The maximum standardized uptake values on integrated FDG-PET/CT is useful in differentiating benign from malignant pulmonary nodules

Prognostic impact of venous thromboembolism on the course of sarcoidosis: A multicenter retrospective case-control study

Sarcoidosis is an independent risk factor for venous thromboembolism (VTE). However, the characteristics and clinical evolution of sarcoidosis patients presenting a VTE (sarcoidosis/VTE group) in the course of their disease are not known. Consequently, if VTE occurrence is associated with a more severe disease is still pending. We conducted a retrospective case-control study of sarcoidosis/VTE patients compared to matched sarcoidosis controls without VTE in two French tertiary centers, analysed and compared the clinical, biological, functional, imaging and evolutive profiles of the two groups. Sixty-one patients were included with at least one episode of VTE during course of sarcoidosis. At sarcoidosis onset (before/at the time of VTE occurrence) the number of affected organs, radiological stages and pulmonary functional tests were not significantly different between the two groups. In contrast, we found that sarcoidosis/VTE patients required more frequently a systemic immunosuppressive therapy (corticosteroids and/or immunosuppressors, 79% versus 58%; p = 0.008). The functional course was also poorer in sarcoidosis/VTE patients with a more frequent decrease in functional vital capacity (33% versus 18% in sarcoidosis/VTE patients and controls, respectively, p = 0.008). Finally, sarcoidosis/VTE patients presented more frequently with pulmonary hypertension (10% versus 1% in patients and controls, respectively, p = 0.006), and their survival was significantly worse (log-rank p <0.001). The occurrence of VTE during sarcoidosis is associated with a more severe disease and a poorer prognosis. The occurrence of VTE during sarcoidosis might signal a more inflammatory and/or evolutive disease in sarcoidosis/VTE patients and should be taken in consideration when designing therapeutic strategies for them.

Evaluation of hypermetabolic mediastinal-hilar lymph nodes determined by PET/CT with EBUS-TBNA and calculation of SUVmax cutoff values in differentiation of malignancy

Computed tomography (CT) and positron emission tomography (PET) are the most commonly used methods for diagnosis and staging in both malignant and benign diseases of the lung parenchyma and mediastinum. Endobronchial ultrasonography (EBUS) guided transbronchial needle aspiration biopsy (TBNA) has become widespread in recent years because it allows minimally invasive tissue sampling. PET-CT has high sensitivity in the diagnosis of malignancy but has low specificity. The false positive rate is high with the SUVmax 2.5 cutoff value, which is widely used in studies about malignancy. In our study, we evaluated lymph nodes with high F18-fluorodeoxyglucose (FDG) uptake on PET/CT and sampled by EBUS-TBNA. We aimed to calculate the new SUVmax cutoff values in the differentiation of malignancy. Our study included 103 patients who were examined for any reason and who underwent biopsy with EBUS-TBNA due to mediastinal or hilar lymph node enlargement on PET-CT. The relationship between PET-CT findings and EBUS findings, EBUS-TBNA results was evaluated. Biopsies were taken from 140 lymph nodes in 103 patients included in our study, and 39 (27.8%) were diagnosed as malignant. In our study, when the SUVmax cutoff value in PET-CT is taken as 2.54, the sensitivity is 98%, but the specificity remains at the level of 12%. When the SUVmax cutoff value in PET-CT was taken as 4.58, the sensitivity was 92% and the specificity was 49%. When this value was accepted as 5.25, and 6.09 the sensitivity was respectively 90% and 85%, the specificity was respectively 52% and 60%. In evaluations, we conducted in order to determine different SUVmax cutoff values that can be used for higher sensitivity and specificity in malignancy studies, the cutoff values were 4.58, 5.25, and 6.09. It is thought that these cutoff values will be useful both for diagnosing malignancy and for distinguishing benign pathologies.

Prognostic Significance of Volumetric Parameters Based on FDG PET/CT in Patients with Lung Adenocarcinoma Undergoing Curative Surgery

INTRODUCTION

FDG PET/CT is a robust imaging modality to diagnose and stratify prognoses for non-small cell lung carcinoma. However, the role of FDG PET/CT in operable lung adenocarcinoma patients has not been previously investigated in a large cohort with varying pathological stages. The prognostic value of volumetric parameters based on FDG PET/CT was investigated in patients with stage I-III lung adenocarcinoma receiving curative surgery.

METHODS

This retrospective study included 432 patients with lung adenocarcinoma undergoing preoperative FDG PET/CT between January 2016 and December 2017. Clinicopathologic variables, conventional image parameters, such as the maximum standardized uptake value (SUVmax) and mean SUV (SUVmean) of the primary tumor, and volumetric parameters, such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG), were included in Cox regression analysis. Subgroup analysis was conducted to compare hazard ratios (HRs) based on MTV in each pathological stage. A new staging system including volumetric parameters was suggested.

RESULTS

A total of 432 patients (median age: 62 years; interquartile range: 56-70 years; 225 males) were evaluated. Sex, age, presence of EGFR mutation, pathological stage, MTV, and TLG of the primary tumor were selected as statistically significant prognostic factors for overall survival irrespective of other variables (OS; p < 0.05 for all). Pathological stage, MTV, and TLG of the primary tumor were selected as statistically significant prognostic factors for disease-free survival irrespective of other variables (p < 0.05 for all). The suggested new staging system including MTV as an additional criterion showed better discrimination and prediction for OS than the conventional pathological staging system despite statistical insignificance (concordance index: 0.698 vs. 0.673).

CONCLUSIONS

The volumetric parameters of the primary tumor based on preoperative FDG PET/CT were independent prognostic factors in addition to pathological stage in patients with operable lung adenocarcinoma. The suggested new staging system considering MTV predicted the prognoses better than the conventional pathological staging system.

Imaging of Invasive Fungal Infections- The Role of PET/CT

Over the last decades, the population at risk for invasive fungal disease (IFD) has increased because of medical therapy advances and diseases compromising patients' immune systems. The high morbidity and mortality associated with invasive fungal disease in the immunocompromised present the challenge of early diagnosis of the IFD and the need to closely monitor the infection during treatment. The definitive diagnosis of invasive fungal disease based on culture or histopathological methods often has reduced diagnostic accuracy in the immunocompromised and may be very invasive. Less invasive and indirect evidence of the fungal infection by serology and imaging has been used for the early diagnosis of fungal infection before definitive results are available or when the definitive methods of diagnosis are suboptimal. Imaging in invasive fungal disease is a non-invasive biomarker that helps in the early diagnosis of invasive fungal disease but helps follow-up the infection during treatment. Different imaging modalities are used in the workup to evaluate fungal disease. The different imaging modalities have advantages and disadvantages at different sites in the body and may complement each other in the management of IFD. Positron emission tomography integrated with computed tomography with [18F]Fluorodeoxyglucose (FDG PET/CT) has helped manage IFD. The combined functional data from PET and anatomical data from the CT from almost the whole body allows noninvasive evaluation of IFD and provides a semiquantitative means of assessing therapy. FDG PET/CT adds value to anatomic-based only imaging modalities. The nonspecificity of FDG uptake has led to the evaluation of other tracers in the assessment of IFD. However, these are mainly still at the preclinical level and are yet to be translated to humans. FDG PET/CT remains the most widely evaluated radionuclide-based imaging modality in IFD management. The limitations of FDG PET/CT must be well understood, and more extensive prospective studies in uniform populations are needed to validate its role in the management of IFD that can be international guidelines.

A novel diagnostic model for differentiation of lung metastasis from primary lung cancer in patients with colorectal cancer

Objective

This study aimed to evaluate the ¹⁸F-FDG PET/CT in differentiating lung metastasis(LM) from primary lung cancer(LC) in patients with colorectal cancer (CRC).

Methods

A total of 120 CRC patients (80 male, 40 female) who underwent ¹⁸F-FDG PET/CT were included. The diagnosis of primary lung cancer or lung metastasis was based on histopathology The patients were divided into a training cohort and a validation cohort randomized 1:1. Independent risk factors were extracted through the clinical information and ¹⁸F-FDG PET/CT imaging characteristics of patients in the validation cohort, and then a diagnostic model was constructed and a nomograms was made. ROC curve, calibration curve, cutoff, sensitivity, specificity, and accuracy were used to evaluate the prediction performance of the diagnostic model.

