The role of FDG PET-CT in differential diagnosis of pleural pathologies

doi:10.1016/j.remn.2011.06.002

Revista Española de Medicina Nuclear e Imagen Molecular

Volume 31, Issue 4, July–August 2012, Pages 187-191

https://doi.org/10.1016/j.remn.2011.06.002 Get rights and content

Abstract

Objective

This study has aimed to evaluate the impact of ^F18 Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (FDG PET-CT) in the differential diagnosis of malignant and benign pleural lesions in patients with suspected malignant pleural mesothelioma (MPM).

Material and methods

Fifty patients (32 females, 18 males; age range 24–79 years) with pleural thickening, fluid, plaques or calcification on previous CT scan were examined with FDG PET-CT. PET-CT imaging was obtained 1 h after FDG injection. In 12 patients, delayed imaging from the thoracic region was performed 2 h after injection. FDG uptake was evaluated visually and semiquantitively using standardized uptake value (SUV). FDG PET-CT findings were compared with histopathologic diagnosis.

Results

Thirty-nine patients had increased FDG uptake in pleural lesions but PET-CT results were negative in 11 patients. When compared with histopathological results in FDG positive group, 34 patients had MPM, 5 had benign pathology; in FDG negative group 8 patients had benign pathology, 3 had MPM. Of patients with delayed imaging, 9 showed increased SUV but 3 had a decreased SUV on delayed images. Increased SUV group had 4 MPM, 5 benign pathology (3 chronic granulomatous inflammation, 2 benign asbestotic plaque). Decreased SUV group all had benign pathology (fibrosis, chronic inflammation, myofibrosis).

Discussion

FDG PET-CT is a useful imaging modality in differential diagnosis of malignant and benign pleural lesions. Delayed imaging seems to be useful if there is a decrease in SUV suggesting a benign pathology but does not seem to contribute to the differential diagnosis if the SUV is increased.

Resumen

Introduccıón

El propósito de este estudio fue el de estudiar el impacto de F-18 Fluoro Desoxi Tomografía-Tomografía por Emisión de tomografía computerizada (FDG y PET-TAC) sobre la diagnosis diferencial de lesiones benignas y malignas en pacientes con sospecha de mesotelioma pleural maligno.

Pacientes y métodos

Cincuenta pacientes (32 mujeres, 18 hombres, rango de edad 24-79 años, edad media 57,6) con engrosamiento pleural, derrame pleural, placas o calcificaciones vistas en imágenes en estudios previos con TAC fueron sometidos a la PET-TAC con FDG. Tras la inyección intravenosa de la FDG, se realizaron imágenes PET-TAC al cabo de una hora. Se obtuvieron imágenes tardías de la región torácica a las 2 horas de la inyección. Se llevaron a cabo análisis visual y semi cuantitativos con el valor de captación estándar (SUV). Los resultados del FDG PET-TAC fueron comparados con el diagnóstico histopatológico.

Resultados

39 pacientes demostraron captación aumentada en lesiones pleurales. Los resultados en la PET-TAC fueron negativos en 11 pacientes. Al comparar los resultados histopatológicos en el grupo de FDG-positivo, 34 pacientes tenían mesotelioma pleural maligno (MPM), 5 pacientes tenían patologías benignas. En el grupo FDG-negativo, las patologías fueron benignas en 8 pacientes, 3 pacientes tuvieron MPM. En los pacientes con imágenes tardías, 9 demostraron SUV aumentado, pero 3 tuvieron SUV disminuido en las imágenes tardías. En el grupo con SUV aumentado, 4 tuvieron MPM, 5 patología benigna (3, inflamación granulomatosa, y 2 placas asbestosis benignos). En el grupo de SUV disminuido, todos tuvieron patología benigna (la fibrosis, inflamación crónica, miofibrosis).

Dıscusıón

La FDG PET-TAC es una modalidad de imágenes útil en el diagnóstico diferencial de lesiones pleurales benignas y malignas. Imágenes tardías parecen ser útiles si existe una disminución en SUV sugerente de una patología benigna. Sin embargo, no parece contribuir a un diagnóstico diferencial si el SUV se aumenta.

Introduction

FDG PET has been a well accepted functional imaging method in various malignancies in oncology in recent years. Malignant pleural mesothelioma (MPM) is a rare cancer type arising from mesothelial cells of pleura and it is the most frequent cancer type among primary malignancies of the pleura.1, 2 MPM is closely associated with asbestosis and there are settlements having asbestos containing soils in Gaziantep and in its neighbourhood.³ Computed tomography (CT) is the first line diagnostic method in pleural pathologies.4, 5 However, CT cannot distinguish benign pleural pathologies from MPM.5, 6 In literature, patient groups are generally small, and most of the studies are with FDG PET alone, and also combined studies as FDG PET-CT are limited in number. The aim of this study is to assess the role of FDG PET-CT in differential diagnosis of malignant pleural disease in patients having pleural pathologies such as pleural mass, pleural thickening and pleural effusion, in assessing invasion of the disease (staging) in malignant ones, the influence of PET-CT results on patients management, the correlation between SUV (which is a semiquantitative parameter) of the patients.

