Is it possible to differentiate pulmonary sarcoidosis in tumor patients and pulmonary lymphangitic carcinomatosis caused by extrapulmonary tumors on 18F-FDG PET/CT images?

PURPOSE: Pulmonary sarcoidosis (PS) and pulmonary lymphangitic carcinomatosis (PLC) can be complications in tumor patients, and both involve the pulmonary interstitium and have similar imaging findings. Our objective was to distinguish PS and PLC on 18F-FDG PET/CT images. MATERIAL AND METHODS: The authors reviewed 18F-FDG PET/CT data of PS and PLC, diagnosed based on histopathology and imaging, in patients with tumors from July 2015 to January 2023. Three independent readers performed a blinded comparative analysis of 18F-FDG PET/CT signs in all patients. A multivariate logistic regression model was used to establish a differential diagnosis model. RESULTS: A total of 114 patients were included in the study: 56 patients with PS (mean age, 56 ± 11 [SD] years; 10 men) and 58 patients with PLC caused by extrapulmonary tumors (mean age, 51 ± 11 [SD] years; 21 men). For PS, breast cancer and cervical cancer were the most common primary tumors. For PLC, breast cancer and gastric cancer were the most common extrapulmonary tumors. The model constructed using multivariate logistic regression consisted of five factors: area of lymph node involvement, bronchovascular bundle diffuse thickening, interlobular septal thickening, pleural effusion, and subpleural hypermetabolic activity. The area under the model characteristic curve was 0.973 (95% CI 0.925-0.994), with a sensitivity, specificity, and positive and negative likelihood ratios of 87.50%, 98.28%, 50.75 and 0.13 respectively. CONCLUSION: There are detailed differences in 18F-FDG PET/CT manifestations of PS in tumor patients and PLC caused by extrapulmonary tumors, and the constructed diagnostic model has high clinical application value in differentiating the two.

A Frequently Missed Pulmonary Infarction: Clinical and 18F-FDG PET/CT Manifestation of Hilar Tumor-Induced Pulmonary Infarction.

PURPOSE: This study aimed to summarize the clinical and 18F-FDG PET/CT manifestations of hilar tumor-induced pulmonary infarction. METHODS: A retrospective analysis was performed on patients with hilar masses who underwent FDG PET/CT scans between July 2015 and January 2021 and had complete clinical data. Pulmonary infarction was confirmed by concurrent chest CT and imaging follow-up or pathology. RESULTS: A total of 58 patients (mean age, 56 [SD, 13] years; 44 males) with 122 infarcts were included in the study. Hilar masses were mostly associated with small cell lung cancer (64%). The most common clinical manifestations were cough (64%) and hemoptysis (36%). Most patients (62%) had multiple pulmonary infarcts. The CT findings of pulmonary infarcts included the "Hampton hump" (48%) and patchy consolidation (52%). The density of infarcts included "bubbly consolidation" (61%) and "homogenous consolidation" (39%). The metabolic activity of 95 infarcts (78%) was higher than lung parenchyma, with the SUVmax of 3.3 (SD, 1.1). The metabolic patterns on PET/CT were "rim sign," "mismatch between PET and CT," and "no metabolism." Pulmonary vein involvement was found in 25 patients (43%), pleural effusion in 22 patients (38%), and the pleural curvilinear sign in 8 patients (14%). CONCLUSIONS: The clinical manifestations of hilar tumor-induced pulmonary infarction are not specific, and 18F-FDG PET/CT could be an effective diagnostic tool.

Sacral Insufficiency Fracture after Radiotherapy for Cervical Cancer: Appearance and Dynamic Changes on 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