Results

One hundred and twenty Indeterminate lung lesions (ILLs) (77 lung metastasis, 43 primary lung cancer) were analyzed. No significant difference in clinical characteristics and imaging features between the training and the validation cohorts (P > 0. 05). Using uni-/multivariate analysis, pleural tags and contour were identified as independent predictors. These independent predictors were used to establish a diagnostic model with areas under the receiver operating characteristic curves (AUCs) of 0.92 and 0.89 in the primary and validation cohorts, respectively. The accuracy rate of the diagnostic model for differentiating LM from LC were higher than that of subjective diagnosis (P < 0.05).

Conclusions

Pleural tags and contour were identified as independent predictors. The diagnostic model of ILLs in patients with CRC could help differentiate between LM and LC.

Prognostic Significance of Pseudotime from Texture Parameters of FDG PET/CT in Locally Advanced Non-Small-Cell Lung Cancer with Tri-Modality Therapy

Simple Summary

Although texture parameters of F-18 fluorodeoxyglucose positron emission tomography/computed tomography images were known to associate tumor biology and clinical features, the types and implications of parameters are too various and complicated. To overcome the limitation of texture parameter, we attempted to produce a new simplified parameter from texture parameters of F-18 fluorodeoxyglucose positron emission tomography/computed tomography images in lung cancer patients using pseudotime analysis. Pseudotime analysis is a recently developed method to explore changes in cell or tissue characteristics based on transcriptomic expression. It is the first study to apply pseudotime analysis into radiomics dataset other than transcriptomics data. Herein, we demonstrated that pseudotime can be successfully estimated from texture parameters. In the aspect of prognostic prediction, pseudotime was an independent prognostic factor for overall survival in contrast to conventional parameters such as metabolic tumor volume and total lesion glycolysis. This study showed possibility of integrating various texture parameters into single parameter which reflects disease progression status. Pseudotime, as a concrete value of disease progression, is expected to be used in clinical field to evaluate disease and predict prognosis.

Abstract

Texture analysis provides image parameters from F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). Although some parameters are associated with tumor biology and clinical features, the types and implications of these parameters are complicated. We applied pseudotime analysis, which has recently been used to estimate changes in individual sample characteristics, to texture parameters from FDG PET/CT images of locally advanced non-small-cell lung cancer (NSCLC) patients undergoing neoadjuvant concurrent chemoradiation therapy (CCRT) followed by surgery. Our subjects were 303 NSCLC patients who underwent pretherapeutic FDG PET/CT and tri-modality therapy. Texture parameters of the primary tumor were calculated from FDG PET/CT images acquired before neoadjuvant CCRT. Pseudotime analysis was performed using the PhenoPath tool. Clinicopathologic features including survival data were collected and survival analysis was performed to compare the prognostic significances of pseudotime parameters with those of conventional PET parameters. Pseudotime was successfully estimated from texture parameters. Normalized co-occurrence homogeneity, normalized co-occurrence inverse difference moment, and black–white symmetry showed positive correlations with pseudotime, short run emphasis, normalized co-occurrence dissimilarity, and short zone emphasis negative correlation. The maximum standardized uptake value (SUV) and mean SUV were not associated with overall survival. Pseudotime, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) showed significant associations with overall survival. In contrast to MTV and TLG, pseudotime was an independent prognostic factor for overall survival. Various metabolic texture parameters can be integrated into a single parameter using pseudotime analysis. Pseudotime of the primary tumor, estimated from FDG PET/CT images, better predicts overall survival in locally advanced NSCLC patients treated with tri-modality therapy than conventional PET parameters.

Prognostic impact of the tumor volume doubling time in clinical T1 non-small cell lung cancer with solid radiological findings

BACKGROUND

The purpose of this study was to investigate better radiological prognostic factors in clinical T1 pure-solid non-small cell lung cancer (NSCLC).

METHODS

This study enrolled 284 patients with clinical T1 solid NSCLC who underwent anatomical lung resection. The Cox proportional hazard model was used to evaluate the prognostic impact of tumor volume doubling time (VDT) at disease-free survival (DFS) and cancer-specific survival (CSS).

RESULTS

The median VDT was 347 days. Age (hazard ratio (HR) = 1.04; 95% confidence interval (CI), 1.01-1.07) and standardized uptake value max (SUVmax) (>6.0) (HR = 2.61; 95% CI, 1.52-4.66) were identified as significantly independent worse prognostic factors for DFS in a multivariable analysis without VDT. Furthermore, a multivariable analysis without SUVmax identified age (HR = 1.06; 95% CI, 1.03-1.09), CEA (>5.0 ng/ml) (HR = 2.34; 95% CI, 1.30-4.02), tumor diameter on CT (>2.0 cm) (HR = 1.91; 95% CI, 1.18-3.13), and VDT (HR = 4.03; 95% CI, 2.41-6.93) as significantly independent worse prognostic factors for DFS.

CONCLUSIONS

The VDT value could be a useful prognostic factor in clinical T1 solid NSCLC.

Nonmalignant Thoracic Disorders: An Appraisal of Fluorodeoxyglucose and Non-fluorodeoxyglucose PET/Computed Tomography Applications

PET/computed tomography (CT) with fluorodeoxyglucose and nonfluorodeoxyglucose PET tracers has established itself in the management of malignant disorders. Its role in the assessment of nonmalignant conditions, such as infectious and noninfectious inflammatory diseases and other benign conditions, has emerged independently and alongside its role being evaluated in malignancy and continues to evolve. It is evident that PET/CT has the potential to play a significant role in various nonmalignant disorders of the thorax. This review highlights current developments and areas where PET/CT has a potential to impact the clinical management of nonmalignant thoracic conditions with special focus on nonfluorodeoxyglucose tracers.

Heterogeneous imaging features of Aspergillosis at 18F-FDG PET/CT

Aspergillosis is one of the most frequent fungal infections, whose morbidity can be life-threatening, especially in some categories of patients such as immunocompromised ones. It can have various clinical presentation scenarios and should be considered when making differential diagnosis in patients with pulmonary and extrapulmonary involvement. 18F-FDG PET/CT is a whole-body diagnostic technique that can help in the study of the disease, guiding the patient management thanks to the possibility to recognize infection sites and extension. The aim of this manuscript is to provide an overview of the wide spectrum of disease presentation. Literature regarding 18F-FDG PET/CT in histologically confirmed aspergillosis cases has been revised to describe all its possible features, both usual and unusual to guide imaging interpretation. 18F-FDG PET/CT is a diagnostic tool that can help in the recognition of the heterogenous infection’s presentation, allowing the clinicians to make a prompt diagnosis and to have the most accurate management of the disease. Furthermore, other PET/CT radiopharmaceutical role in Aspergillosis imaging study have been presented.

Residual meta-iodobenzyl guanidine (MIBG) positivity following therapy for metastatic neuroblastoma: Patient characteristics, imaging, and outcome

BACKGROUND

Meta-iodobenzylguanidine(MIBG) scans are used to detect neuroblastoma metastatic lesions at diagnosis and during posttreatment surveillance. MIBG positivity following induction chemotherapy correlates with poor outcome; however, there are reports of patients with progression-free survival despite MIBG positivity at the end of therapy. The factors distinguishing these survivors from patients who progress or relapse are unclear. FDG-positron-emission tomography (PET) scans can also detect metastatic lesions at diagnosis; however, their role in posttherapy surveillance is less well studied.

METHODS

We performed a retrospective analysis of International Neuroblastoma Staging System (INSS) stage 4 patients to identify those with residual MIBG-avid metastatic lesions on end-of-therapy scans without prior progression. Data collected included age, disease sites, histopathology, biomarkers, treatment, imaging studies, and response.

RESULTS

Eleven of 265 patients met inclusion criteria. At diagnosis three of 11 patients were classified as intermediate and eight of 11 high risk; nine of 11 had documented marrow involvement. Histologic classification was favorable for four of 10 and MYCN amplification was detected in zero of 11 cases. The median time with persistent MIBG positivity following treatment was 1.5 years. Seven patients had at least one PET scan with low or background activity. Biopsies of three of three MIBG-avid residual lesions showed differentiation. All patients remain alive with no disease progression at a median of 4.0 years since end of therapy.

CONCLUSION

Persistently MIBG-avid metastatic lesions in subsets of patients following completion of therapy may not represent active disease that will progress. Further studies are needed to determine whether MYCN status or other biomarkers, and/or PET scans, may help identify patients with residual inactive MIBG lesions who require no further therapy.

