Development and validation of a preoperative CT­based radiomics nomogram to differentiate tuberculosis granulomas from lung adenocarcinomas: an external validation study.

BACKGROUND: An accurate and non-invasive approach is urgently needed to distinguish tuberculosis granulomas from lung adenocarcinomas. This study aimed to develop and validate a nomogram based on contrast enhanced-compute tomography (CE-CT) to preoperatively differentiate tuberculosis granuloma from lung adenocarcinoma appearing as solitary pulmonary solid nodules (SPSN). METHODS: This retrospective study analyzed 143 patients with lung adenocarcinoma (mean age: 62.4 ± 6.5 years; 54.5% female) and 137 patients with tuberculosis granulomas (mean age: 54.7 ± 8.2 years; 29.2% female) from two centers between March 2015 and June 2020. The training and internal validation cohorts included 161 and 69 patients (7:3 ratio) from center No.1, respectively. The external testing cohort included 50 patients from center No.2. Clinical factors and conventional radiological characteristics were analyzed to build independent predictors. Radiomics features were extracted from each CT-volume of interest (VOI). Feature selection was performed using univariate and multivariate logistic regression analysis, as well as the least absolute shrinkage and selection operator (LASSO) method. A clinical model was constructed with clinical factors and radiological findings. Individualized radiomics nomograms incorporating clinical data and radiomics signature were established to validate the clinical usefulness. The diagnostic performance was assessed using the receiver operating characteristic (ROC) curve analysis with the area under the receiver operating characteristic curve (AUC). RESULTS: One clinical factor (CA125), one radiological characteristic (enhanced-CT value) and nine radiomics features were found to be independent predictors, which were used to establish the radiomics nomogram. The nomogram demonstrated better diagnostic efficacy than any single model, with respective AUC, accuracy, sensitivity, and specificity of 0.903, 0.857, 0.901, and 0.807 in the training cohort; 0.933, 0.884, 0.893, and 0.892 in the internal validation cohort; 0.914, 0.800, 0.937, and 0.735 in the external test cohort. The calibration curve showed a good agreement between prediction probability and actual clinical findings. CONCLUSION: The nomogram incorporating clinical factors, radiological characteristics and radiomics signature provides additional value in distinguishing tuberculosis granuloma from lung adenocarcinoma in patients with a SPSN, potentially serving as a robust diagnostic strategy in clinical practice.

Lung Lesions: Differential Diagnoses Beyond Cancer.

BACKGROUND Lung cancer is the most common malignant neoplasm diagnosed worldwide. Early diagnosis and treatment are of great importance for patient's prognosis. A wide variety of pulmonary conditions display clinical and radiological presentation similar to that of lung cancer, and the awareness of their existence can help in making correct diagnoses. CASE REPORT This article presents a description of 4 patients with an insidious type of lesions mimicking pulmonary carcinomas. The first patient was referred to Department with a tumor-like lesion in the right lung. After CT of the chest and core-needle biopsy, the lesion turned out to be an ectopic thyroid tissue. The second patient reported a dry cough and weight loss. A lung nodule mass was revealed in chest CT and the patient was diagnosed with pulmonary tuberculoma. The remaining 2 patients, despite the suspicion of lung cancer, were subsequently diagnosed with a post-traumatic pleural hematoma and diffuse large B cell lymphoma. CONCLUSIONS Low-dose computed tomography of the chest plays a significant role in the diagnosis of newly detected lesions in the lungs. However, due to the similarity of the image of cancer to that of other diseases, the ultimate diagnosis should be based on the interpretation of full imaging diagnostic tests, clinical presentation, and histopathological examination of the material obtained from the lesion. Analysis of cases enables us to expand our understanding of the diseases that need to be considered in differential diagnosis of a patient with a detected tumor-like lesion in the lungs.

Integrating molecular and radiological screening tools during community-based active case-finding for tuberculosis and COVID-19 in southern Africa.