Objective: With the increasing application of radiotherapy for cervical cancer, the incidence of sacral insufficiency fracture (SIF) is increasing gradually. Incorrect or untimely treatment caused by misdiagnosis may lead to serious adverse clinical consequences. This study retrospectively analyzed SIF caused by radiotherapy regarding the appearance and dynamic changes in 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (18F-FDG) positive emission tomography (PET)/computed tomography (CT) images to improve the understanding of SIF. Materials and Methods: We retrospectively examined cervical cancer patients who underwent pelvic radiotherapy and 18F-FDG PET/CT between January 2014 and January 2021. Comparative analysis of the imaging performance and follow-up data was conducted. In total, 38 patients with ages ranging from 28 to 81 years (mean age 59.2 ± 10.6 y, median age 56 y) participated in the study. The respective characteristics of the 38 patients were summarized, and diagnosis was confirmed by follow-up changes. Results: Twenty-five (65.8%) of the 38 patients suffered from unilateral SIF, and 13 (34.2%) suffered from bilateral SIF. After receiving radiotherapy, SIF first appeared in 3-42 months (median, 13 months). The main 18F-FDG PET/CT manifestations of SIF were increased bone density (35/38, 92.1%), anterior sacral fracture line (28/38, 73.7%), and diffuse or linear uptake patterns parallel to the sacroiliac joint (37/38, 97.3%), with the maximum standard uptake value (SUVmax) ranging from 1.8 to 5.9 (average, 3.1). Follow-up lasted 3-59 months (mean, 14 months). The main changes in SIF were increases in the bone density and high-density range and decreases in the FDG uptake intensity and hypermetabolism range. Three patients had secondary sacral or sacroiliac joint infection (3/38, 7.9%), and 3 patients had secondary fracture and/or pelvic deformation (3/38, 7.9%). Conclusions: 18F-FDG PET/CT is an effective technique for diagnosing SIF. A small fracture line in the anterior sacrum and diffuse or linear areas of high density or metabolism parallel to the sacroiliac joint were the characteristic features of SIF. The main changes in SIF were increases in the bone density and high-density range and decreases in the FDG uptake intensity and hypermetabolism range.

The Diagnostic Value of FDG PET/CT and Thin-Slice High-Resolution Chest CT in Pulmonary Intravascular Metastasis.

OBJECTIVE. Pulmonary intravascular metastasis is a special type of pulmonary metastasis of malignancies; however, few relevant studies have been performed. This study aimed to determine the characteristics of pulmonary intravascular metastasis and improve understanding of the disease by retrospective analysis of FDG PET/CT and thin-layer high-resolution CT (HRCT) imaging of the chest in patients with tumors. MATERIALS AND METHODS. We identified all patients who underwent FDG PET/CT at two hospitals between January 2016 and February 2019 and conducted a comparative analysis of HRCT and PET/CT images. In total, 84 patients (38 women and 46 men) ranging in age from 35 to 82 years old (mean age, 54.7 ± 14.5 [SD] years) participated in the study. Patient characteristics were summarized, and diagnosis was confirmed by chest CT or PET/CT follow-up. RESULTS. A total of 260 pulmonary intravascular metastases were found, which were classified as type I (no significant abnormality, n = 5), type II (abrupt and uneven thickening of the pulmonary vessel, n = 118), type III (simultaneous invasion of adjacent pulmonary vessel, n = 121), and type IV (large strip-shaped high-density mass, n = 16). The majority were located in peripheral pulmonary vessels (94.2% [245/260]). FDG up-take was increased in 252 lesions, and the mean SUVmax was 4.6 ± 2.5. CONCLUSION. The combination of PET/CT and chest HRCT is an effective approach for detecting pulmonary intravascular metastasis. The linear pattern of FDG uptake, abnormal pulmonary blood vessel morphology, and location (below the lung segment) are specific indicators for the diagnosis of pulmonary intravascular metastasis and should be recognized by clinicians and radiologists.

18F-FDG Positron-Emission Tomography/Computed Tomography Findings of Radiographic Lesions Suggesting Old Healed Pulmonary Tuberculosis and High-risk Signs of Predicting Recurrence: A Retrospective Study.

Pulmonary tuberculosis (PTB) is a common worldwide infection with high mortality and morbidity, especially in developing countries. This study analyzed PET/CT findings in tumor patients with radiographic lesions suggesting old healed pulmonary tuberculosis (OHPTB) and imaging follow-up to find and verify PET/CT signs that may predict tuberculosis recurrence. A retrospective analysis of the tumor patients was carried out. These patients underwent 18F-FDG PET/CT in our center from 2010 to 2018. Confirmation of tuberculosis recurrence was obtained by follow-up of morphological changes in old lesions by PET/CT or CT. In total, 238 patients with a complete medical history were included in the final study, and 22 patients experienced OHPTB recurrence. We found that the SUVmax of tuberculosis in PET/CT was significantly increased in the recurrence group compared to the non-recurrence group [5.00 (3.40, 7.30) vs. 1.10 (0.80, 1.30), P < 0.001]. The ROC curve showed good discrimination, with an AUC of 0.980, and a cut-off SUVmax value of 2.15 was identified (the sensitivity was 90.5%, the specificity was 97.2%, the positive predictive value was 76.0%, and the negative predictive value was 99.1%). Both the tumor and the anti-tumor treatment can cause the patient to be immunocompromised and might further cause the recurrence of OHPTB. Positive imaging on 18F-FDG PET can predict the recurrence of OHPPT. Although there might be a false positive, 18F-FDG PET can greatly narrow the monitoring range. A negative result on imaging has high reliability for eliminating the possibility of tuberculosis recurrence. PET/CT has important clinical significance in tuberculosis management in patients with concurrent OHPTB.