Computational approaches to detect small lesions in 18 F-FDG PET/CT scans

Purpose

When physicians interpret ¹⁸F‐FDG PET/CT scans, they rely on their subjective visual impression of the presence of small lesions, the criteria for which may vary among readers. Our investigation used physical phantom scans to evaluate whether image texture analysis metrics reliably correspond to visual criteria used to identify lesions and accurately differentiate background regions from sub‐centimeter simulated lesions.

Methods

Routinely collected quality assurance test data were processed retrospectively for 65 different ¹⁸F‐FDG PET scans performed of standardized phantoms on eight different PET/CT systems. Phantoms included 8‐, 12‐, 16‐, and 25‐mm diameter cylinders embedded in a cylindrical water bath, prepared with 2.5:1 activity‐to‐background ratio emulating typical whole‐body PET protocols. Voxel values in cylinder regions and background regions were sampled to compute several classes of image metrics. Two experienced physicists, blinded to quantified image metrics and to each other's readings, independently graded cylinder visibility on a 5‐level scale (0 = definitely not visible to 4 = definitely visible).

Results

The three largest cylinders were visible in 100% of cases with a mean visibility score of 3.3 ± 1.2, while the smallest 8‐mm cylinder was visible in 58% of cases with a significantly lower mean visibility score of 1.5±1.1 (P < 0.0001). By ROC analysis, the polynomial‐fit signal‐to‐noise ratio was the most accurate at discriminating 8‐mm cylinders from the background, with accuracy greater than visual detection (93% ± 2% versus 76% ± 4%, P = 0.0001), and better sensitivity (94% versus 58%, P < 0.0001).

Conclusion

Image texture analysis metrics are more sensitive than visual impressions for detecting sub‐centimeter simulated lesions. Therefore, image texture analysis metrics are potentially clinically useful for ¹⁸F‐FDG PET/CT studies.

Frequent EGFR Mutations and Better Prognosis in Positron Emission Tomography-Negative, Solid-Type Lung Cancer

BACKGROUND

The differential diagnosis of a solitary solid-type lung nodule is diverse. 18F-fluorodeoxyglucose positron emission tomography (PET) has a high sensitivity in the diagnosis of solid-type lung cancers; however, PET-negative, solid-type lung cancers are rarely observed. In this study, we analyzed the clinical/genetic features and prognosis of PET-negative, solid-type lung cancers.

PATIENTS AND METHODS

Between January 2007 and February 2020, 709 patients with solid-type lung cancers (tumor size ≥2.0 cm) underwent pulmonary resection. Clinical, genetic, and prognostic features were evaluated in 27 patients (3.8%) with tumors showing negative PET results defined as SUVmax <2.0.

RESULTS

All 27 patients had lung adenocarcinoma; 23 had invasive adenocarcinomas and 4 had invasive mucinous adenocarcinomas. The PET-negative group showed high frequencies of females and never-smokers. Recurrence-free survival was significantly better in the PET-negative group compared with PET-positive counterparts extracted using propensity score matching from patients who underwent pulmonary resection during the same period (P = .0052). Furthermore, 83% of PET-negative, solid-type invasive lung adenocarcinoma patients harbored EGFR mutation, which was significantly higher than that of PET-positive, solid-type invasive lung adenocarcinoma patients (38%, n = 225) who received EGFR mutation testing in our cohort (P < .0001). PET-negative, solid-type lung adenocarcinoma patients with EGFR mutations had significantly better recurrence-free survival compared with PET-positive, solid-type lung adenocarcinoma patients with EGFR mutations extracted using propensity score matching (P = .0030).

CONCLUSION

PET-negative, solid-type lung cancers are characterized with a high incidence of EGFR mutation and a better prognosis compared with PET-positive, solid-type lung cancer.

Diagnostic and Management Considerations in a Patient With Primary Pulmonary Meningioma With Associated Micro-Solid Nodules

Primary pulmonary meningiomas (PPMs) are rare mesodermal tumors that arise in the lung and are most often incidentally identified as single pulmonary nodules. Most cases of PPM are benign, and surgical resection remains the primary curative treatment. We describe the case of a 65-year-old asymptomatic female who presented with an incidentally identified 2.5 x 1.7-cm lobulated, non-calcified mass in the right lower lobe of the lung, which was diagnosed as PPM that had low fluorodeoxyglucose (FDG)-avidity and associated sub-centimeter nodules present in the same lobe. The patient was closely monitored and the nodules showed essentially no interval enlargement over several months. Given the disparate locations and small sizes of the nodules, no surgical resection was planned. The patient remained clinically stable, and close medical monitoring was determined to be the best course of action. Our case highlights the viability of medical monitoring as an alternative to surgery in asymptomatic patients with benign PPMs that have associated micronodules.

Flip flop fungus sign: an FDG PET sign of benign pulmonary nodules

A 71-year-old man was referred to pulmonary clinic for incidental findings of hypermetabolic lung nodule and mediastinal adenopathy on CT FDG PET performed for evaluation of cough. The patient underwent bronchoscopy with endobronchial ultrasound that was non-diagnostic. The patient was subsequently sent for video-assisted thoracoscopic lymph node biopsy notable for confluent caseating granulomas due to chronic infection by Histoplasma capsulatum Review of previous PDG PET was notable for the flip flop fungus sign-a PDG PET finding that could have altered the patients' clinical course by potentially avoiding the need for invasive surgical tissue diagnosis.

Pattern of FDG-PET uptake in lipoid pneumonia simulating lung cancer

Lipoid pneumonia presents with a variety of lung abnormalities, particularly mass forming lesions that mimic lung cancers. While ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) is expected to discriminate both diseases, some previous reports showed pseudo-positive FDG uptake in lipoid pneumonia. Here, we report a case of pathologically proven chronic lipoid pneumonia in a 78-year-old Japanese man. Computed tomography (CT) showed multi-lobar mass-forming lesions with a fat-density. PET confirmed the spotty accumulation of FDG in the corresponding fat-density area on CT, suggesting lipoid pneumonia. We reviewed the literature and discussed the FDG uptake patterns in lipoid pneumonia.

To Biopsy or Not to Biopsy?: A Matched Cohort Analysis of Early-Stage Lung Cancer Treated with Stereotactic Radiation with or Without Histologic Confirmation

PURPOSE

For nonoperable stage I non-small cell lung cancer, stereotactic body radiation therapy (SBRT) has emerged as a standard treatment option. We aimed to compare the clinical outcomes of lung SBRT between patients with versus without pathologic cancer diagnosis.

METHODS AND MATERIALS

We included patients treated by SBRT for a single pulmonary lesion between July 2009 and July 2017. Patients in the clinical diagnosis group had a positron emission tomography/computed tomography scan showing hypermetabolism, growth of the mass on sequential computed tomography, and were not eligible for biopsy, refused biopsy, or had an inconclusive biopsy. For each of those patients, a matched pair in the pathologic diagnosis group was identified by matching for patient, treatment, and tumoral characteristics. We performed a power calculation to estimate the sample size required to detect a difference arising from a 5% or 15% rate of benign processes in the group without pathology.

RESULTS

A total of 924 lung SBRT treatments were performed among 878 patients from 2009 to 2017. Within this population, 131 patients were treated based on clinical findings. They were matched with 131 patients with a pathologic diagnosis who received treatment. At 3 years, no significant differences were observed in overall survival (hazard ratio [HR], 1.2; 95% confidence interval [CI], 0.7-2.1), local control (HR, 0.9; 95% CI, 0.4-2), or regional (HR, 0.5; 95% CI, 0.2-1.4) or distant recurrence (HR, 0.6; 95% CI, 0.3-1.1).

CONCLUSIONS

In our population, we found no clinically significant difference in patterns of recurrence or survival after lung SBRT for patients who had received clinical versus pathological diagnoses. There was, however, a trend toward more distant recurrences in the pathologic diagnosis group. Our power calculation suggests that data from multiple institutions would be required to rule out a difference in outcomes due to 5% to 15% of clinically diagnosed cases being treated for benign processes.

Evaluation of the diagnostic efficacy of 18 F-Fluorine-2-Deoxy-D-Glucose PET/CT for lung cancer and pulmonary tuberculosis in a Tuberculosis-endemic Country

OBJECTIVE

To determine the diagnostic efficacy of ¹⁸ F-FDG PET/CT in distinguishing between pulmonary tuberculosis (PTB) and lung cancer in solitary pulmonary nodule (SPN) in a country with a high prevalence of PTB.

