Maximum Standardized Uptake Value of 18F-deoxyglucose PET Imaging Increases the Effectiveness of CT Radiomics in Differentiating Benign and Malignant Pulmonary Ground-Glass Nodules

To investigate whether the maximum standardized uptake value (SUVmax) of 18F-deoxyglucose (FDG) PET imaging can increase the diagnostic efficiency of CT radiomics-based prediction model in differentiating benign and malignant pulmonary ground-glass nodules (GGNs). We retrospectively collected 190 GGNs from 165 patients who underwent 18F-FDG PET/CT examination from January 2012 to March 2020. Propensity score matching (PSM) was performed to select GGNs with similar baseline characteristics. LIFEx software was used to extract 49 CT radiomic features, and the least absolute shrinkage and selection operator (LASSO) algorithm was used to select parameters and establish the Rad-score. Logistic regression analysis was performed combined with semantic features to construct a CT radiomics model, which was combined with SUVmax to establish the PET + CT radiomics model. Receiver operating characteristic (ROC) was used to compare the diagnostic efficacy of different models. After PSM at 1:4, 190 GGNs were divided into benign group (n = 23) and adenocarcinoma group (n = 92). After texture analysis, the Rad-score with three CT texture features was constructed for each nodule. Compared with the Rad-score and CT radiomics model (AUC: 0.704 (95%CI: 0.562-0.845) and 0.908 (95%CI: 0.842-0.975), respectively), PET + CT radiomics model had the best diagnostic efficiency (AUC: 0.940, 95%CI: 0.889-0.990), and there was significant difference between each two of them (P = 0.001-0.030). SUVmax can effectively improve CT radiomics model performance in the differential diagnosis of benign and malignant GGNs. PET + CT radiomics might become a noninvasive and reliable method for differentiating of GGNs.

Clinical Significance and Prognostic Value of the Maximum Standardized Uptake Value of 18F-Flurodeoxyglucose Positron Emission Tomography–Computed Tomography in Colorectal Cancer

BackgroundThe role of 18F-flurodeoxyglucose (18F-FDG) positron emission tomography–computed tomography (PET/CT) in colorectal cancer (CRC) remains unclear. This study aimed to explore the association of the maximum standardized uptake value (SUVmax), a parameter of 18F-FDG PET/CT, with KRAS mutation, the Ki-67 index, and survival in patients with CRC.MethodsData of 66 patients with CRC who underwent 18F-FDG PET/CT was retrospectively collected in our center. The clinical significance of the SUVmax in CRC and the association of the SUVmax with KRAS mutation and the Ki-67 index were determined. A meta-analysis was conducted by a systematic search of PubMed, Web of Science, and CNKI databases, and the data from published articles were combined with that of our study. The association of the SUVmax with KRAS mutation and the Ki-67 index was determined using the odds ratio to estimate the pooled results. The hazard ratio was used to quantitatively evaluate the prognosis of the SUVmax in CRC.ResultsBy analyzing the data of 66 patients with CRC, the SUVmax was found not to be related to the tumor-node-metastasis stage, clinical stage, sex, and KRAS mutation but was related to the tumor location and nerve invasion. The SUVmax had no significant correlation with the tumor biomarkers and the Ki-67 index. Data of 17 studies indicated that the SUVmax was significantly increased in the mutated type compared with the wild type of KRAS in CRC; four studies showed that there was no remarkable difference between patients with a high and low Ki-67 index score regarding the SUVmax. Twelve studies revealed that the SUVmax had no significant association with overall survival and disease-free survival in CRC patients.ConclusionsBased on the combined data, this study demonstrated that the SUVmax of 18F-FDG PET/CT was different between colon and rectal cancers and associated with KRAS mutation but not the Ki-67 index; there was no significant association between the SUVmax and survival of patients with CRC.

PET-CT Quantitative Parameter Delta Suvmax As a Predictor of Early Relapse in Patients with Difuse Large B-Cell Lymphoma