OBJECTIVES: To evaluate diagnostic yield and feasibility of integrating testing for TB and COVID-19 using molecular and radiological screening tools during community-based active case-finding (ACF). METHODS: Community-based participants with presumed TB and/or COVID-19 were recruited using a mobile clinic. Participants underwent simultaneous point-of-care (POC) testing for TB (sputum; Xpert Ultra) and COVID-19 (nasopharyngeal swabs; Xpert SARS-CoV-2). Sputum culture and SARS-CoV-2 RT-PCR served as reference standards. Participants underwent ultra-portable POC chest radiography with computer-aided detection (CAD). TB infectiousness was evaluated using smear microscopy, cough aerosol sampling studies (CASS), and chest radiographic cavity detection. Feasibility of POC testing was evaluated via user-appraisals. RESULTS: Six hundred and one participants were enrolled, with 144/601 (24.0%) reporting symptoms suggestive of TB and/or COVID-19. 16/144 (11.1%) participants tested positive for TB, while 10/144 (6.9%) tested positive for COVID-19 (2/144 [1.4%] had concurrent TB/COVID-19). Seven (7/16 [43.8%]) individuals with TB were probably infectious. Test-specific sensitivity and specificity (95% CI) were: Xpert Ultra 75.0% (42.8-94.5) and 96.9% (92.4-99.2); Xpert SARS-CoV-2 66.7% (22.3-95.7) and 97.1% (92.7-99.2). Area under the curve (AUC) for CAD4TB was 0.90 (0.82-0.97). User appraisals indicated POC Xpert to have 'good' user-friendliness. CONCLUSIONS: Integrating TB/COVID-19 screening during community-based ACF using POC molecular and radiological tools is feasible, has a high diagnostic yield, and can identity probably infectious persons.

Chest Radiograph Screening for Detecting Subclinical Tuberculosis in Asymptomatic Household Contacts, Peru.

The World Health Organization's end TB strategy promotes the use of symptom and chest radiograph screening for tuberculosis (TB) disease. However, asymptomatic early states of TB beyond latent TB infection and active disease can go unrecognized using current screening criteria. We conducted a longitudinal cohort study enrolling household contacts initially free of TB disease and followed them for the occurrence of incident TB over 1 year. Among 1,747 screened contacts, 27 (52%) of the 52 persons in whom TB subsequently developed during follow-up had a baseline abnormal radiograph. Of contacts without TB symptoms, persons with an abnormal radiograph were at higher risk for subsequent TB than persons with an unremarkable radiograph (adjusted hazard ratio 15.62 [95% CI 7.74-31.54]). In young adults, we found a strong linear relationship between radiograph severity and time to TB diagnosis. Our findings suggest chest radiograph screening can extend to detecting early TB states, thereby enabling timely intervention.

Mycobacterium tuberculosis y virus linfotrópico humano, una co-infección fatal / Mycobacterium tuberculosis and human lymphotropic virus, a fatal co-infection

La tuberculosis es una infección de alta incidencia en Latinoamérica. Su presentación como infección activa está determinada por factores de riesgo del hospedero. Comunicamos el caso clínico de una mujer joven que presentó una forma grave de tuberculosis pulmonar. Al explorar sus factores de riesgo se confirmó un estado de inmunosupresión profundo, causado por un linfoma de células T, asociada a una co-infección por virus linfotrópico T humano tipo 1. Se destacan los aspectos microbiológicos y de pronóstico de la co-infección de Mycobacterium tuberculosis y HTLV-1

Tuberculosis is a high-incidence infection in Latin America. Its presentation as an active infection is determined by risk factors in the host. We report the case of a young woman who presented a severe form of pulmonary tuberculosis. When exploring her risk factors, a profound state of immunosuppression was found, caused by T-cell lymphoma, associated with co-infection with human lymphotropic virus. Microbiological and prognostic aspects of Mycobacterium tuberculosis and HTLV-1 co-infection are highlighted.

Added value of spectral computed tomography quantitative parameters for differentiating tuberculosis-associated fibrosing mediastinitis from endobronchial lung cancer: initial results.