METHODS

Patients with SPN who underwent ¹⁸ F-FDG PET/CT imaging were retrospectively included in the study. The final diagnosis was established by histopathology. A linear regression equation was fitted to a scatter plot of size and SUVmax of lung cancer and PTB. ROC was used to determine the optimal cutoff values and diagnostic accuracy of ¹⁸ F-FDG PET/CT in PTB and lung cancer.

RESULTS

About 514 patients were included with the mean age of 57.5 ± 10.6 years. Four hundred and seventy-five cases were diagnosed as lung cancer, and 39 cases were PTB by histopathology. ¹⁸ F-FDG PET/CT had sensitivity, specificity, and diagnostic accuracy of 96.0%, 48.7%, and 92.0%, respectively. Utilization of SUVmax ≥2.5 in SPN resulted in 2 and 11 false positives cases of lung cancer and PTB, respectively, whereas SUVmax <2.5 resulted in 18 and 10 false-positive cases of lung cancer and PTB, respectively. The SUVmax and the size of short-axis in the lung cancer group were statistically higher than those in the PTB group. The linear regression equation parameters indicated the slope of the regression line of lung cancer was greater than that of PTB. The ROC curve demonstrated the SUVmax cutoff values of 4.85 and 2.25 for lung cancer and PTB, respectively for predicting the diagnostic accuracy of ¹⁸ F-FDG PET/CT.

CONCLUSION

¹⁸ F-FDG PET/CT has a higher sensitivity and diagnostic accuracy for malignant SPN. However, it has high false-positive rate and low specificity in tuberculosis endemic areas. Neither SUVmax nor the sizes of the nodules are valuable parameters for distinguishing between lung cancer and PTB. However, the SPN with larger short-axis and higher SUVmax would be inclined to malignant tumor.

Lung Cancer Recurrence: 18F-FDG PET/CT in Clinical Practice

OBJECTIVE

The purpose of this article is to summarize the clinical utility of ¹⁸F-FDG PET/CT in the evaluation of lung cancer recurrence with an emphasis on typical anatomic and metabolic patterns of recurrence, expected posttherapeutic changes, and common pitfalls of FDG PET/CT. FDG PET/CT is useful in assessing therapeutic response and in determining the extent of recurrent disease and provides a guide for targeted biopsy.

CONCLUSION

FDG PET/CT plays a crucial role in the evaluation of therapeutic response in lung cancer and guides management.

Spectral CT and its specific values in the staging of patients with non-small cell lung cancer: technical possibilities and clinical impact

AIM

To investigate how spectral computed tomography (SCT) values impact the staging of non-small cell lung cancer (NSCLC) patients.

MATERIALS AND METHODS

One hundred and thirteen patients with confirmed NSCLC were included in a prospective cohort study. All patients underwent single-phase contrast-enhanced SCT (using the fast tube voltage switching technique, 80-140 kV). SCT values (iodine content [IC], spectral slope pitch, and radiodensity increase) of malignant tissue (primary and metastases) and lymph nodes (LNs) were measured. Adrenal masses were evaluated in a virtual non-contrast series (VNS). If pulmonary embolism was present, pulmonary perfusion was analysed as an additional finding.

RESULTS

Fifty-two untreated primary NSCLC lesions were evaluable. Lung adenocarcinoma had significantly higher normalised IC (NIC: 19.37) than squamous cell carcinoma (NIC: 12.03; p=0.035). Pulmonary metastases were not significantly different from benign lung nodules. A total of 126 LNs were analysed and histologically proven metastatic LNs (2.08 mg/ml) had significantly lower IC than benign LNs (2.58 mg/ml; p=0.023). Among 34 adrenal masses, VNS identified adenomas with high sensitivity (91%) and specificity (100%). In two patients, a perfusion defect due to pulmonary embolism was detected in the iodine images.

CONCLUSION

SCT may contribute to the differentiation of histological NSCLC subtypes and improve the identification of LN metastases. VNS differentiates adrenal adenoma from metastasis. In case of pulmonary embolism, iodine imaging can visualise associated pulmonary perfusion defects.

Fluorine 18-FDG PET/CT and Diffusion-weighted MRI for Malignant versus Benign Pulmonary Lesions: A Meta-Analysis

Purpose To perform a meta-analysis of the literature to compare the diagnostic performance of fluorine 18 fluorodeoxyglucose PET/CT and diffusion-weighted (DW) MRI in the differentiation of malignant and benign pulmonary nodules and masses. Materials and Methods Published English-language studies on the diagnostic accuracy of PET/CT and/or DW MRI in the characterization of pulmonary lesions were searched in relevant databases through December 2017. The primary focus was on studies in which joint DW MRI and PET/CT were performed in the entire study population, to reduce interstudy heterogeneity. For DW MRI, lesion-to-spinal cord signal intensity ratio and apparent diffusion coefficient were evaluated; for PET/CT, maximum standard uptake value was evaluated. The pooled sensitivities, specificities, diagnostic odds ratios, and areas under the receiver operating characteristic curve (AUCs) for PET/CT and DW MRI were determined along with 95% confidence intervals (CIs). Results Thirty-seven studies met the inclusion criteria, with a total of 4224 participants and 4463 lesions (3090 malignant lesions [69.2%]). In the primary analysis of joint DW MRI and PET/CT studies (n = 6), DW MRI had a pooled sensitivity and specificity of 83% (95% CI: 75%, 89%) and 91% (95% CI: 80%, 96%), respectively, compared with 78% (95% CI: 70%, 84%) (P = .01 vs DW MRI) and 81% (95% CI: 72%, 88%) (P = .056 vs DW MRI) for PET/CT. DW MRI yielded an AUC of 0.93 (95% CI: 0.90, 0.95), versus 0.86 (95% CI: 0.83, 0.89) for PET/CT (P = .001). The diagnostic odds ratio of DW MRI (50 [95% CI: 19, 132]) was superior to that of PET/CT (15 [95% CI: 7, 32]) (P = .006). Conclusion The diagnostic performance of diffusion-weighted MRI is comparable or superior to that of fluorine 18 fluorodeoxyglucose PET/CT in the differentiation of malignant and benign pulmonary lesions. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Schiebler in this issue.

Solitary pulmonary nodule evaluation in regions endemic for infectious diseases: Do regional variations impact the effectiveness of fluorodeoxyglucose positron emission tomography/computed tomography

BACKGROUND

Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has become a preferred imaging modality for the evaluation of solitary pulmonary nodule (SPN), particularly in the developed world. Since FDG can concentrate in infective/inflammatory lesions, the diagnostic utility of FDG-PET can be questioned, particularly in regions endemic for infectious decisions.

AIM

To evaluate the accuracy of FDG-PET/CT in evaluation of SPNs in a population endemic for infectious disease and to assess if regional variations have an impact on its effectiveness.

MATERIALS AND METHODS

All patients who underwent an FDG/PET-CT with a clinico-radiological diagnosis of SPN categorized as indeterminate were included. Based on a maximum standardized uptake values (SUVmax) cut-off of 2.5, lesions were classified as benign (<2.5) or malignant (>2.5) and compared with gold standard histopathology. The diagnostic accuracy of PET-CT to detect malignancy was calculated. On the basis of final histopathology, lesions were grouped as (a) malignant nodules (b) infective/granulomatous nodules with a specific diagnosis and (c) nonspecific inflammatory nodules. The SUVmaxbetween these groups was compared using nonparametric statistical tests.

RESULTS

A total of 191 patients (129 males, 62 females) with a median age of 64 years (range: 36-83) were included. Totally, 144 nodules (75.3%) were malignant and 47 were benign (24.7%). Adenocarcinoma (n = 84) was the most common malignancy. Tuberculosis (n = 16) and nonspecific infections (n = 24) were the two most common benign pathologies. There was a significant overlap in the metabolic uptake of malignant (median SUVmax-11.2, range: 3.3-34.6) and tuberculous nodules (median SUVmax-10.3, range: 2.7-22.5) with no statistically difference between their SUVmaxvalues (P = 0.43). The false-positive rate was 65.2% and the false-negative rate was 5.5%. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG-PET/CT for detecting malignancy were 94.4%, 34.7%, 81.9%, 66.6%, and 79.5%, respectively.