Introduction: About one third of patients with diffuse large B-cell lymphoma (DLBCL) fail frontline treatment or have early relapse. Baseline quantitative parameters derived from positron emission computed tomography (PET/CT) at baseline may predict outcome in DLBCL patients. However, their prognostic value in interim scans is unclear. Recently, the role delta maximum standardized uptake value (ΔSUVmax) has been tested as a predictor of PFS. In this retrospective study we aimed to analyze the role of ΔSUVmax between baseline and interim PET-CT as a predictor of progression of disease within 1 year in DLBCL patients and, to compare this parameter to the standard validated method to evaluate disease response: Deauville scale (DS). Methods: This is a single-center retrospective cohort study from São Paulo, Brazil. We included patients with DLBCL who had baseline (b-PET) and interim (i-PET, after 2-3 cycles of treatment) PET-CTs and who have been treated with 6 cycles of R-CHOP given every 21 days. All PET-CTs were analyzed by the same physician and blinded for the clinical features. Delta maximum standardized uptake value (ΔSUVmax) was calculated by the difference in % between initial PET SUVmax and iPET SUVmax. The objective was to assess if ΔSUV performed better than Deauville scale (DS) in predicting early disease progression. Cut-off values were defined by receiver operating characteristic (ROC) analysis. Analysis was performed with Cox model. Model comparison was based on the lowest AIC. Results: A total of 83 patients with DLBCL were available for analyses. The median age was 60 years and 66% of patients had a germinal center B-Cell (GCB) phenotype. With median follow-up of 15 months, patients with a cut-off ΔSUVmax <85% had a higher risk of disease relapse (49% vs 2%, p<0.001) at 12 months (figure 1). Patients with DS >3 in the iPET were also at a higher risk of disease progression (p<0.001) (figure 2). The model with ΔSUVmax was better adjusted (AIC=86) than the one with DS (AIC=92). The median maximum uptake at baseline PET/CT, MYC and/or BCl2 expression were not predictive of relapse at 12 months. International prognostic index (IPI) was also predictive of relapse (p=0.003), but again performed poorer than ΔSUVmax (AIC=99). Discussion/Conclusion: We showed that ΔSUVmax quantitative PET-CT model has superior discriminatory power than the qualitative DS model and the clinical IPI. Although we have a small sample, this finding corresponds with PETAL trial, which also showed that the ΔSUVmax method is superior to the commonly used Deauville five-point scale to identify patients at high risk of treatment fails. Although, the ΔSUVmax cut-off value calculated in our study was 85%, while in the PETAL study a reduction off 66% in the baseline SUV was the considered cutoff. Maybe, combing ΔSUVmax method in a with DS and IPI can improve prognostic stratification and early identification of high risk DLBCL. The ΔSUVmax is an easily reproducible method, that can be easily assessed by PET-CT, differing from other quantitative measures like the total metabolic tumor volume. In conclusion, further validation in a large sample of patients should be performed before the incorporation of quantitative PET-CT methods in clinical practice however it is a promising prognostic marker. Figure 1 Figure 1. Disclosures Perini: Janssen: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Astra Zeneca: Honoraria, Speakers Bureau; MSD: Honoraria, Speakers Bureau.

Is It Possible to Establish a Reliable Correlation between Maximum Standardized Uptake Value of 18-Fluorine Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography and Histological Types of Non-Small Cell Lung Cancer? Analysis of the Italian VATS Group Database

Background. Although positron emission tomography/computed tomography, often integrated with 2-deoxy-2-[fluorine-18] fluorine-D-glucose (18F-FDG-PET/CT), is fundamental in the assessment of lung cancer, the relationship between metabolic avidity of different histotypes and maximum standardized uptake value (SUVmax) has not yet been thoroughly investigated. The aim of the study is to establish a reliable correlation between Suvmax and histology in non-small cell lung cancer (NSCLC), in order to facilitate patient management. Methods. We retrospectively assessed the data about lung cancer patients entered in the Italian Registry of VATS Group from January 2014 to October 2019, after establishing the eligibility criteria of the study. In total, 8139 patients undergoing VATS lobectomy were enrolled: 3260 females and 4879 males. The relationship between SUVmax and tumor size was also analyzed. Results. The mean values of SUVmax in the most frequent types of lung cancer were as follows: a) 4.88 ± 3.82 for preinvasive adenocarcinoma; b) 5.49 ± 4.10 for minimally invasive adenocarcinoma; c) 5.87 ± 4.18 for invasive adenocarcinoma; and d) 8.85 ± 6.70 for squamous cell carcinoma. Processing these data, we displayed a statistically difference (p < 0.000001) of FDG avidity between adenocarcinoma and squamous cell carcinoma. Moreover, by classifying patients into five groups based on tumor diameter and after evaluating the SUVmax value for each group, we noted a statistical correlation (p < 0.000001) between size and FDG uptake, also confirmed by the post hoc analysis. Conclusions. There is a correlation between SUVmax, histopathology outcomes and tumor size in NSCLC. Further clinical trials should be performed in order to confirm our data.