Evaluation of pleural diseases with FDG-PET imaging: preliminary report

Pleural effusion guidelines from ICS and NCCP Section 1: Basic principles, laboratory tests and pleural procedures

Pleural effusion is a common problem in our country, and most of these patients need invasive tests as they can't be evaluated by blood tests alone. The simplest of them is diagnostic pleural aspiration, and diagnostic techniques such as medical thoracoscopy are being performed more frequently than ever before. However, most physicians in India treat pleural effusion empirically, leading to delays in diagnosis, misdiagnosis and complications from wrong treatments. This situation must change, and the adoption of evidence-based protocols is urgently needed. Furthermore, the spectrum of pleural disease in India is different from that in the West, and yet Western guidelines and algorithms are used by Indian physicians. Therefore, India-specific consensus guidelines are needed. To fulfil this need, the Indian Chest Society and the National College of Chest Physicians; the premier societies for pulmonary physicians came together to create this National guideline. This document aims to provide evidence based recommendations on basic principles, initial assessment, diagnostic modalities and management of pleural effusions.

A PET-CT score for discriminating malignant from benign pleural effusions

BACKGROUND AND OBJECTIVES

The results of previous PET-CT studies are contradictory for discriminating malignant from benign pleural effusions. We purpose to develop a PET-CT score for differentiating between benign and malignant effusions.

PATIENTS AND METHODS

We conducted a prospective study of consecutive patients with pleural effusions undergoing PET-CT from October 2013 to October 2019 (referral cohort). PET-CT scan features evaluated using the SUV were: linear thickening; nodular thickening; nodules; masses; circumferential thickening; mediastinal and fissural pleural involvement; intrathoracic lymph nodes; pleural loculation; inflammatory consolidation; pleural calcification; cardiomegaly; pericardial effusion; bilateral effusion; lung mass; liver metastasis and other extra-pleural malignancy. The results were validated in an independent prospective cohort from November 2019 to June 2021.

RESULTS

One hundred and ninety-nine patients were enrolled in the referral cohort (91 with malignant effusions and 108 benign). The most useful parameters for the development of a PET-CT score were: nodular pleural thickening, pleural nodules with SUV>7.5, lung mass or extra pleural malignancy (10 points each), mammary lymph node with SUV>4.5 (5 points) and cardiomegaly (-1 point). With a cut-off value of >9 points in the referral cohort, the score established the diagnosis of malignant pleural effusion with sensitivity 87.9%, specificity 90.7%, positive predictive value 88.9%, negative predictive value 89.9%, positive likelihood ratio 7.81 and negative likelihood ratio 0.106. These results were validated in an independent prospective cohort of 75 patients.

CONCLUSIONS

PET-CT score was shown to provide relevant information for the identification of malignant pleural effusion.

The contribution of PET/CT to the differentiation of benign and malignant pleural effusion in patients with ovarian carcinoma

OBJECTIVE

The present study investigates the ability of non-invasive contribution of positron emission tomography (PET)/computed tomography (CT) to distinguish between benign pleural effusions (BPE) and malignant pleural effusions (MPE) in patients diagnosed with ovarian carcinoma (OC).

MATERIAL AND METHODS

Included in the study were 32 OC patients with a PE diagnosis. The cases with BPE and MPE were compared in terms of the PE maximum standardized uptake value (SUVmax), PE SUVmax/mean standardized uptake (SUVmean) value of the mediastinal blood pool (TBRp), the presence of pleural thickening, the presence of supradiaphragmatic lymph node, unilateral or bilateral PE, pleural effusion diameter, patient age and CA125 value.

RESULTS

The mean age of the 32 patients was 57±2.8 years. TBRp>1.1, pleural thickening and supradiaphragmatic lymph node were observed significantly more frequently in the MPE than the BPE cases. While no pleural nodules were detected in patients with BPE, they were present in 7 of the patients with MPE. The rates of distinction between the MPE and BPE cases were as follows: the sensitivity of the TBRp value was 95.2% and specificity was 72.7%; the sensitivity of pleural thickness was 80.9% and specificity was 81.8%; the sensitivity of supradiaphragmatic lymph node was 38% and specificity was 90.9%; and the sensitivity of the pleural nodule was 33.3% and specificity was 100%. There were no significant differences between two groups in any other factors.

CONCLUSIONS

Pleural thickening and TBRp values ascertained through PET/CT may aid the distinction between MPE-BPE, especially in patients with advanced stage OC with a poor general condition, or those who cannot undergo surgery.