CONCLUSIONS

Though FDG-PET scans show a very high sensitivity for malignant nodules, it has a high false-positive rate and reduced specificity when characterizing SPNs in an infectious endemic region. Physicians must be aware of this limitation in the workup of lung nodules, and regional variations must be considered before further management decisions are taken.

FDG PET/CT imaging in detecting and guiding management of invasive fungal infections: a retrospective comparison to conventional CT imaging

PURPOSE

Invasive fungal infections (IFIs) are common in immunocompromised patients. While early diagnosis can reduce otherwise high morbidity and mortality, conventional CT has suboptimal sensitivity and specificity. Small studies have suggested that the use of FDG PET/CT may improve the ability to detect IFI. The objective of this study was to describe the proven and probable IFIs detected on FDG PET/CT at our centre and compare the performance with that of CT for localization of infection, dissemination and response to therapy.

METHODS

FDG PET/CT reports for adults investigated at Peter MacCallum Cancer Centre were searched using keywords suggestive of fungal infection. Chart review was performed to describe the risk factors, type and location of IFIs, indication for FDG PET/CT, and comparison with CT for the detection of infection, and its dissemination and response to treatment.

RESULTS

Between 2007 and 2017, 45 patients had 48 proven/probable IFIs diagnosed prior to or following FDG PET/CT. Overall 96% had a known malignancy with 78% being haematological. FDG PET/CT located clinically occult infection or dissemination to another organ in 40% and 38% of IFI patients, respectively. Of 40 patients who had both FDG PET/CT and CT, sites of IFI dissemination were detected in 35% and 5%, respectively (p < 0.001). Of 18 patents who had both FDG PET/CT and CT follow-up imaging, there were discordant findings between the two imaging modalities in 11 (61%), in whom normalization of FDG avidity of a lesion suggested resolution of active infection despite a residual lesion on CT.

CONCLUSION

FDG PET/CT was able to localize clinically occult infection and dissemination and was particularly helpful in demonstrating response to antifungal therapy.

Diagnostic Accuracy of 18F-FDG PET/CT in the Staging and Assessment of Response to Chemotherapy in Children With Ewing Sarcoma

INTRODUCTION

The purpose of this study was to evaluate the potential role of fluorine-18 fluorodeoxyglucose (18F-FDG) positron-emission tomography/computed tomography (PET-CT) in the staging and assessment of chemotherapy response in Ewing sarcoma.

MATERIALS AND METHODS

For 13 patients with Ewing sarcoma, whole-body FDG PET-CT was assessed for site of primary disease, disease extent, and response to therapy. Chest CT, localized magnetic resonance imaging or CT of primary site, and bone scintigrams were evaluated for imaging features of the primary lesion and presence or absence of metastatic disease. Response to therapy was also assessed. Descriptive statistics are reported.

RESULTS

Nine patients (69%) presented metastatic disease. All metastatic lung lesions were detected by spiral CT, but some failed to be detected using FDG PET-CT. As regards bone lesions, both FDG PET-CT and bone scans were able to identify bone metastasis, but FDG PET-CT identified more lesions than bone scans. All PET-CT scans at the end of the neoadjuvant chemotherapy showed a decreased FDG uptake.

CONCLUSIONS

FDG PET-CT seems to be superior to bone scan in the detection of bone metastasis in all districts except skull bones. For pulmonary metastasis smaller than 7 mm, FDG PET-CT is less sensitive than CT. FDG PET-CT may have an important role in initial staging of Ewing sarcoma and subsequent evaluation of response to therapy.

Role of CT Density in PET/CT-Based Assessment of Lymphoma

PURPOSE

In patients with Hodgkin (HL) and non-Hodgkin lymphoma (NHL), primary staging, as well as intermediate and late response assessment, is often performed by integrated 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) positron emission tomography/X-ray computed tomography (PET/CT). The purpose of this analysis was to evaluate if findings in patients with histopathologically proven HL or NHL might correlate with semi-automated density measurements of target lesions (TLs) in the CT component of the integrated PET/CT examination.

PROCEDURES

After approval by the institutional review board, 176 lymph nodes (LN) in 90 PET/CT examinations of 90 patients were retrospectively analyzed (HL, 108 TLs out of 55 patients; NHL, 68 TLs out of 35 patients). PET/CT was performed for reasons of primary staging, response evaluation as interim PET, or as final examination after therapy, according to the clinical schedule. Analyses of TLs were performed on the basis of tracer uptake (SUV) 60 min after tracer injection and volumetric CT histogram analysis in non-contrast-enhanced CT.

RESULTS

All patients were diagnosed with HL or NHL in a pretreatment biopsy. Prior to therapy induction, staging of all patients was performed using contrast-enhanced CT of the neck to the pelvis, or by [¹⁸F]FDG PET/CT. Of the 176 TLs, 119 were classified as malignant, and 57 were benign. Malignant TLs had significantly higher CT density values compared to benign (p < 0.01).

CONCLUSION

Density measurements of TLs in patients with HL and NHL correlate with the dignity of TLs and might therefore serve as a complementary surrogate parameter for the differentiation between malignant and benign TLs. A possible density threshold in clinical routine might be a 20-Hounsfield units (HU) cutoff value to rule out benignancy in TLs that are above the 20-HU threshold.

18F-Fluoro-2-Deoxy-d-Glucose PET/Computed Tomography Evaluation of Lung Cancer in Populations with High Prevalence of Tuberculosis and Other Granulomatous Disease

Pulmonary tuberculosis infects one-third of world's population and is responsible for the high mortality and morbidity in developing countries. The presence of a high number of macrophages and lymphocytes in active tuberculosis granulomas is associated with high uptake of ¹⁸F-fluoro-2-deoxy-d-glucose on PET imaging mimicking lung cancer. In many cases, radiological features of pulmonary tuberculosis are undistinguishable from lung cancer, which makes the diagnosis difficult. Clinical history and computed tomographic (CT) findings on a hybrid PET/CT are as important as findings on a PET in the diagnosis of lung cancer.

Initial FDG-PET/CT predicts survival in adults Ewing sarcoma family of tumors

Purpose

The aim of this retrospective study was to determine, at baseline, the prognostic value of different FDG-PET/CT quantitative parameters in a homogenous Ewing Sarcoma Family of Tumors (ESFT) adult population, compared with clinically relevant prognostic factors.

Methods

Adult patients from 3 oncological centers, all with proved ESFT, were retrospectively included. Quantitative FDG-PET/CT parameters (SUV (maximum, peak and mean), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of the primary lesion of each patient were recorded before treatment, as well as usual clinical prognostic factors (stage of disease, location, tumor size, gender and age). Then, their relation with progression free survival (PFS) and overall survival (OS) was evaluated.

Results

32 patients were included. Median age was 21 years (range, 15 to 61). Nineteen patients (59%) were initially metastatic. On multivariate analysis, high SUV_max remained independent predictor of worst OS (p=0.02) and PFS (p=0.019), metastatic disease of worst PFS (p=0.01) and high SUVpeak of worst OS (p=0.01). Optimal prognostic cut-off of SUV_peak was found at 12.5 in multivariate analyses for PFS and OS (p=0.0001).

Conclusions

FDG-PET/CT, recommended at ESFT diagnosis for initial staging, can be a useful tool for predicting long-term adult patients outcome through semi-quantitative parameters.

Intraoperative Molecular Imaging Combined With Positron Emission Tomography Improves Surgical Management of Peripheral Malignant Pulmonary Nodules

OBJECTIVE

To determine if intraoperative molecular imaging (IMI) can improve detection of malignant pulmonary nodules.

BACKGROUND

18-Fluorodeoxyglucose positron emission tomography (PET) is commonly utilized in preoperative assessment of patients with solid malignancies; however, false negatives and false positives remain major limitations. Using patients with pulmonary nodules as a study model, we hypothesized that IMI with a folate receptor targeted near-infrared contrast agent (OTL38) can improve malignant pulmonary nodule identification when combined with PET.

METHODS

Fifty patients with pulmonary nodules with imaging features suspicious for malignancy underwent preoperative PET. Patients then received OTL38 before pulmonary resection. During resection, IMI was utilized to evaluate known pulmonary nodules and identify synchronous lesions. Tumor size, PET standardized uptake value, and IMI tumor-to-background ratios were compared for known and synchronous nodules via paired and unpaired t tests, when appropriate. Test characteristics of PET and IMI with OTL38 were compared.