Section snippets

Patients

Fifty patients [32 female (64%) and 18 male (36%)] with pleural pathologies such as pleural mass, pleural thickening and pleural effusion referred to Gaziantep University, Nuclear Medicine Department for differentional diagnosis and staging with FDG PET-CT imaging with suspected malignancy were evaluated retrospectively. Maximum FDG uptake levels detected in pleural thickening areas, pleural fluid and mediastinal lymph nodes were recorded. Substracted materials in the consequence of processes

Results

Female/male ratio was 1.8. Age range was 24–79, and the mean age was 57.6 [the youngest 24, the oldest 79]. Mean age of females was 55.3 years (age range 24–79), and of males was 60.1 years (age range 24–76).

Discussion

FDG PET imaging, revealing metabolic activity of disease rather than its morphological structure, is considerably successful in diagnosis of malignant pleural pathologies/lesions.7, 9 MPM mostly have high level of FDG affinity due to increased glucose metabolisms increasing efficiency of FDG PET in diagnosis. As it was monitored in our study, thickened pleural surfaces involved by the disease generally show themselves in PET images with mid-high level FDG deposit. Sarcomatous type MPM generally

Conflict of interests

Authors declare that they do not have any conflict of interests.

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Cited by (16)

A PET-CT score for discriminating malignant from benign pleural effusions
2023, Medicina Clinica
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.
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.
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.
PET-CT score was shown to provide relevant information for the identification of malignant pleural effusion.
Los estudios PET-TAC previos en el análisis del derrame pleural son contradictorios. Nuestro objetivo es desarrollar una puntuación mediante PET-TAC para diferenciar entre derrames benignos y malignos.
Estudio prospectivo en pacientes con derrame pleural a los que se realizó una PET-TAC desde octubre de 2013 hasta octubre de 2019 (cohorte de referencia). Los datos analizados fueron: engrosamiento lineal; engrosamiento nodular; nódulos; masas; engrosamiento circunferencial; afectación pleural mediastínica y cisural; ganglios linfáticos torácicos; loculación pleural; consolidación; calcificación pleural; cardiomegalia; derrame pericárdico; derrame bilateral; masa pulmonar; metástasis hepáticas y otras neoplasias malignas extrapleurales. Se calculó el SUV de todos estos parámetros. Los resultados se validaron en una cohorte independiente.
Se incluyó a 199 pacientes en la cohorte de referencia (91 derrames malignos y 108 benignos). Los parámetros que mostraron más utilidad para discriminar ambos derrames y desarrollar una puntuación fueron: engrosamiento pleural nodular, nódulos pleurales con SUV > 7,5, masa pulmonar o malignidad extrapleural (10 puntos cada uno), ganglio en cadena mamaria con SUV > 4,5 (5 puntos) y cardiomegalia (–1 punto). Con un punto de corte > 9 en la cohorte de derivación, se estableció el diagnóstico de derrame pleural maligno con una sensibilidad del 87,9%, especificidad del 90,7%, valor predictivo positivo del 88,9%, valor predictivo negativo del 89,9% razón de verosimilitud positiva del 7,81 y razón de verosimilitud negativa del 0,106. Estos resultados fueron validados en una cohorte prospectiva independiente de 75 pacientes.
Una puntuación basada en PET-TAC proporciona información relevante para el diagnóstico del derrame pleural maligno.
Positron emission tomography-computed tomography (PET-CT) in suspected malignant pleural effusion. An updated systematic review and meta-analysis
2021, Lung Cancer
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.
Imaging of the Pleura: CT, MRI and PET
2021, Encyclopedia of Respiratory Medicine, Second Edition
Despite the development of thoracic ultrasound, there remains a crucial role for three-dimensional cross-sectional imaging in the investigation and management of pleura disease. Traditionally this has been in the form of computed tomography (CT) which has become established as a common imaging modality in routine standard practice, however the roles of magnetic resonance imaging (MRI) and positron emission tomography in imaging the pleura are increasing and becoming superiorly defined. The mechanisms, roles and utilities of all three modalities in common elements of pleural disease are explored in this article.
Early Contrast Enhancement: A novel magnetic resonance imaging biomarker of pleural malignancy
2018, Lung Cancer
Pleural Malignancy (PM) is often occult on subjective radiological assessment. We sought to define a novel, semi-objective Magnetic Resonance Imaging (MRI) biomarker of PM, targeted to increased tumour microvessel density (MVD) and applicable to minimal pleural thickening.