Positron emission tomography-computed tomography (PET-CT) in suspected malignant pleural effusion. An updated systematic review and meta-analysis

The role of PET and integrated PET-CT in the diagnostic workup of suspected malignant pleural effusions is unknown. Earlier systematic reviews (published 2014 and 2015) both included pleural pathology without effusion, and reached contradictory conclusions. Five studies have been published since the latest review. This systematic review and meta-analysis aims to summarise the evidence of PET and integrated PET-CT in predicting pleural malignancy in patients suspected of having malignant pleural effusions. A meta-analysis based on a systematic literature search in Cochrane Library, Medline, EMBASE and Clinicaltrials.gov was performed. Diagnostic studies evaluating the performance of PET or PET-CT in patients with suspected malignant pleural effusion, using pleural fluid cytology or histopathology as the reference test, and presenting sufficient data for constructing a 2x2 table were included. The quality of the studies was assessed by the Quality Assessment of Diagnostic Accuracy Studies-2 score. Subgroup analyses on image modality, interpretation method and known malignancy status pre index-test application were planned. Seven studies with low risk of bias were included. The pooled ability to separate benign from malignant effusions varied with image modality, interpretation method and known malignancy status pre index-test application. In studies using PET-CT, visual/qualitative image analysis was superior to semi-quantitative with positive (LR + ) and negative likelihood ratio (LR-) of 9.9 (4.5-15.3) respectively 0.1 (0.1-0.2). There was considerable heterogeneity among studies. In conclusion, visual/qualitative image analysis of integrated PET-CT seems to add relevant information in the work-up of suspected malignant pleural effusions with LR + and LR- close to rigorous pre-set cut-offs of > 10 and < 0.1. However, the quality of evidence was low due to inter-study heterogeneity, and inability to assess meta-bias. Clinical Trial Registration: The protocol was uploaded to the PROSPERO database (CRD42020213319) on the 13th of October 2020.

Predicting the nature of pleural effusion in patients with lung adenocarcinoma based on 18F-FDG PET/CT

Background

This study aims to establish a predictive model on the basis of ¹⁸F-FDG PET/CT for diagnosing the nature of pleural effusion (PE) in patients with lung adenocarcinoma.

Methods

Lung adenocarcinoma patients with PE who underwent ¹⁸F-FDG PET/CT were collected and divided into training and test cohorts. PET/CT parameters and clinical information in the training cohort were collected to estimate the independent predictive factors of malignant pleural effusion (MPE) and to establish a predictive model. This model was then applied to the test cohort to evaluate the diagnostic efficacy.

Results

A total of 413 lung adenocarcinoma patients with PE were enrolled in this study, including 245 patients with MPE and 168 patients with benign PE (BPE). The patients were divided into training (289 patients) and test (124 patients) cohorts. CEA, SUVmax of tumor and attachment to the pleura, obstructive atelectasis or pneumonia, SUVmax of pleura, and SUVmax of PE were identified as independent significant factors of MPE and were used to construct a predictive model, which was graphically represented as a nomogram. This predictive model showed good discrimination with the area under the curve (AUC) of 0.970 (95% CI 0.954–0.986) and good calibration. Application of the nomogram in the test cohort still gave good discrimination with AUC of 0.979 (95% CI 0.961–0.998) and good calibration. Decision curve analysis demonstrated that this nomogram was clinically useful.

Conclusions

Our predictive model based on ¹⁸F-FDG PET/CT showed good diagnostic performance for PE, which was helpful to differentiate MPE from BPE in patients with lung adenocarcinoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13550-021-00850-2.

Development and validation of the PET-CT score for diagnosis of malignant pleural effusion

Purpose

Although some parameters of positron emission tomography with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) and computed tomography (PET-CT) are somehow helpful in differentiating malignant pleural effusion (MPE) from benign effusions, no individual parameter offers sufficient evidence for its implementation in the clinical practice. The aim of this study was to establish the diagnostic accuracy of a scoring system based on PET-CT (the PET-CT score) in diagnosing MPE.

Methods

One prospective derivation cohort of patients with pleural effusions (84 malignant and 115 benign) was used to develop the PET-CT score for the differential diagnosis of malignant pleural effusion. The PET-CT score was then validated in another independent prospective cohort (n = 74).