OBJECTIVE: The objective of this study was to explore the added value of spectral computed tomography (CT) parameters to conventional CT features for differentiating tuberculosis-associated fibrosing mediastinitis (TB-associated FM) from endobronchial lung cancer (EBLC). METHODS: Chest spectral CT enhancement images from 109 patients with atelectasis were analyzed retrospectively. These patients were divided into two distinct categories: the TB-associated FM group (n = 77) and the EBLC group (n = 32), based on bronchoscopy and/or pathological findings. The selection of spectrum parameters was optimized with the least absolute shrinkage and selection operator regression analysis. The relationship between the spectrum parameters and conventional parameters was explored using Pearson's correlation. Multivariate logistic regression analysis was used to build spectrum model. The spectrum parameters in the spectrum model were replaced with their corresponding conventional parameters to build the conventional model. Diagnostic performances were evaluated using receiver operating characteristic curve analyses. RESULTS: There was a moderate correlation between the parameters ㏒(L-AEFNIC) - ㏒(L-AEFC) (r= 0.419; p< 0.0001), ㏒(O-AEF40KeV) - ㏒(O-AEFC) (r= 0.475; p< 0.0001), [L-A-hydroxyapatite {HAP}(I)] - (L-U-CT) (r= 0.604; p< 0.0001), {arterial enhancement fraction (AEF) derived from normalized iodine concentration (NIC) of lymph node (L-AEFNIC), AEF derived from CT40KeV of bronchial obstruction (O-AEF40KeV), arterial-phase Hydroxyapatite (Iodine) concentration of lymph node [L-A-HAP(I)], AEF derived from conventional CT (AEFC), unenhanced CT value (U-CT)}. Spectrum model could improve diagnostic performances compared to conventional model (area under curve: 0.965 vs 0.916, p= 0.038). CONCLUSION: There was a moderate correlation between spectrum parameters and conventional parameters. Integrating conventional CT features with spectrum parameters could further improve the ability in differentiating TB-associated FM from EBLC.

Adapted generative latent diffusion models for accurate pathological analysis in chest X-ray images.

Respiratory diseases have a significant global impact, and assessing these conditions is crucial for improving patient outcomes. Chest X-ray is widely used for diagnosis, but expert evaluation can be challenging. Automatic computer-aided diagnosis methods can provide support for clinicians in these tasks. Deep learning has emerged as a set of algorithms with exceptional potential in such tasks. However, these algorithms require a vast amount of data, often scarce in medical imaging domains. In this work, a new data augmentation methodology based on adapted generative latent diffusion models is proposed to improve the performance of an automatic pathological screening in two high-impact scenarios: tuberculosis and lung nodules. The methodology is evaluated using three publicly available datasets, representative of real-world settings. An ablation study obtained the highest-performing image generation model configuration regarding the number of training steps. The results demonstrate that the novel set of generated images can improve the performance of the screening of these two highly relevant pathologies, obtaining an accuracy of 97.09%, 92.14% in each dataset of tuberculosis screening, respectively, and 82.19% in lung nodules. The proposal notably improves on previous image generation methods for data augmentation, highlighting the importance of the contribution in these critical public health challenges.

Endobronchial Tuberculosis in an HIV-positive Case.

INTRODUCTION: Tuberculosis is an opportunist infection that is fatal and most frequently seen in HIV-positive patients due to immunosuppression. Endobronchial lesions can portray symptoms in different ways. Endobronchial Tuberculosis is one of these lesions. CASE REPORT: An HIV-positive, untreated 26-year-old patient with fever, cough, and dyspnea consulted our clinic. In the chest X-ray taken, effusion on the right side and non-homogeneous density increase in the middle and upper lobes, bilaterally more prominent on the right side, were observed. Therefore, the patient underwent bronchoscopy because the CT (computerized tomography) showed mediastinal lymphadenopathy (LAP) and an endobronchial lesion in the left main bronchus. During bronchoscopy, a vegetative endobronchial lesion that causes obstruction in the left main bronchus was monitored. With the help of Pathology and PCR results, endobronchial tuberculosis was diagnosed. CONCLUSION: Even if Acid-alcohol-resistant Bacillus (ARB) is detected negative in patients who stop responding to antimicrobial treatment and are being monitored under radiological scanning, a distinctive diagnosis of endobronchial tuberculosis should be kept in mind while performing bronchoscopy.

A comparison of chest radiographic findings in human immunodeficiency virus-positive and -negative children with pulmonary tuberculosis.

