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PET/CT imaging in lung cancer: indications and findings.

Hochhegger B, Alves GR, Irion KL, Fritscher CC, Fritscher LG, Concatto NH, Marchiori E - J Bras Pneumol (2015 May-Jun)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.

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.

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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.
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f02: 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.

Mentions: Despite producing promising results, PET/CT imaging has been shown to have a relatively low positive predictive value (PPV). Especially in virtue of that, the method has not yet proven to be a reliable replacement for CT or MRI imaging as a routine procedure; nor can positive PET/CT findings, such as those shown in Figure 2, eliminate the need for invasive procedures (mediastinoscopy sampling, followed by histological analysis). It is worth noting that PPVs always depend on population characteristics; for example, endemic granulomatous diseases and occupational-related lung disorders can lower the PPV of PET/CT. However, in most patients without findings indicative of malignancy, PET/CT can safely obviate sometimes harmful interventions. Nevertheless, PET/CT can occasionally yield false-negative results in cases of low-growth lesions (either primary or metastatic). Some authors refer to this exceptional situation as "minimal N2", taking into account the better prognosis of such cases in comparison with that of other N2 tumors. In addition, the proximity of various mediastinal structures can occasionally diminish tracer uptake in centrally located malignant nodes.(8) However, it should be borne in mind that PET/CT could be crucial in evaluating nodal sites that are typically inaccessible to mediastinoscopy, such as the aortopulmonary window, anterior mediastinum, and posterior subcarinal nodes. In such cases, it might be advisable to conduct further evaluations by following PET/CT with mediastinotomy, transbronchial biopsy, or endoscopic ultrasound-guided fine needle aspiration.


PET/CT imaging in lung cancer: indications and findings.

Hochhegger B, Alves GR, Irion KL, Fritscher CC, Fritscher LG, Concatto NH, Marchiori E - J Bras Pneumol (2015 May-Jun)

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.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541763&req=5

f02: 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.
Mentions: Despite producing promising results, PET/CT imaging has been shown to have a relatively low positive predictive value (PPV). Especially in virtue of that, the method has not yet proven to be a reliable replacement for CT or MRI imaging as a routine procedure; nor can positive PET/CT findings, such as those shown in Figure 2, eliminate the need for invasive procedures (mediastinoscopy sampling, followed by histological analysis). It is worth noting that PPVs always depend on population characteristics; for example, endemic granulomatous diseases and occupational-related lung disorders can lower the PPV of PET/CT. However, in most patients without findings indicative of malignancy, PET/CT can safely obviate sometimes harmful interventions. Nevertheless, PET/CT can occasionally yield false-negative results in cases of low-growth lesions (either primary or metastatic). Some authors refer to this exceptional situation as "minimal N2", taking into account the better prognosis of such cases in comparison with that of other N2 tumors. In addition, the proximity of various mediastinal structures can occasionally diminish tracer uptake in centrally located malignant nodes.(8) However, it should be borne in mind that PET/CT could be crucial in evaluating nodal sites that are typically inaccessible to mediastinoscopy, such as the aortopulmonary window, anterior mediastinum, and posterior subcarinal nodes. In such cases, it might be advisable to conduct further evaluations by following PET/CT with mediastinotomy, transbronchial biopsy, or endoscopic ultrasound-guided fine needle aspiration.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.

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.

Show MeSH
Related in: MedlinePlus