Results

The PET-CT parameters developed for discriminating MPE included unilateral lung nodules and/or masses with increased ¹⁸F-FDG uptake (3 points); extrapulmonary malignancies (3 points); pleural thickening with increased ¹⁸F-FDG uptake (2 points); multiple nodules or masses (uni- or bilateral lungs) with increased ¹⁸F-FDG uptake (1 point); and increased pleural effusion ¹⁸F-FDG uptake (1 point). With a cut-off value of 4 points in the derivation cohort, the area under the curve, sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of the PET-CT score to diagnose MPE were 0.949 (95% CI: 0.908–0.975), 83.3% (73.6%–90.6%), 92.2% (85.7%–96.4%), 10.7 (5.6–20.1), and 0.2 (0.1–0.3), respectively.

Conclusions

A simple-to-use PET-CT score that uses PET-CT parameters was developed and validated. The PET-CT score can help physicians to differentiate MPE from benign pleural effusions.

Electronic supplementary material

The online version of this article (10.1007/s00259-019-04287-7) contains supplementary material, which is available to authorized users.

Present and future roles of FDG-PET/CT imaging in the management of malignant pleural mesothelioma

Positron emission tomography/computed tomography (PET/CT) integrated with 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)F-FDG) has emerged as a powerful tool for combined metabolic and anatomic evaluations in clinical oncologic imaging. This review discusses the utility of (18)F-FDG PET/CT as a tool to manage patients with malignant pleural mesothelioma. We discuss different stages of patient management in malignant pleural mesothelioma, including diagnosis, initial staging, therapy planning, early treatment response assessment, re-staging, and prognosis.

Accuracy of fluorodeoxyglucose-PET imaging for differentiating benign from malignant pleural effusions: a meta-analysis

BACKGROUND

The role of fluorodeoxyglucose (FDG)-PET imaging for diagnosing malignant pleural effusions is not well defined. The aim of this study was to summarize the evidence for its use in ruling in or out the malignant origin of a pleural effusion or thickening.

METHODS

A meta-analysis was conducted of diagnostic accuracy studies published in the Cochrane Library, PubMed, and Embase (inception to June 2013) without language restrictions. Two investigators selected studies that had evaluated the performance of FDG-PET imaging in patients with pleural effusions or thickening, using pleural cytopathology or histopathology as the reference standard for malignancy. Subgroup analyses were conducted according to FDG-PET imaging interpretation (qualitative or semiquantitative), PET imaging equipment (PET vs integrated PET-CT imaging), and/or target population (known lung cancer or malignant pleural mesothelioma). Study quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2. We used a bivariate random-effects model for the analysis and pooling of diagnostic performance measures across studies.

RESULTS

Fourteen non-high risk of bias studies, comprising 407 patients with malignant and 232 with benign pleural conditions, met the inclusion criteria. Semiquantitative PET imaging readings had a significantly lower sensitivity for diagnosing malignant effusions than visual assessments (82% vs 91%; P = .026). The pooled test characteristics of integrated PET-CT imaging systems using semiquantitative interpretations for identifying malignant effusions were: sensitivity, 81%; specificity, 74%; positive likelihood ratio (LR), 3.22; negative LR, 0.26; and area under the curve, 0.838. Resultant data were heterogeneous, and spectrum bias should be considered when appraising FDG-PET imaging operating characteristics.

CONCLUSIONS

The moderate accuracy of PET-CT imaging using semiquantitative readings precludes its routine recommendation for discriminating malignant from benign pleural effusions.

Diagnostic accuracy of 18F-FDG-PET and PET/CT in the differential diagnosis between malignant and benign pleural lesions: a systematic review and meta-analysis

RATIONALE AND OBJECTIVES

To systematically review and meta-analyze published data about the diagnostic accuracy of fluorine-18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and PET/computed tomography (CT) in the differential diagnosis between malignant and benign pleural lesions.

METHODS AND MATERIALS

A comprehensive literature search of studies published through June 2013 regarding the diagnostic performance of (18)F-FDG-PET and PET/CT in the differential diagnosis of pleural lesions was carried out. All retrieved studies were reviewed and qualitatively analyzed. Pooled sensitivity, specificity, positive and negative likelihood ratio (LR+ and LR-) and diagnostic odds ratio (DOR) of (18)F-FDG-PET or PET/CT in the differential diagnosis of pleural lesions on a per-patient-based analysis were calculated. The area under the summary receiver operating characteristic curve (AUC) was calculated to measure the accuracy of these methods. Subanalyses considering device used (PET or PET/CT) were performed.