AIM: To compare chest radiography (CXR) findings in human immunodeficiency virus (HIV)-positive and HIV-negative children who had microbiologically confirmed pulmonary tuberculosis (PTB). MATERIALS AND METHODS: Retrospective analysis of CXRs from children with known HIV status and microbiologically confirmed PTB (culture or GeneXpert Xpert MTB/RIF positive), who were hospitalised or seen at a primary healthcare centre over a 5-year period. Radiological findings were compared according to HIV and nutritional status. RESULTS: CXRs of 130 children were analysed from 35 (27%) HIV- positive and 95 (73%) HIV-negative children with confirmed PTB, median age 45.7 months (interquartile range [IQR] 18-81.3 months). CXR changes consistent with PTB were reported in 21/35 (60%) of HIV-positive and 59/95 (62%) of HIV-negative patients, (p=0.81). Normal CXR was identified in 3/35 (8.6%) of HIV-positive and 5/95 (5.3%) of HIV-negative patients (p=0.81). Airway compression was present in 3/35 (8.6%) of HIV-positive and 7/95 (7.4%) of HIV-negative patients (p>0.99). Overall, lymphadenopathy was identified in 42/130 (32.3%) of patients, 11/35 (31.4 %) were HIV-positive compared with 31/95 (32.6%) HIV-negative patients. Airspace consolidation was present in 60% of both HIV-positive (21/35) and HIV-negative patients (57/95). Pleural effusion was present in 2/35 (5.7 %) of HIV-negative and 9/95 (9.5 %) of HIV-negative patients. There were no statistically significant radiological differences by HIV group. CONCLUSION: There were no significant differences in the CXR findings between the HIV-positive and HIV-negative children with confirmed PTB.

Fast magnetic resonance imaging for diagnosing pulmonary tuberculosis in children: the sub-10-min unenhanced scan.

PURPOSE: In this study, we aimed to report the feasibility and quality of fast (unenhanced < 10-min duration) magnetic resonance imaging (MRI) for the detection of lymphadenopathy in non-sedated children with suspected tuberculosis (TB). MATERIAL AND METHODS: This was a prospective study that involved children (< 13 years of age) hospitalised at Red Cross Children's Hospital with suspected pulmonary TB who were referred for a fast MRI of the chest. The limited short-duration MRI protocol included coronal short tau inversion recovery (STIR) and axial diffusion-weighted imaging (DWI) sequences with additional axial STIR and axial and coronal T2 sequences if the patient was compliant. The scan time was capped at 10 min and a study was considered successfully completed when DWI and STIR images were obtained in axial planes. MRI quality was recorded as 'acceptable quality'; 'poor quality, but readable'; and 'non-diagnostic'. RESULTS: Of the 192 fast MRI protocol scans, 166 (86%) were successfully completed within the 10-min allotted scan period. There was no age or sex difference between successful and unsuccessful studies. The mean duration of successful scans was 6.5 min (standard deviation = 1.5 min, range = 4-10 min). CONCLUSION: Fast (sub-10-min scan) MRI is feasible for diagnosis of lymphadenopathy in non-sedated children in the setting of suspected TB, including those below 6 years of age.

Frequency of abnormal findings on chest radiograph after positive PPD in children and adolescents in an urban setting in the United States.

BACKGROUND: Chest radiographs (CXR) for tuberculosis (TB) screening in children are valuable in high-burden settings. However, less certain in low prevalence contexts. In the United States, positive PPD is sufficient to treat for "latent" TB, or TB infection in asymptomatic patients. OBJECTIVE: We sought to determine frequency of abnormal CXR findings after a positive purified protein derivative (PPD) test at a tertiary pediatric center in the United States. METHOD: A retrospective evaluation was conducted of patients (0-18 years) with a CXR after a positive PPD (e.g., known exposure, employment, migratory requirements or before immunosuppression) between 2011 and 2021. Clinical information, demographics, and reason for PPD were recorded from health record. CXRs were evaluated using initial report and by a pediatric radiologist with special interest in TB and 8 years of experience. RESULT: Of 485 patients, median [interquartile range (IQR)] age 8.5[3.3-14.4], abnormal CXRs were described in 5 (1%). Most common reasons for PPD included: close contact with someone with TB or with high risk for TB. Most patients 373 (76.9%) received treatment for latent TB, and 111 (22.9%) no treatment. One patient (0.2%) received treatment for active disease. Radiographic findings included isolated lymphadenopathy (n = 2), consolidation (n = 1), pleural fluid/thickening (n = 1) and a patient with lymphadenopathy and a calcified nodule (n = 1). CONCLUSION: In our experience, prevalence of chest radiographs findings for patients with positive PPD was very low. Moreover, no cases of severe disease were seen and those with abnormal findings would not merit treatment change under current WHO guidelines.

Chest X-ray as an alternative method of making a preliminary diagnosis in patients with susceptible or drug-resistant pulmonary tuberculosis.