RESULTS

IMI identified 56 of 59 (94.9%) malignant pulmonary nodules identified by preoperative imaging. IMI located an additional 9 malignant lesions not identified preoperatively. Nodules only detected by IMI were smaller than nodules detected preoperatively (0.5 vs 2.4 cm; P < 0.01), but displayed similar fluorescence (tumor-to-background ratio 3.3 and 3.1; P = 0.50). Sensitivity of IMI and PET were 95.6% and 73.5% (P = 0.001), respectively; and positive predictive values were 94.2% and 89.3%, respectively (P > 0.05). Additionally, utilization of IMI clinically upstaged 6 (12%) subjects and improved management of 15 (30%) subjects.

CONCLUSIONS

These data suggest that combining IMI with PET may provide superior oncologic outcomes for patients with resectable lung cancer.

Management of the Solitary Pulmonary Nodule

Context.—

Optimal management of the patient with a solitary pulmonary nodule entails early diagnosis and appropriate treatment for patients with malignant tumors, and minimization of unnecessary interventions and procedures for those with ultimately benign nodules. With the growing number of high-resolution imaging modalities and studies available, incidentally found solitary pulmonary nodules are an increasingly common occurrence.

Objective.—

To provide guidance to clinicians involved in the management of patients with a solitary pulmonary nodule, including aspects of risk stratification, workup, diagnosis, and management.

Data Sources.—

Data for this review were gathered from an extensive literature review on the topic.

Conclusions.—

Logical evaluation and management pathways for a patient with a solitary pulmonary nodule will allow providers to diagnose and treat individuals with early stage lung cancer and minimize morbidity from invasive procedures for patients with benign lesions.

Screening for distant metastases in head and neck cancer patients using FDG-PET and chest CT: validation of an algorithm

In patients with head and neck squamous cell carcinoma and high-risk factors, the combination of whole body FDG-PET and contrast-enhanced chest CT has the highest sensitivity and accuracy when screening for distant metastases. The aim of the present study was to retrospectively validate an earlier developed algorithm for interpreting the combination of screening PET and CT. The test cohort consisted of 47 consecutive HNSCC patients with high-risk factors for distant metastases, who had previously undergone FDG-PET and CT and had a minimum 12 months of follow-up. In 12 (26 %) patients, distant metastases were detected during screening or within 12-month follow-up. In patients with locoregional control during follow-up, the sensitivity and specificity were 55 % (95 % CI 23-83 %) and 97 % (95 % CI 82-99 %), respectively, for chest CT, 55 % (95 % CI 23-83 %) and 100 % (95 % CI 88-100 %), respectively, for PET and 73 % (95 % CI 39-94 %) and 100 % (95 % CI 88-100 %), respectively, for the combination of PET and CT. The proposed algorithm was considered to have been validated. In this algorithm, all FDG-PET positive scans for distant metastases (regardless of interpretation of a solid lung lesion on CT) and CT scans with suspicious pulmonary lesions of less than 5-mm diameter (regardless of FDG-PET findings) are considered positive for distant metastases.

Monitoring and management of lung cancer patients following curative-intent treatment: clinical utility of 2-deoxy-2-[fluorine-18]fluoro-d-glucose positron emission tomography/computed tomography

A large number of studies have demonstrated that 2-deoxy-2-[fluorine-18]fluoro-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) is superior to conventional modalities for the diagnosis of lung cancer and the evaluation of the extent of the disease. However, the efficacy of PET/CT in a follow-up surveillance setting following curative-intent treatments for lung cancer has not yet been established. We reviewed previous papers and evaluated the potential efficacy of PET-CT in the setting of follow-up surveillance. The following are our findings: 1) PET/CT is considered to be superior or equivalent to conventional modalities for the detection of local recurrence. However, inflammatory changes and fibrosis after treatments in local areas often result in false-positive findings; 2) the detection of asymptomatic distant metastasis is considered to be an advantage of PET/CT in a follow-up setting. However, it should be noted that detection of brain metastasis with PET/CT has some limitation, similar to its use in pretreatment staging; 3) additional radiation exposure and higher medical cost arising from the use of PET/CT should be taken into consideration, particularly in patients who might not have cancer after curative-intent treatment and are expected to have a long lifespan. The absence of any data regarding survival benefits and/or improvements in quality of life is another critical issue. In summary, PET/CT is considered to be more accurate and sensitive than conventional modalities for the detection of asymptomatic recurrence after curative-intent treatments. These advantages could modify subsequent management in patients with suspected recurrence and might contribute to the selection of appropriate treatments for recurrence. Therefore, PET/CT may be an alternative to conventional follow-up modalities. However, several important issues remain to be solved. PET/CT in a follow-up surveillance setting is generally not recommended in clinical practice at the moment.

Comparison of outcomes for patients with lepidic pulmonary adenocarcinoma defined by 2 staging systems: A North American experience

OBJECTIVE

Application of the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) classification of lepidic adenocarcinomas in conjunction with American Joint Committee on Cancer (AJCC) staging has been challenging. We aimed to compare IASLC/ATS/ERS and AJCC classifications, to determine if they could be integrated as a single staging system.

METHODS

We reviewed patients from 2001-2013 who had AJCC stage I lepidic adenocarcinomas, and categorized them according to IASLC/ATS/ERS guidelines: adenocarcinoma in situ (AIS); minimally invasive adenocarcinoma (MIA); or invasive adenocarcinoma (IA). We integrated the 2 classification systems by separating AIS and MIA as being stage 0, and routinely classifying IA as stage I.

RESULTS

Median follow-up was 52 months in 138 patients. The IASLC/ATS/ERS classification demonstrated a higher disease-free survival (DFS) in AIS (100%) and MIA (96%) versus IA (80%) (P = .022), and higher overall survival (OS): 100% for AIS and MIA, versus 90% for IA (P = .049). The AJCC classification identified a DFS of 87% and an OS of 94% for stage I patients. Integration of the 2 systems demonstrated higher DFS in stage 0 (98%) versus I (80%) (P = .006), and higher OS: 100% for stage 0 versus 90% for stage I (P = .014).

CONCLUSIONS

The IASLC/ATS/ERS classification better discriminates AIS and MIA compared with current AJCC staging; however, integration suggests that these categories may be collectively classified in AJCC staging, based on similarly favorable outcomes and distinctive survival rates.

Clinical and radiographic differentiation of lung nodules caused by mycobacteria and lung cancer: a case-control study

Background

Lung nodules caused by mycobacteria can resemble lung cancer on chest imaging. The advent of lung cancer screening with low-dose Computed Tomography is accompanied by high false-positive rates, making it necessary to establish criteria to differentiate malignant from benign nodules.

Methods

We conducted a retrospective case–control study of 52 patients with mycobacterial lung nodules and 139 patients with lung cancer, diagnosed between 2010 and 2012. We compared clinical and radiographic characteristics to identify predictors of disease by univariate and multivariate analysis. The discriminatory power of maximum Standardized Uptake Values from Positron-Emission-Tomography was also evaluated.

Results

Several variables were correlated with a diagnosis of mycobacterial infection or lung cancer on univariate analysis. Such variable include smoking status and history, lesion size and imaging evidence of tree-in-bud opacities, lymphadenopathy or emphysema on computed tomography. Upon author consensus, the most clinically-relevant variables were selected to undergo multivariate analysis. A history of current or former smoking [OR 4.4 (95 % CI 1.2–15.6) and 2.7 (95 % CI 1.1–6.8), respectively P = 0.04] was correlated with diagnoses of lung cancer. Contrarily, the presence of tree-in-bud opacities was less likely to be correlated with a diagnosis of malignancy [OR 0.04 (95 % CI 0.0–1.0), P = 0.05]. Additionally, higher maximum standardized uptake values from positron emission tomography were associated with malignancy on multivariate analysis [OR 1.1 (95 % CI 1.0–1.2), P = 0.04]; but the accuracy of the values in differentiating between diseases was only 0.67 as measured by the area under the curve. Lesion size was not independently associated with diagnosis [OR 0.5 (95 % CI 0.2–1.2), (P = 0.12)].

Conclusions

Establishing the likelihood of malignancy for lung nodules based on isolated clinical or radiographic criteria is difficult. Using the variables found in this study may allow clinicians to stratify patients into groups of high and low risk for malignancy, and therefore establish efficient diagnostic strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1185-4) contains supplementary material, which is available to authorized users.