Genome Sequence of the Freshwater Yangtze Finless Porpoise.

The Yangtze finless porpoise (Neophocaena asiaeorientalis ssp. asiaeorientalis) is a subspecies of the narrow-ridged finless porpoise (N. asiaeorientalis). In total, 714.28 gigabases (Gb) of raw reads were generated by whole-genome sequencing of the Yangtze finless porpoise, using an Illumina HiSeq 2000 platform. After filtering the low-quality and duplicated reads, we assembled a draft genome of 2.22 Gb, with contig N50 and scaffold N50 values of 46.69 kilobases (kb) and 1.71 megabases (Mb), respectively. We identified 887.63 Mb of repetitive sequences and predicted 18,479 protein-coding genes in the assembled genome. The phylogenetic tree showed a relationship between the Yangtze finless porpoise and the Yangtze River dolphin, which diverged approximately 20.84 million years ago. In comparisons with the genomes of 10 other mammals, we detected 44 species-specific gene families, 164 expanded gene families, and 313 positively selected genes in the Yangtze finless porpoise genome. The assembled genome sequence and underlying sequence data are available at the National Center for Biotechnology Information under BioProject accession number PRJNA433603.

Prediction of the outcome of definitive chemoradiation by decrease in F-18 FDG uptake in nonsurgical esophageal squamous cell cancer.

PURPOSE: To analyze the predictive value of fluorine-18 fluorodeoxyglucose (F-18 FDG) uptake using positron emission tomography and computed tomography to assess the outcome of definitive chemoradiation in nonsurgical esophageal squamous cell carcinoma. MATERIALS AND METHODS: A retrospective review of 61 patients with clinical stage T1-4, N0/1, and M0 was performed. Chemoradiation included chemotherapy with fluorouracil plus cisplatin and irradiation with a total dose of 5600 to 6400 centigray (cGy). Positron emission tomography combined with computed tomography scans were acquired before and during the therapy. The correlation between a decrease in FDG uptake and 5-year progression-free survival (PFS) was analyzed by a receiver operating characteristic curve method to determine a cutoff value. A 5-year overall survival (OS), PFS, and cancer-specific survival (CSS) were evaluated by Kaplan-Meier method. RESULTS: The mean of standardized uptake value decreased significantly during chemoradiation (P = 0.001). Using 51% reduction of FDG uptake as a cutoff value provided a sensitivity of 76.9% and a specificity of 79.2% in predicting PFS (P = 0.000). The positive predictive value and negative predictive value were 50% and 95%, respectively. PFS, CSS, and OS were significantly different when grouped by this cutoff value (P < 0.05), and when dichotomized by stage T1-2 and T3-4 (P < 0.05), simultaneously with a decrease of 51% or more in FDG uptake. CONCLUSIONS: This study showed that a 51% decrease in FDG uptake during chemoradiation was a sensitive and accurate cut-point for predicting PFS. Stage T and decrease in FDG uptake were 2 independent predictive factors for 5-year PFS, CSS, and OS.

DNA repair gene XRCC1 polymorphisms and non-Hodgkin lymphoma risk in a Chinese population.

Genetic polymorphism in DNA repair genes may influence individual variation in DNA repair capacity, which may be associated with cancer risks. This hospital-based case-control study examined whether polymorphism in the DNA repair gene x-ray repair cross-complementing groups 1 (XRCC1 Arg194Trp [C-->T], Arg280His [G-->A], and Arg399Gln [G-->A]) played a role in susceptibility to non-Hodgkin's lymphoma (NHL) in the Chinese population. We genotyped these polymorphisms for 221 histopathologically confirmed NHL cases and 254 age- and sex-matched healthy control cases in China. No studied polymorphism alone was shown to be related to the risk of NHL or each histologic subtype of NHL. When stratified by smoking status, however, the XRCC1Arg399Gln variant genotypes (homozygotes and heterozygotes) were associated with a 3.0-fold risk of follicular lymphoma among heavy smokers (95% confidence interval: 1.16-7.82; P = 0.02). Further large-scale studies would confirm this association and clarify marginally significant trends in XRCC1 polymorphism combinations for an increased risk for NHL.