Background: Making a preliminary diagnosis using X-ray methods for the study of resistant and resistant tuberculosis (TB) will help to make a preliminary diagnosis and determine further tactics for the treatment of TB, even with limited resources for microbiological diagnosis of drug resistance of TB. The present study was aimed at identifying chest X-ray differences between susceptible and resistant TB. Methods: A prospective cohort study of data from all consecutive patients with culture-confirmed pulmonary TB admitted during the year to the Kharkiv TB Dispensary No. 1 in Kharkiv, Ukraine. Results: One hundred and sixty-eight patients with lung TB were examined. Patients were divided into two groups: 1st patients with pulmonary TB with resistance of Mycobacterium tuberculosis (MTB) to at least isoniazid and rifampicin (resistant TB) and 2nd pulmonary TB with preserved susceptibility of MTB to anti-TB drugs (susceptible-TB). Patients of 1st group often had lesions in two lobes of the lungs 31.1% and one lung 43.3% versus 15.4% and 2.6% of patients with susceptible TB (P < 0.001). In addition, more than 3 cavities in the lungs 45.5% were significantly more often observed in patients with resistant TB versus 7.9%-the 2nd group (P < 0.001). Smaller cavities were observed in patients with susceptible TB up to 1.99 cm 74% versus 35.2% in 1st group (P < 0.001). We did not observe any significant radiological features depending on the right or left lung, as well as the lobar localization of the TB process. Conclusions: For resistant forms of TB, radiologically, a more widespread TB process in the lungs with the presence of a larger number of cavities and their larger size against a background of a more pronounced clinical picture and mycobacterium excretion than with susceptible TB is characteristic.

Comparison of chest radiograph findings in ambulatory and hospitalized children with pulmonary tuberculosis.

BACKGROUND: The diagnosis of childhood tuberculosis (TB) is, in many instances, solely reliant on chest radiographs (CXRs), as they are often the only diagnostic tool available, especially in TB-endemic areas. Accuracy and reliability of CXRs for detecting TB lymphadenopathy may vary between groups depending on severity of presentation and presence of parenchymal disease, which may obscure visualization. OBJECTIVE: To compare CXR findings in ambulatory versus hospitalized children with laboratory confirmed pulmonary TB versus other lower respiratory tract infections (LRTI) and test inter-rater agreement for these findings. MATERIALS AND METHODS: Retrospective review, by two pediatric radiologists, of CXRs performed on children < 12 years old referred for evaluation of LRTI with clinical suspicion of pulmonary TB in inpatient and outpatient settings. Each radiologist commented on imaging findings of parenchymal changes, lymphadenopathy, airway compression and pleural effusion. Frequency of imaging findings was compared between patients based on location and diagnosis and inter-rater agreement was determined. Accuracy of radiographic diagnosis was compared to laboratory testing which served as the gold standard. RESULTS: The number of enrolled patients was 181 (54% males); 69 (38%) were ambulatory and 112 (62%) were hospitalized. Of those enrolled, 87 (48%) were confirmed to have pulmonary TB, while 94 (52%) were other LRTI controls. Lymphadenopathy and airway compression were more common in TB patients than other LRTI controls, regardless of patient location. Parenchymal changes and pleural effusion were more common in hospitalized than ambulatory patients, regardless of patient diagnosis. Agreement for parenchymal changes was higher in the hospitalized group (kappa [κ] = 0.75), while agreement for lymphadenopathy (κ = 0.65) and airway compression (κ = 0.68) was higher in the ambulatory group. The specificity of CXRs for TB diagnosis (> 75%) was higher than the sensitivity (< 50%) for both ambulatory and hospitalized groups. CONCLUSION: Higher frequency of parenchymal changes among hospitalized children may conceal specific imaging findings of TB such as lymphadenopathy, contributing to the poor reliability of CXRs. Despite this, the high specificity of CXRs shown in our results is encouraging for continued use of radiographs for TB diagnosis in both settings.

Introducing a secondary segmentation to construct a radiomics model for pulmonary tuberculosis cavities.