RESULTS

Sixteen studies including 745 patients were included in the systematic review. The meta-analysis of 11 selected studies provided the following results: sensitivity 95% (95% confidence interval [95%CI]: 92-97%), specificity 82% (95%CI: 76-88%), LR+ 5.3 (95%CI: 2.4-11.8), LR- 0.09 (95%CI: 0.05-0.14), DOR 74 (95%CI: 34-161). The AUC was 0.95. No significant improvement of the diagnostic accuracy considering PET/CT studies only was found.

CONCLUSIONS

(18)F-FDG-PET and PET/CT demonstrated to be accurate diagnostic imaging methods in the differential diagnosis between malignant and benign pleural lesions; nevertheless, possible sources of false-negative and false-positive results should be kept in mind.

CD147 immunohistochemistry discriminates between reactive mesothelial cells and malignant mesothelioma

Malignant mesothelioma (MM) is a rare form of cancer. Its histopathological diagnosis is very difficult, as it exhibits a number of different appearances that can be misinterpreted as metastatic invasion or atypical hyperplasia. Thus, there is an urgent need to identify adequate markers to distinguish between benign and malignant cells, allowing the implementation of appropriate therapies and, possibly, specific directed therapies. MM, like other tumors, show an increase in glucose uptake, due to high rates of glycolysis, inducing an intracellular overload of acids. In this context, monocarboxylate transporters (MCTs) emerge as important players, by mediating the transmembranar co-transport of lactate with a proton, thereby, regulating pH and allowing continuous glycolysis. Importantly, proper MCT expression and activity depend on its co-expression with a chaperone, CD147, which is associated with poor prognosis in cancer. Twenty-two samples including reactive mesothelial cells, MM, and atypical mesothelial hyperplasias were evaluated for immunoexpression of MCT1, MCT4, and CD147. Expression of these proteins was compared with GLUT1 as a new promising marker for MM. Although MCT isoforms were not differentially expressed in the two types of cytological specimens, CD147, as GLUT1, was almost exclusively expressed in MM. Both MCT1 and MCT4 are not able to discriminate between mesothelial reactive cells and mesothelial malignant cells, while CD147 was able to distinguish these two proliferations. If confirmed, besides being a good marker for identification of MM, CD147 may also be a target for therapeutical strategies in this rare type of tumor.

FDG PET/CT Response Evaluation in Malignant Pleural Mesothelioma Patients Treated with Talc Pleurodesis and Chemotherapy

PURPOSE

Talc pleurodesis (TP) is employed worldwide for the management of persistent pneumothorax or pleural effusion, particularly of malignant origin. However, there are very little available data on (18)F-fluorodeoxyglucose positron-emission tomography/computed tomography ((18)F FDG PET/CT) response evaluation in malignant pleural mesothelioma (MPM) patients treated with TP and chemotherapy.

METHODS

Patients with histologically confirmed MPM underwent TP and FDG PET/CT staging and restaging after 3-4 courses of chemotherapy. All patients fasted and received a dose of 5.18 MBq (18)F-FDG per kilogram of body weight. Whole-body emission scans were acquired with and without Ordered Subset Expectation Maximization (OSEM) iterative reconstruction algorithm.

RESULTS

From January 2004 to March 2010, 8 patients with biopsy confirmed MPM (7 epithelial, 1 biphasic), with a median age of 65 years (range: 54-77), were evaluated. Median follow-up was 31 months (range: 4-44). After TP treatment, there was a mean interval of 14 days (range: 9-22) and 125 days (range: 76-162) between FDG PET/CT staging and restaging. According to modified RECIST and EORTC criteria, there was a concordance between the radiologic and metabolic SUVmean and SUVmax responses in 6 (75%) and 3 (37.5%) patients, respectively.

CONCLUSION

TP produces an increased FDG PET uptake which may interfere with the post-chemotherapy disease evaluation. In our case series, the metabolic response measured by SUVmean seems to be in better agreement with the radiologic response compared to the SUVmax.

A newly developed pericardial tuberculoma during antituberculous therapy

Tuberculosis generally affects the respiratory tract. In developing nations, the pericardium is the most common location of extrapulmonary tuberculosis; however, tuberculous pericarditis rarely appears as a localized mass or tuberculoma. We present here a case of a 62-year-old woman with pericardial tuberculoma. She had a history of effusive tuberculous pericarditis and drainage. Because she had taken regular medication over a period of six months, the pericardial mass with an adjacent lung nodule newly detected on the chest radiogram was initially suspected of being invasive lung cancer. Prior to pathologic confirmation, precise information from imaging tests, including computed tomography, magnetic resonance imaging, and positron emission tomography-computed tomography are helpful when making decisions regarding which methods should be used for surgical approach and treatment. Through imaging, our case showed typical features of pericardial tuberculoma and a favorable clinical course after two months with a change in antituberculous therapy.