Influence of Software Tool and Methodological Aspects of Total Metabolic Tumor Volume Calculation on Baseline [18F]FDG PET to Predict Survival in Hodgkin Lymphoma

AIM

To investigate the respective influence of software tool and total metabolic tumor volume (TMTV0) calculation method on prognostic stratification of baseline 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography ([18F]FDG-PET) in newly diagnosed Hodgkin lymphoma (HL).

METHODS

59 patients with newly diagnosed HL were retrospectively included. [18F]FDG-PET was performed before any treatment. Four sets of TMTV0 were calculated with Beth Israel (BI) software: based on an absolute threshold selecting voxel with standardized uptake value (SUV) >2.5 (TMTV02.5), applying a per-lesion threshold of 41% of the SUV max (TMTV041) and using a per-patient adapted threshold based on SUV max of the liver (>125% and >140% of SUV max of the liver background; TMTV0125 and TMTV0140). TMTV041 was also determined with commercial software for comparison of software tools. ROC curves were used to determine the optimal threshold for each TMTV0 to predict treatment failure.

RESULTS

Median follow-up was 39 months. There was an excellent correlation between TMTV041 determined with BI and with the commercial software (r = 0.96, p<0.0001). The median TMTV0 value for TMTV041, TMTV02.5, TMTV0125 and TMTV0140 were respectively 160 (used as reference), 210 ([28;154] p = 0.005), 183 ([-4;114] p = 0.06) and 143 ml ([-58;64] p = 0.9). The respective optimal TMTV0 threshold and area under curve (AUC) for prediction of progression free survival (PFS) were respectively: 313 ml and 0.70, 432 ml and 0.68, 450 ml and 0.68, 330 ml and 0.68. There was no significant difference between ROC curves. High TMTV0 value was predictive of poor PFS in all methodologies: 4-years PFS was 83% vs 42% (p = 0.006) for TMTV02.5, 83% vs 41% (p = 0.003) for TMTV041, 85% vs 40% (p<0.001) for TMTV0125 and 83% vs 42% (p = 0.004) for TMTV0140.

CONCLUSION

In newly diagnosed HL, baseline metabolic tumor volume values were significantly influenced by the choice of the method used for determination of volume. However, no significant differences were found in term of prognosis.

Should preoperative chest computed tomography be performed in all patients with colorectal cancer?

AIM

This study evaluated the accuracy of chest computed tomography (CCT) in the preoperative staging of patients with potentially resectable colorectal cancer (CRC). An attempt was made to determine whether CCT has a significant influence on management and clinical outcome.

METHOD

A review was conducted of all preoperative CCTs and X-rays performed in patients submitted to elective resection of CRC at our institution between 2005 and 2012. All scans were revised by an independent radiologist who was unaware of the circumstances of each case. The findings were classified as benign, malignant or indeterminate. Patients were followed for at least 12 months after surgery to assess the clinical evolution of any lesion found on CCT and the oncological outcome.

RESULTS

Two hundred and twenty-three patients were included. The CCT showed normal or benign findings in 157 (70.4%) patients, a malignant lesion in 17 (7.6%), and an indeterminate lung lesion (ILL) in 49 (22%). Of the 30 patients with proven lung metastases, a plain X-ray detected lesions in only 11 (36.7%) patients. During the postoperative follow-up, 14 (28.6%) of the 49 patients with ILL demonstrated malignant progression of the lung lesions. Among all 223 patients, only six (2.7%) underwent lung resection.

CONCLUSION

CCT is superior to plain X-ray for the detection of lung metastases. Despite the medical and financial implications of preoperative CCT, only a small number of patients will eventually undergo lung resection. We call into question the role of routine CCT in the staging of patients with CRC. A more selective approach, reserving CT for patients at high risk of lung metastases, is suggested.

The role of ¹⁸F-FDG uptake features in the differential diagnosis of solitary pulmonary lesions with PET/CT

Background

The aim of this study is to evaluate the value of ¹⁸F-FDG uptake features in the diagnosis of solitary pulmonary lesions.

Methods

One hundred thirty-nine patients with solitary pulmonary lesions were divided into full uptake, circular uptake, multi-focus uptake, mild uptake, and no-uptake groups according to the uptake features of ¹⁸F-FDG in solitary pulmonary lesions. The incidence of benign and malignant lesions and the false-positive and false-negative rates in each group were analyzed. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of the method using ¹⁸F-FDG uptake features combined with maximum standard uptake value (SUVmax) (SUV method) in the differential diagnosis of solitary pulmonary lesions were evaluated.

Results

There were 89 malignant and 50 benign lesions. (1) The malignant incidence of the full uptake group was 84.0 % (63/75), and there were significant differences when compared with the other groups except the circular uptake group (16/23) (all P = 0.0001). The benign incidence of the multi-focus and no-uptake groups was 83.3 % (10/12) and 82.4 % (14/17), respectively, and there were significant differences when compared with the full uptake and the circular uptake groups, respectively (all P < 0.05). The benign incidence of the mild uptake group was 58.3 % (7/12), and there were no significant differences when compared with the others except the full uptake group (all P > 0.05). No statistical significance was found between either two of the no-uptake, mild uptake, and multi-focus uptake groups (all P > 0.05). (2) In cases with SUVmax ≥2.5, the false-positive rate in the multi-focus uptake group was 83.3 % (10/12), which was significantly higher than in the full uptake (12/75) or circular uptake group (7/23) (all P < 0.05). In cases with SUVmax <2.5, the false-negative rates in the mild and no-uptake groups were 41.7 and 17.6 % (P = 0.218). (3) The sensitivity, specificity, accuracy, PPV, and NPV of the method using ¹⁸F-FDG uptake features combined with SUVmax and the single SUV method were 88.7 %/91.0 %, 62.0 %/42.0 %, 79.1 %/73.4 %, 80.6 %/73.6 %, and 75.6 %/72.4 %, respectively.

Conclusions

The method using uptake features of ¹⁸F-FDG combined with SUVmax can improve the diagnostic specificity and accuracy of solitary pulmonary lesions. The multi-focus uptake feature maybe a benign sign, which still needs more researches to confirm.

Clinical significance of dual-time-point 18F-FDG PET imaging in resectable non-small cell lung cancer

OBJECTIVE

The maximal standardized uptake value (SUVmax) of pulmonary lesions on dual-time-point (DTP) fluorodeoxyglucose positron emission tomography (FDG-PET) has been shown to be useful for differentiation between malignant and non-malignant pulmonary lesions, and also to be of value for intrathoracic nodal staging of non-small cell lung cancer (NSCLC). However, a few NSCLC lesions have been found to show decreased FDG uptake on delayed images, and the significance of this finding remains unknown.

PATIENTS AND METHODS

We conducted a retrospective review of the data of 284 patients with NSCLC who underwent DTP FDG-PET before surgery. Cases of adenocarcinoma in situ and minimally invasive adenocarcinoma were excluded, because these lesions show little FDG uptake. Each patient was scanned at 60 min (early acquisition; SUV-E) and 115 min (delayed acquisition; SUV-D) after the radiopharmaceutical injection. The intratumoral retention index (RI) of 18F-FDG was measured for each examination by the DTP method. Recurrence-free survival (RFS) was determined by the Kaplan-Meier method and compared in relation to the SUV-E, SUV-D, and RI by univariate and multivariate analysis using models including the clinico-pathological prognostic factors.

RESULTS

Of the 284 cases, the RI ≤ 0 was in 49 cases (17.3%). This group of patients showed lower values of SUV-E and SUV-D, a smaller tumor size, and a lower rate of lymphatic invasion or vascular invasion. It was particularly noteworthy that lymph node metastasis was not histopathologically confirmed in any of these patients. Univariate analysis identified the RI, SUV-E and SUV-D, besides age, tumor size, lymph node metastasis, and tumor differentiation grade as predictors of the RFS. On the other hand, multivariate analysis identified the RI and lymph node metastasis, but not the SUV-E and SUV-D, as independent predictors of the RFS.

CONCLUSIONS

This study demonstrated that DTP FDG-PET of the primary tumor in NSCLC can be useful to predict the RFS of the patients. In addition, this method may also be useful to predict the presence/absence of intrathoracic lymph node metastasis in these patients.