60 consecutive patients with suspected PM underwent contrast-enhanced 3-T MRI then pleural biopsy. In 58/60, parietal pleura signal intensity (SI) was measured in multiple regions of interest (ROI) at multiple time-points, generating ROI SI/time curves and Mean SI gradient (MSIG: SI increment/time). The diagnostic performance of Early Contrast Enhancement (ECE; which was defined as a SI peak in at least one ROI at or before 4.5 min) was compared with subjective MRI and Computed Tomography (CT) morphology results. MSIG was correlated against tumour MVD (based on Factor VIII immunostain) in 31 patients with Mesothelioma.
71% (41/58) patients had PM. Pleural thickening was <10 mm in 49/58 (84%). ECE sensitivity was 83% (95% CI 61–94%), specificity 83% (95% CI 68–91%), positive predictive value 68% (95% CI 47–84%), negative predictive value 92% (78–97%). ECE performance was similar or superior to subjective CT and MRI. MSIG correlated with MVD (r = 0.4258, p = .02).
ECE is a semi-objective, perfusion-based biomarker of PM, measurable in minimal pleural thickening. Further studies are warranted.
Pleural irregularities and mediastinal pleural involvement in early stages of malignant pleural mesothelioma and benign asbestos pleural effusion
2016, European Journal of Radiology
To elucidate differences in the level and localization of pleural irregularities in early malignant pleural mesothelioma (eMPM) and benign asbestos pleural effusion (BAPE) using CT.
Retrospective assessment of CT findings of consecutive patients with BAPE at a single centre and patients with eMPM reported in Japanese vital statistics.
Thirty-six patients with confirmed diagnoses of BAPE and sixty-six patients with confirmed diagnoses of eMPM (mesothelioma stages T1 or T2) were included. Informed consent, CT scans, and clinical and pathologic details were obtained for all patients and were reviewed by one radiologist, two pathologists, and two pulmonologists. Asbestosis, pleural plaque, rounded atelectasis, and diffuse pleural thickening were assessed in all patients.
Prevalence of asbestosis, pleural plaque, rounded atelectasis, and diffuse pleural thickening was significantly higher in the BAPE group. Low-level irregularity was more common in the BAPE group (p < 0.001), whereas high-level irregularity, mediastinal localization, and interlobar fissure were more prevalent in the eMPM group (p < 0.001). Interlobar pleural irregularity was not observed in any patients in the BAPE group, although 55% of patients in the eMPM group showed interlobar pleural irregularity. Mediastinal pleural involvement was observed in 74% of patients in the eMPM group and had a positive predictive value of 89%.
This study demonstrates that the level and localization of plural irregularities significantly differed between patients with BAPE and eMPM. Large-scale prospective studies are needed to fully establish the diagnostic utility of such differences.
Accuracy of fluorodeoxyglucose-PET imaging for differentiating benign from malignant pleural effusions: A meta-analysis
2015, Chest
Citation Excerpt :
The intended use of the index test was to discriminate between benign and malignant pleural effusions (or thickening) either in patients with effusions of uncertain etiology,8, 10, 11, 16, 20, 32 a previously diagnosed lung cancer,6, 15, 27, 29 or a suspected or confirmed MPM.13, 25, 30, 33 Moreover, FDG-PET imaging metabolic activity was interpreted by a qualitative method in seven studies,8, 10, 11, 13, 15, 16, 32 a semiquantitative method in three studies,20, 25, 33 and by both in four studies.6, 27, 29, 30 For semiquantitative assessments over a region of interest, SUVmax optimal cutoff discriminating values ranged from 2.2 to 3.5.
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.
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.
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.
The moderate accuracy of PET-CT imaging using semiquantitative readings precludes its routine recommendation for discriminating malignant from benign pleural effusions.

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Original articleThe role of FDG PET-CT in differential diagnosis of pleural pathologiesEl papel de FDG PET-TAC en el diagnóstico diferencial de patologías pleurales

Abstract

Objective

Material and methods

Results

Discussion

Resumen

Introduccıón

Pacientes y métodos

Resultados

Dıscusıón

Introduction

Section snippets

Patients

Results

Discussion

Conflict of interests

Respir Med

Clin Chest Med

Eur J Radiol

Eur J Radiol

Chest

J Thorac Cardiovasc Surg

Semin Roentgenol

Chest

J Thorac Cardiovasc Surg

Lung Cancer

Nonmalignant pleural lesions due to environmental exposure to asbestos: a field-based, cross-sectional study

Eur Respir J

Original article
The role of FDG PET-CT in differential diagnosis of pleural pathologiesEl papel de FDG PET-TAC en el diagnóstico diferencial de patologías pleurales