Multimodality Imaging Review of Malignant Pleural Mesothelioma Diagnosis and Staging

Early diagnosis and accurate disease staging in patients with malignant pleural mesothelioma (MPM) are essential in classifying such patients into prognostic subgroups to allow delivery of stage-specific therapies. This review addresses the current status of multimodality imaging in the diagnosis and staging of MPM. Clinical, research, and future directions in computed tomography (CT), magnetic resonance imaging, and PET/CT diagnosis and staging of MPM are discussed, including the use of novel PET probes. The article concludes with important take-home messages summarized as the pearls and pitfalls of each diagnostic modality in the diagnosis and staging of patients with MPM.

Predictive value of F-18 FDG PET/CT for malignant pleural effusion in non-small cell lung cancer patients

BACKGROUND

The purpose of this study was to evaluate the accuracy of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) imaging in the detection of malignant pleural effusion and pleural metastasis in patients with non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

We analyzed F-18 FDG PET/CT images of 33 lung cancer patients with pleural effusion. We used 2 categorical parameters to differentiate malignant from benign pleural effusion: i) quantitative parameters using maximum standardized uptake value (SUVmax of effusion and pleura, and the following ratios: lesion to aorta (L/Ao), to cerebellum (L/Cbl), to liver (L/Liv), to nonlesion (L/NL), and to primary lung cancer (L/Prim)) and ii) various parameters determined by PET and CT scans (uptake at the pleural region, Hounsfield unit, size, and morphology of any solid abnormality).

RESULTS

Malignant pleural effusions showed significantly higher L/Prim values than benign pleural effusions. The presence of pleural abnormality on CT and pleural region uptake on PET images were found to be significantly more frequent in cases of malignant pleural disease. These parameters could differentiate malignant and benign pleural effusion according to receiver operating characteristic (ROC) analyses. There were no statistical differences between L/Prim, pleural abnormality on CT, and pleural region uptake on PET images. Abnormal pleural region uptake on PET images was the most accurate parameter identifying malignant pleural effusion by logistic regression analysis.

CONCLUSIONS

Our results suggest that F-18 FDG PET/CT can be used as a reliable and noninvasive method for the differentiation of malignant and benign pleural disease in patients with NSCLC.

[What is the role of FDG-PET in thoracic oncology in 2010?]

18F-Fluorodeoxyglucose-Positron Emission Tomography (FGD-PET) has been considered to have a major impact on the management of lung malignancies since the beginning of this century. Its value has been demonstrated by many publications, meta-analysis and European/American/Japanese recommendations. PET combined with computed tomography has provided useful information regarding the diagnosis and staging of lung cancer and allows for the delivery of adaptive radiotherapy. In its more common uses, PET has been shown to be cost-effective. With the widespread use of new radiotracers, PET will play an increasing role in the evaluation of response to treatment.

Contribution of positron emission tomography in pleural disease

INTRODUCTION

Positron emission tomography (PET) now plays a clear role in oncology, especially in chest tumours. We discuss the value of metabolic imaging in characterising pleural pathology in the light of our own experience and review the literature.

BACKGROUND

PET is particularly useful in characterising malignant pleural pathologies and is a factor of prognosis in mesothelioma. Metabolic imaging also provides clinical information for staging lung cancer, in researching the primary tumour in metastatic pleurisy and in monitoring chronic or recurrent pleural pathologies.

CONCLUSIONS

PET should therefore be considered as a useful tool in the diagnosis of liquid or solid pleural pathologies.

Imaging of pleural masses: which to choose?

The differential diagnosis of pleural masses is limited. Asbestos-related disease and invasive bronchogenic carcinoma make up the majority of cases. The diagnostic yield of biopsies is low, and invasive procedures are often required to achieve diagnosis. A variety of imaging techniques are available to help differentiate between benign and malignant disease to help discern which patients to biopsy. While computed tomography has a relatively good sensitivity and specificity, magnetic resonance imaging (MRI) and positron emission tomography (PET) both appear to have higher accuracy. MRI has the added benefit of being an excellent aid in determining surgical resectability of tumors. MRI and PET are limited, however, by their cost and availability in certain regions.

La tomographie par émission de positons au 18fluorodésoxyglucose (18FDG-TEP) dans la prise en charge du cancer bronchique non à petites cellules en 2006

Technological progress and numerous published studies allow to estimate the best place of the 18F-fluorodeoxyglucose positron emission tomography, a real functional metabolic imagery, in the clinical and therapeutic strategy of non small cell lung cancers.

