Low Standardized Uptake Value Research Articles

Association between the Preoperative Standard Uptake Value (SUV) and Survival Outcomes after Robotic-Assisted Segmentectomy for Resectable Non-Small Cell Lung Cancer (NSCLC).

Lung-sparing procedures, specifically segmentectomies and wedge resections, have increased over the years to treat early-stage non-small cell lung cancer (NSCLC). We investigate here the perioperative and long-term outcomes of patients who underwent robotic-assisted segmentectomy (RAS) at an NCI-designated cancer center and aim to show associations between the preoperative standard update value (SUV) to tumor stage, recurrence patterns, and overall survival. A retrospective analysis was performed on 166 consecutive patients who underwent RAS at a single institution from 2010 to 2021. Of this number, 121 robotic-assisted segmentectomies were performed for primary NSCLC, and a total of 101 patients were evaluated with a PET-CT scan. The SUV from the primary tumor was determined from the PET-CT. The clinical, surgical, and pathologic profiles and perioperative outcomes were summarized via descriptive statistics. Numerical variables were described as the median and interquartile range because all numerical variables were not normally distributed as assessed by the Shapiro-Wilk test of normality. Categorical variables were described as the count and proportion. Chi-square or Fisher's exact test was used for association. The main outcomes were overall survival (OS) and recurrence-free survival (RFS). Kaplan-Meier (KM) curves were constructed to visualize the OS and RFS, which were also stratified according to tumor histology, the pathologic stage, and standard uptake value. A log-rank test for the equality of survival curves was performed to determine significant differences between groups. The most common postoperative complications were atrial fibrillation (8.8%, 9/102), persistent air leak (7.84%, 8/102), and pneumonia (4.9%, 5/102). The median operative duration was 168.5 min (IQR 59), while the median estimated blood loss was 50 mL (IQR 125). The conversion rate to thoracotomy in this cohort was 3.9% (4/102). Intraoperative complications occurred in 2.9% (3/102). The median hospital length of stay was 3 days (IQR 3). The median chest tube duration was 3 days (IQR 2), but 4.9% (5/102) of patients were sent home with a chest tube. The recurrence for this cohort was 28.4% (29/102). The time to recurrence was 353 days (IQR 504), while the time to mortality was 505 days (IQR 761). The NSCLC patients were divided into the following two groups: low SUV (<5, n = 55) and high SUV (≥5, n = 47). Statistically significant associations were noted between SUV and the tumor histology (p = 0.019), tumor grade (p = 0.002), lymph-vascular invasion (p = 0.029), viscera-pleural invasion (p = 0.008), recurrence (p < 0.001) and the site of recurrence (p = 0.047). KM survival analysis showed significant differences in the curves for OS (log-rank p-value 0.0204) and RFS (log-rank p-value 0.0034) between the SUV groups. Robotic-assisted segmentectomy for NSCLC has reasonable perioperative and oncologic outcomes. Furthermore, we demonstrate here the prognostic implication of preoperative SUV to pathologic outcomes, recurrence-free survival, and overall survival.

Novel SPECT/CT biomarker in transthyretin cardiac amyloidosis: correlation with myocardial amyloid load and cardiac structure and function

Abstract Background Single photon emission computed tomography/computed tomography (SPECT/CT) with determination of standardized uptake value (SUV) allows quantification of cardiac amyloid deposition. Purpose We aimed to investigate the relationship between quantitative cardiac tracer uptake determined by SPECT/CT and myocardial amyloid load, as well as cardiac structure and function in patients with transthyretin amyloid cardiomyopathy (ATTR-CM), and to identify nuclear imaging biomarkers for monitoring disease progression. Methods ATTR-CM patients underwent [99mTc]-radiolabeled diphosphono-1,2-propanodicarboxylic acid ([99mTc]-DPD) scintigraphy and SPECT/CT imaging (n=40) with determination of SUV, as well as cardiac magnetic resonance imaging (CMR, n=25) and transthoracic echocardiography (TTE, n=40). Results We observed significant correlations (r, Pearson's correlation coefficient) between SUV retention index and myocardial amyloid load [CMR extracellular volume (ECV): r=0.565, p=0.004, Figure 1A], cardiac structure [CMR interventricular septum: r=0.409, p=0.042, Figure 1B; CMR left ventricular mass index: r=0.508, p=0.010, Figure 1C], longitudinal cardiac function [TTE left ventricular global longitudinal strain (LV GLS): r=0.531, p=0.003, Figure 1D; TTE right ventricular free wall longitudinal strain: r=0.470, p=0.024, Figure 1E; TTE left atrial reservoir strain (LASr): r=-0.434, p=0.038, Figure 1F] and cardiac biomarkers [N-terminal prohormone of brain natriuretic peptide (NT-proBNP): r=0.475, p=0.004; high-sensitive troponin T (hs-TnT): r=0.358, p=0.027]. ATTR-CM patients were divided into two cohorts based on the median (4.32 mg/dL) of SUV retention index (low SUV uptake cohort: ≤4.32 mg/dL, n=20; high SUV uptake cohort: &amp;gt;4.32 mg/dL, n=20). We observed significant between-cohort differences with respect to LV ejection fraction (low SUV uptake: 51.8% vs. high SUV uptake: 46.2%, p=0.045), LV GLS (-14.5% vs. -11.1%, p=0.001), LASr (11.6% vs. 7.1%, p=0.023), NT-proBNP (1300 pg/mL vs. 2786 pg/mL, p&amp;lt;0.001), hs-TnT (42.9 ng/L vs. 62.2 ng/L, p=0.016) and 6-min walk distance (440.1 m vs. 330.1 m, p=0.022). Conclusions Using quantitative SPECT/CT imaging, we demonstrated that SUV retention index correlates with myocardial amyloid load, cardiac structure and function, and cardiac biomarkers. Our data suggest that quantitative SPECT/CT imaging with determination of SUV retention index may be a valid tool to monitor disease progression in ATTR-CM patients.Figure 1