Radiologic Evaluation of Small Lepidic Adenocarcinomas to Guide Decision Making in Surgical Resection

BACKGROUND

The International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification of pulmonary adenocarcinomas identifies indolent lesions associated with low recurrence, superior survival, and the potential for sublobar resection. The distinction, however, is determined on the pathologic evaluation, limiting preoperative surgical planning. We sought to determine whether preoperative computed tomography (CT) characteristics could guide decisions about the extent of the pulmonary resection.

METHODS

We reviewed the preoperative CT scans for 136 patients identified to have adenocarcinomas with lepidic features on the final pathologic evaluation. The solid component on CT was substituted for the invasive component, and patients were radiologically classified as adenocarcinoma in situ, 3 cm or less with no solid component; minimally invasive adenocarcinoma, 3 cm or less with a solid component of 5 mm or less; or invasive adenocarcinoma, exceeding 3 cm or solid component exceeding 5 mm, or both. Analysis of variance, t test, χ(2) test, and Kaplan-Meier methods were used for analysis.

RESULTS

The radiologic classification identified 35 adenocarcinomas in situ (26%) and 12 minimally invasive (9%) and 89 invasive adenocarcinoma (65%) lesions. At a 32-month median follow-up, patient outcomes associated with the radiologic classification were similar to the pathologic-based classification: the radiologic classification identified 14 of 16 patients with recurrent disease and all 6 who died of lung cancer. In addition, patients with radiologic adenocarcinoma in situ and minimally invasive adenocarcinoma who underwent sublobar resections had no recurrence and 100% disease-free and overall survival at 5 years.

CONCLUSIONS

The radiologic classification of patients with lepidic adenocarcinomas is associated with similar oncologic and survival outcomes compared with the pathologic classification and may guide decision making in the approach to surgical resection.

The diagnostic yield of preoperative staging computed tomography of the thorax in colorectal cancer patients without hepatic metastases

BACKGROUND

National UK guidelines recommend preoperative computed tomography (CT) examination of the chest for all patients with colorectal cancer (CRC) as identification of thoracic metastatic disease may influence treatment plans. The diagnostic yield of this approach for patients without radiological evidence of hepatic metastases remains unclear. The aim of this study was to establish the impact upon treatment of chest CT examination for CRC patients without metastatic liver disease.

PATIENTS AND METHODS

All patients diagnosed with CRC without liver metastases disease between December 2006 and December 2013 in a single institution were identified from a prospectively recorded departmental database. Data collected included patient demographics, disease stage and chest CT findings.

RESULTS

There were 358 CRC patients (183 male, 175 female, median age 70 years, range 24-96 years) without liver metastases. Colon cancer accounted for 68% of cases with 32% of patients diagnosed with rectal cancer. The majority of patients (n=292, 81.6%) had no evidence of thoracic pathology during the study period. Lung metastases were identified in five (1.4%) patients, one of them subsequently diagnosed with benign pulmonary nodule. In 61 (17.0%) patients the lung nodules were classified as intermediate with only three subsequently reclassified as pulmonary metastases (n=1) or primary lung cancer (n=2).

CONCLUSION

In the absence of liver metastases, CRC rarely spreads to the lung. Consequently, preoperative chest CT examination for patients without evidence of liver metastases may not be necessary in the majority of patients. Future studies are required to identify patients at high risk for pulmonary metastases who may benefit from this preoperative investigation.

Noninvasive Differential Diagnosis of Pulmonary Nodules Using the Standardized Uptake Value Index

OBJECTIVES

We previously showed that the standardized uptake value (SUV) index, which was defined as the ratio of the maximum SUV of the tumor to mean SUV of the liver, was a surrogate marker of lung cancer aggressiveness. In this study of patients with pulmonary nodules (PNs), we explored whether the SUV index could be used to differentiate small malignant from small benign PNs.

METHODS

A total of 284 patients with solitary PNs ≤2 cm in size underwent positron emission tomography/computed tomography and surgery. The associations between pathological findings and clinical factors were evaluated.

RESULTS

The median SUV indices of lung cancer, metastatic PNs and benign nodules were 1.2, 1.5, and 0.6, respectively (P <0.01). A SUV index cut-off value of 1.2 was used to differentiate benign from malignant nodules. When patients were grouped according to SUV index cut-off values of <1.2 or ≥1.2, the following cases were false-negative: lung adenocarcinoma (P <0.01), kidney as primary site (P <0.01), and metastatic PNs with long disease-free survival (P = 0.02).

CONCLUSIONS

As a noninvasive diagnostic marker, the SUV index was found to be useful for differentiating benign from malignant small PNs.

Indeterminate pulmonary nodules in colorectal cancer

AIM: To investigate the clinicopathologic parameters of pulmonary metastasis in colorectal cancer (CRC) patients after lung operation of indeterminate pulmonary nodules (IPNs).

METHODS: From a prospective database of CRC patients, 40 cases that underwent lung operation between November 2008 and December 2012 for suspicious metastatic pulmonary nodules on chest computed tomography (CT) were enrolled. The decision to perform a lung operation was made if the patient met the following criteria: (1) completely resected or resectable primary CRC; (2) completely resectable IPNs; (3) controlled or controllable extrapulmonary metastasis; and (4) adequate general condition and pulmonary function to tolerate pulmonary operation. Lung operation was performed by a thoracic surgeon without CT-guided biopsy for pathologic confirmation.

RESULTS: A total of 40 cases of lung resection was performed in 29 patients. Five patients underwent repeated lung resection. The final pathology result showed metastasis from the CRC in 30 cases (75%) and benign pathology in 10 cases (25%). The primary tumor site was the rectum in 26/30 (86.6%) cases with pulmonary metastasis, but only 3/10 (30%) cases in the benign group had a primary rectal cancer (P = 0.001). Positron emission tomography (PET)-CT was performed for 22/30 (73.4%) patients in the lung metastasis group and for 6/10 (60.0%) patients in the benign group. PET-CT revealed hot uptake of ¹⁸fluorine 2-fluoro-2-deoxy-D-glucose with all IPNs in both groups. The group with pulmonary metastasis had a higher incidence of primary rectal cancer (P = 0.001), a more advanced tumor stage (P = 0.011), and more frequent lymphatic invasion of tumor cells (P = 0.005). Six cases with previous liver metastasectomy were present in the lung metastasis group. Serum carcinoembryonic antigen levels before lung operation were not elevated in any of the patients.

CONCLUSION: The stage and location of the primary tumor and tumor cell infiltration of lymphatics provide useful indicators for deciding on lung resection of IPNs in CRC.

Surveillance of the Remaining Nodules after Resection of the Dominant Lung Adenocarcinoma is an Appropriate Follow-Up Strategy

INTRODUCTION

Adenocarcinomas, commonly present as a dominant lesion (DL) with additional nodules in the ipsilateral or contralateral lung. We sought to determine the fate and management of the secondary nodules and to assess the risk of these nodules using the Lung CT Screening Reporting and Data System (Lung-RADS) criteria and the National Comprehensive Cancer Network (NCCN) Guidelines to determine if surveillance is an appropriate strategy.

METHODS

We retrospectively evaluated patients with lepidic growth pattern adenocarcinoma and secondary nodules from 2000 to 2013. Risk assessment of the additional lesions was completed with a simplified model of Lung-RADS and NCCN-Guidelines.

RESULTS

Eighty-seven patients underwent resection of 87 DLs (Group 1) concurrently with 60 additional pulmonary nodules (Group 2), while 157 non-DLs were radiologically surveyed over a median follow-up time of 3.2 years (Group 3). Malignancy was found in 29/60 (48%) nodules in Group 2. Whereas, only 9/157 (6%) of the lesions in Group 3 enlarged, 4 of which (2.5% of total) were found to be malignant, and then treated, while the remaining nodules continued surveillance. After applying the Lung-RADS and NCCN simplified models, nodules in Group 2 were at higher risk for lung cancer than those in Group 3.

CONCLUSION

In patients with lepidic growth pattern adenocarcinoma associated with multiple secondary nodules, surveillance of the remaining nodules, after resection of the DL, is a reasonable strategy since these nodules exhibited a slow rate of growth and minimal malignancy. In contrast, nodules resected from the ipsilateral lung at the time of the DL, harbor malignancy in 48%. Risk assessment models may provide a useful and standardized tool for clinical assessment of pulmonary nodules.