18F-FDG PET imaging in assessing exudative pleural effusions

BACKGROUND

This study evaluates the accuracy of [F]fluorodeoxyglucose positron emission tomography (F-FDG PET) imaging with semi-quantitative analysis for differentiating benign from malignant pleural exudates and for guiding the search for the primary tumour of pleural metastases.

METHODS

Whole-body 18F-FDG PET was performed in 79 patients with exudative pleurisy. Standard uptake values were normalized for body weight, body surface area, lean body mass (SUVbw, SUVbsa, SUVlbm) with and without correction for blood glucose levels. Thoracoscopy was systematically performed to reveal pathological diagnosis.

RESULTS

All SUVs were significantly higher in all malignant pleural diseases (n = 51) than in benign (n = 28) (P < 0.001). Moreover SUVs were greater in the pleural metastases from pulmonary primaries (n = 25) and in mesotheliomas (n = 8) than in extrathoracic primaries (n = 18) (P < 0.01) with no significant difference between lung cancers and mesotheliomas. Receiver operating curve (ROC) analysis between benign and malignant lesions showed areas under the curves that ranged from 0.803 (SUVbsa g) to 0.863 (SUVbw). The cut-off value for SUVbw which gave the best accuracy (82.3%) was 2.2. When comparing thoracic with extrathoracic primaries the highest accuracy (80.4%) was found for a cut-off value of 2.6.

CONCLUSION

Semi-quantitative analysis of 18F-FDG PET imaging helps to differentiate malignant from benign pleural exudates and to distinguish between thoracic or extrathoracic primaries.

[PET in primary pulmonary or pleural cancer]

In our hospital as in many others, primary lung cancer is the most frequent indication for FDG PET. Studies have assessed the clinical utility of this imaging modality in characterizing solitary pulmonary nodules or masses, initial staging, defining tumor volume in radiotherapy and searching for recurrence of or restaging non-small cell carcinoma; studies are currently underway to evaluate its use in early assessment of chemotherapy response. Small cell lung cancer has a high FDG uptake and PET/CT can be useful for rapid staging. False negative results may be due to pure bronchioloalveolar carcinomas and endocrine tumors. FDG-PET will certainly play a more important role in the diagnosis and follow-up of pleural cancers in the future. An unexpected positive FDG PET focus should be considered as a warning, but histological proof should precede any irrevocable decisions.

Imaging of the Patient with Non–Small Cell Lung Cancer

Lung cancer is the most common type of cancer and is the leading cause of cancer deaths in the United States for both men and women. Even though the 5-year survival rate of patients with lung cancer remains dismal at 14% for all cancer stages, treatments are improving and newer agents for lung cancer appear promising. Therefore, an accurate assessment of the extent of disease is critical to determine whether the patient is treated with surgical resection, radiation therapy, chemotherapy, or a combination of these modalities. Radiologic imaging plays an important role in the staging evaluation of the patient; however, radiologists need to be aware that there are also important differences in what each specialist needs from imaging to provide appropriate treatment. This article reviews the role of imaging in patients with non-small cell lung cancer, with an emphasis on the radiologic imaging findings relevant for each specialty.

Imaging of Metastatic Disease to the Thorax

Tumor imaging is at the forefront of radiology technology and is the focus of most cutting edge research. Radiologic applications for imaging of metastases are applied to initial staging, restaging after neoadjuvant therapy, and follow-up surveillance after therapy for tumor recurrence. CT is the routine imaging choice in staging, restaging, and detection of recurrence. Fluorodeoxyglucose-positron emission tomography has evolved as an imaging modality that further improves staging as well as the detection of recurrent and metastatic disease.

Imaging of non-small cell lung cancer

Radiologic evaluation is an important component of the clinical staging evaluation of lung cancer and can greatly influence whether the patient is treated with surgical resection, radiation therapy, chemotherapy, or a combination of these modalities. In addition to staging, the radiologic evaluation of the patient undergoing treatment and subsequent follow-up is important to the clinician for assessing treatment effects and complications. This article discusses the imaging of patients with non-small cell lung cancer and its use in management of these patients.

