar da detecção de uma grande massa no lobo superior direito na TC de tórax (A), a diferenciação entre o tumor e as estruturas normais circundantes não teria sido viável sem o auxílio da PET/TC (B).

Figura 5.. PET/TC de tórax revelando inúmeras áreas de captação de 18F-fluordesoxiglicose em paciente do sexo masculino, de 72 anos de idade, com osteoartrite. Neste caso, a maior captação deu-se em razão do estado inflamatório anormal, que levou a um maior consumo de glicose.