PURPOSE: Accurate segmentation (separating diseased portions of the lung from normal appearing lung) is a challenge in radiomic studies of non-neoplastic diseases, such as pulmonary tuberculosis (PTB). In this study, we developed a segmentation method, applicable to chest X-rays (CXR), that can eliminate the need for precise disease delineation, and that is effective for constructing radiomic models for automatic PTB cavity classification. METHODS: This retrospective study used a dataset of 266 posteroanterior CXR of patients diagnosed with laboratory confirmed PTB. The lungs were segmented using a U-net-based in-house automatic segmentation model. A secondary segmentation was developed using a sliding window, superimposed on the primary lung segmentation. Pyradiomics was used for feature extraction from every window which increased the dimensionality of the data, but this allowed us to accurately capture the spread of the features across the lung. Two separate measures (standard-deviation and variance) were used to consolidate the features. Pearson's correlation analysis (with a 0.8 cut-off value) was then applied for dimensionality reduction followed by the construction of Random Forest radiomic models. RESULTS: Two almost identical radiomic signatures consisting of 10 texture features each (9 were the same plus 1 other feature) were identified using the two separate consolidation measures. Two well performing random forest models were constructed from these signatures. The standard-deviation model (AUC = 0.9444 (95% CI, 0.8762; 0.9814)) performed marginally better than the variance model (AUC = 0.9288 (95% CI, 0.9046; 0.9843)). CONCLUSION: The introduction of the secondary sliding window segmentation on CXR could eliminate the need for disease delineation in pulmonary radiomic studies, and it could improve the accuracy of CXR reporting currently regaining prominence as a high-volume screening tool as the developed radiomic models correctly classify cavities from normal CXR.

Pulmonary Tuberculosis with Elevated CEA and Positive PET-CT.

BACKGROUND: Pulmonary tuberculosis presenting as solitary pulmonary nodules in imaging is sometimes difficult to differentiate from lung cancer and is more likely to be misdiagnosed when accompanied by elevated CEA and positive PET-CT findings. METHODS: By reporting a case of misdiagnosed lung cancer, which was confirmed to be pulmonary tuberculosis by lung biopsy, a joint literature analysis was performed to raise clinicians' awareness of isolated nodules in the lung. RESULTS: With a series of ancillary tests, we initially considered the nodule to be malignant, and the lung biopsy pathology eventually confirmed pulmonary tuberculosis. CONCLUSIONS: When chest imaging suggests the presence of malignant features in solitary pulmonary nodules, invasive procedures can be performed appropriately to clarify the nature of the lesion. The diagnosis cannot be made blindly to ensure that no incorrect diagnosis is made nor wrong treatment given.

Increased FAPI Activity in Pulmonary Tuberculosis.

ABSTRACT: A 50-year-old man presented with cough and hemoptysis for 1 month. Chest CT showed an irregular mass in the right lung, with enlarged lymph nodes in the mediastinum and right hilum. These findings were suggestive of lung cancer with lymph node metastases. The patient was subsequently enrolled in a 68Ga-DOTA-FAPI-04 PET/CT clinical trial. 68Ga-DOTA-FAPI-04 PET/CT revealed a mass in the upper lobe of right lung, with intense tracer uptake. Meanwhile, PET/CT showed enlarged lymph nodes in the mediastinum and right hilum, with mild FAPI uptake. However, pathological examination confirmed the mass was tuberculous granuloma.

PET morphology helps distinguish solitary and solid pulmonary tuberculosis from non-small cell lung cancer.

OBJECTIVE: Solitary and solid pulmonary tuberculosis (PTB) and non-small cell lung cancer (NSCLC) can present overlapping imaging features, causing diagnostic dilemmas. Hence, this study aimed to identify positron emission tomography (PET) morphological features derived from fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) images for a better differential diagnosis. METHODS: Clinical records and 18F-FDG PET/CT images of 175 patients confirmed with PTB and 311 patients with NSCLC were retrospectively reviewed. Parameters including patient demographics, PET-derived morphological features and metabolic parameters, and CT-derived morphological features were investigated. Logistic regression analysis was performed to assess the independent predictive factors associated with PTB. RESULTS: PTB presented with more heterogeneous glucometabolism than NSCLC in PET imaging (50% vs 17%, P < 0.05), especially in lesions with a maximum diameter < 30 mm (39% vs. 5%, P < 0.05). NSCLC usually showed centric hypometabolism, whereas PTB more frequently presented with an eccentric metabolic pattern, mainly including piebald, half-side, lesser curvature, and greater curvature shapes. Multivariate logistic regression identified that glucometabolic heterogeneity, eccentric hypometabolism, smaller lesion size, calcification, satellite lesions, and higher CT value of the hypometabolic area were independently diagnostic factors for PTB. CONCLUSIONS: Morphological features derived from 18F-FDG PET images helped distinguish solitary and solid PTB from NSCLC.