Evolving role of positron emission tomography in the management of patients with inflammatory and other benign disorders

Fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) has evolved from a research imaging modality assessing brain function in physiologic and pathologic states to a pure clinical necessity. It has been successfully used for diagnosing, staging, and monitoring a variety of malignancies. FDG-PET imaging also is evolving into a powerful imaging modality that can be effectively used for the diagnosis and monitoring of a certain nononcological diseases. PET has been shown to be very useful in the diagnosis of osteomyelitis, painful prostheses, sarcoidosis, fever of unknown etiology, and acquired immunodeficiency syndrome. Based on recent observations, several other disorders, such as environment-induced lung diseases, atherosclerosis, vasculitis, back pain, transplantation, and blood clot, can be successfully assessed with this technique. With the development and the introduction of several new PET radiotracers, it is expected that PET will secure a major role in the management of patients with inflammatory and other benign disorders.

Fluorodeoxyglucose-PET in characterizing solitary pulmonary nodules, assessing pleural diseases, and the initial staging, restaging, therapy planning, and monitoring response of lung cancer

Fluorodeoxyglucose-PET imaging has secured an important role in the assessment and management of a multitude of pulmonary disorders, including solitary pulmonary nodules, lung cancer, and pleural diseases. While conventional imaging modalities such as chest radiography and CT are considered essential in these settings, FDG-PET can provide new information and complement structural imaging techniques in the evaluation of such disorders. In this review, the authors present a growing body of evidence that demonstrates and supports the utility of FDG-PET in the differentiation of benign and malignant pulmonary nodules, the assessment of lung cancer in various stages of disease, and the characterization of pleural diseases. In addition, new developments--such as prospects for potential utility of novel radiotracers and delayed imaging--that can further refine the role of FDG scans in the work-up of lung nodules and cancer and forecast the future place of PET in these common modalities are discussed.

Radiology in pleural disease: State of the art

Diseases of the pleura and pleural space are common and present a significant contribution to the workload of the chest radiologist. The radiology department plays a crucial role in the imaging and management of pleural disease. This review aims to describe and illustrate the appearances of common pleural pathologies on various radiological modalities including plain film, ultrasound, CT, magnetic resonance imaging and positron emission tomography. The review will also address the state-of-the-art techniques used to image pleural disease and discuss image-guided intervention in the management of pleural disease.

Fluorodeoxyglucose Positron Emission Tomography and CT After Talc Pleurodesis

BACKGROUND

Talc pleurodesis is widely performed for the management of persistent pneumothorax or pleural effusion, particularly malignant effusions. However, there are very few data characterizing fluorodeoxyglucose (FDG)-positron emission tomography (PET) and CT findings after treatment.

METHODS

We retrospectively evaluated the FDG-PET and CT studies of nine patients who underwent talc pleurodesis for the treatment of malignant pleural effusions or persistent air leak.

RESULTS

FDG-PET studies were performed on average 22 months after talc pleurodesis, and the mean CT follow-up period was 25 months. There was moderate-to-intense plaque-like or focal nodular-increased FDG uptake in the pleura on PET with mean standardized uptake value of 5.4 (SEM, 1.2; range, 2.0 to 16.3). The FDG uptake was either diffuse (two patients) or focal (seven patients), and most commonly occurred in the posterior costophrenic angles (five patients), followed by the apical regions (three patients), anterior costophrenic angle (one patient), and the anterior chest wall (one patient). On CT, high-density areas of pleural thickening or nodularity (mean, 230 Hounsfield units [HU]; SEM, 23 HU; range, 140 to 380 HU) corresponded to regions of increased FDG uptake. These pleural foci had an average thickness of 1.2 cm and measured up to 8.2 cm (mean, 7.1 cm) in length. Rounded pleural nodules were as large as 3.1 cm (mean, 1.5 cm).

CONCLUSIONS

Talc pleurodesis produces increased FDG uptake on PET and high-density areas of pleural thickening on CT that remain unchanged on serial imaging. When PET detects increased uptake in the pleural space, correlation with CT is recommended to detect the presence of pleural thickening of increased attenuation that suggests talc deposits rather than tumor.

Non-small cell lung cancer: evaluation of pleural abnormalities on CT scans with 18F FDG PET

PURPOSE

To evaluate the accuracy of fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) in differentiation of pleural malignancy and cancer-unrelated pleural disease in patients with non-small cell lung cancer (NSCLC) and pleural abnormalities at computed tomography (CT).

MATERIALS AND METHODS

In 92 patients, pleural abnormalities were detected at contrast material-enhanced thoracic CT, which was performed for newly diagnosed NSCLC (n = 41) or restaging (n = 51). CT findings were negative for pleural malignancy when pleural effusion with attenuation of 10 HU or less and/or rib fractures with no evidence of pathologic fracture were present; findings were indeterminate when pleural effusion with attenuation greater than 10 HU and/or solid pleural abnormalities without osseous destruction of the chest wall were present; and findings were positive if any osseous destruction of the chest wall adjacent to a pleural mass was present. All patients underwent FDG PET. Findings were negative for pleural malignancy if pleural activity was absent, equal to, or less than mediastinal background activity; findings were positive if pleural activity was higher than mediastinal background activity. Reading of CT and FDG PET scans was first performed separately and then was combined. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPP), and accuracy were calculated for CT and FDG PET separately and for CT and FDG PET combined, with cytologic and/or histologic analysis as standard of reference.

RESULTS

In detection of pleural malignancies, CT findings were indeterminate in 65 (71%) patients and true-negative in 27 (29%). Respective sensitivity, specificity, PPV, NPV, and accuracy of FDG PET in detection of pleural malignancies were 100%, 71%, 63%, 100%, and 80%; and those of CT and FDG PET combined, 100%, 76%, 67%, 100%, and 84%.

CONCLUSION

Findings suggest that a negative FDG PET scan for indeterminate pleural abnormalities at CT indicates a benign character, while positive findings on an FDG PET scan are sensitive for malignancy.

Evaluation of Pleural Disease With 18-Fluorodeoxyglucose Positron Emission Tomography Imaging

STUDY OBJECTIVES

To study the ability of positron emission tomography (PET) using 18-fluorodeoxyglucose (FDG) to distinguish between benign and malignant disease in exudative pleural effusions and pleural thickening.

DESIGN

Prospective study of 98 consecutive patients presenting with either pleural thickening or an exudative pleural effusion.

SETTING

Department of pulmonary medicine of a university hospital.

METHODS

FDG-PET was performed on each subject before invasive procedures were used to determine the etiologic diagnosis. FDG-PET data were analyzed by visual interpretation.

RESULTS

Sixty-three of 98 patients were found to have malignant pleural disease after histologic analysis. Sixty-one of 63 patients with histologically confirmed malignant disease showed FDG uptake within the area of pleural thickening. Uptake was graded as intense in 51 cases and moderate in 10 cases. Only two patients with malignant pleural disease did not show increased FDG uptake. FDG-PET imaging showed an absence of FDG uptake, and correctly classified 31 of 35 benign lesions. For the remaining four lesions, intense FDG uptake was seen in one case of parapneumonic effusion, while moderate and localized uptake was observed in one parapneumonic, one tuberculous, and one uremic pleurisy. The sensitivity of the method to identify malignancy was 96.8% with a negative predictive value of 93.9%, while its specificity was 88.5% and its positive predictive value was 93.8%.

CONCLUSIONS

Our results suggest that FDG-PET is an effective tool for differentiating between benign and malignant pleural diseases.

Metabolic significance of the pattern, intensity and kinetics of 18F-FDG uptake in malignant pleural mesothelioma

BACKGROUND

Malignant pleural mesothelioma is an aggressive neoplasm with a highly variable course. This pilot study evaluated the significance of the pattern, intensity and kinetics of 18F-FDG uptake in mesothelioma in the context of histopathology and surgical staging.

METHODS

Sixteen consecutive patients with pleural disease on CT scan underwent 18F-FDG imaging. Imaging was performed with a dual detector gamma camera operating in coincidence mode. Semiquantitative image analysis was performed by obtaining lesion-to-background ratios (18F-FDG uptake index) and calculating the increment of 18F-FDG lesion uptake over time (malignant metabolic potential index (MMPi)).

RESULTS

Twelve patients had histologically proven malignant mesotheliomas (10 epithelial, two sarcomatoid). Thirty two lesions were positive for tumour. Patterns of uptake matched the extent of pleural and parenchymal involvement observed on CT scanning and surgery. Mean (SD) 18F-FDG uptake index for malignant lesions was 3.99 (1.92), range 1.5-9.46. Extrathoracic spread and metastases had higher 18F-FDG uptake indices (5.17 (2)) than primary (3.42 (1.52)) or nodal lesions (2.99 (1)). No correlation was found between histological grade and stage. The intensity of lesion uptake had poor correlation with histological grade but good correlation with surgical stage. 18F-FDG lesion uptake increased over time at a higher rate in patients with more advanced disease. The MMPi was a better predictor of disease aggressiveness than the histological grade.

CONCLUSIONS

This pilot study suggests that the pattern, intensity, and kinetics of 18F-FDG uptake in mesothelioma are good indicators of tumour aggressiveness and are superior to the histological grade in this regard.