Combined Metabolic and Functional Tumor Volumes on [18F]FDG-PET/MRI in Neuroblastoma Using Voxel-Wise Analysis.

The purpose of our study was to evaluate the association between the [18F]FDG standard uptake value (SUV) and the apparent diffusion coefficient (ADC) in neuroblastoma (NB) by voxel-wise analysis. From our prospective observational PET/MRI study, a subcohort of patients diagnosed with NB with both baseline imaging and post-chemotherapy imaging was further investigated. After registration and tumor segmentation, metabolic and functional tumor volumes were calculated from the ADC and SUV values using dedicated software allowing for voxel-wise analysis. Under the mean of thresholds, each voxel was assigned to one of three virtual tissue groups: highly vital (v) (low ADC and high SUV), possibly low vital (lv) (high ADC and low SUV), and equivocal (e) with high ADC and high SUV or low ADC and low SUV. Moreover, three clusters were generated from the total tumor volumes using the method of multiple Gaussian distributions. The Pearson's correlation coefficient between the ADC and the SUV was calculated for each group. Out of 43 PET/MRIs in 21 patients with NB, 16 MRIs in 8 patients met the inclusion criteria (PET/MRIs before and after chemotherapy). The proportion of tumor volumes were 26%, 36%, and 38% (v, lv, e) at baseline, 0.03%, 66%, and 34% after treatment in patients with response, and 42%, 25%, and 33% with progressive disease, respectively. In all clusters, the ADC and the SUV correlated negatively. In the cluster that corresponded to highly vital tissue, the ADC and the SUV showed a moderate negative correlation before treatment (R = -0.18; p < 0.0001) and the strongest negative correlation after treatment (R = -0.45; p < 0.0001). Interestingly, only patients with progression (n = 2) under therapy had a relevant part in this cluster post-treatment. Our results indicate that voxel-wise analysis of the ADC and the SUV is feasible and can quantify the different quality of tissue in neuroblastic tumors. Monitoring ADCs as well as SUV levels can quantify tumor dynamics during therapy.

3D-OSEM versus FORE + OSEM: Optimal Reconstruction Algorithm for FDG PET with a Short Acquisition Time.

Objective In this study, we investigated the optimal reconstruction algorithm in fluorodeoxyglucose (FDG) positron emission tomography (PET) with a short acquisition time. Materials and Methods In the phantom study, six spheres filled with FDG solution (sphere size: 6.23-37 mm; radioactivity ratio of spheres to background = 8:1) and placed in a National Electrical Manufacturers Association phantom were evaluated. Image acquisition time was 15 to 180 seconds, and the obtained image data were reconstructed using each of the Fourier rebinning (FORE) + ordered subsets expectation-maximization (OSEM) and 3D-OSEM algorithms. In the clinical study, mid-abdominal images of 19 patients were evaluated using regions of interest placed on areas of low, intermediate, and high radioactivity. All obtained images were investigated visually, and quantitatively using maximum standardized uptake value (SUV) and coefficient of variation (CV). Results In the phantom study, FORE + OSEM images with a short acquisition time had large CVs (poor image quality) but comparatively constant maximum SUVs. 3D-OSEM images showed comparatively constant CVs (good image quality) but significantly low maximum SUVs. The results of visual evaluation were well correlated with those of quantitative evaluation. Small spheres were obscured on 3D-OSEM images with short acquisition time, but image quality was not greatly deteriorated. The clinical and phantom studies yielded similar results. Conclusion FDG PET images with a short acquisition time reconstructed by FORE + OSEM showed poorer image quality than by 3D-OSEM. However, images obtained with a short acquisition time and reconstructed with FORE + OSEM showed clearer FDG uptake and more useful than 3D-OSEM in the light of the detection of lesions.

18F]FEOBV positron emission tomography may not be a suitable method to measure parasympathetic denervation in patients with Parkinson's disease

IntroductionThe peripheral autonomic nervous system may be involved years before onset of motor symptoms in some patients with Parkinson's disease (PD). Specific imaging techniques to quantify the cholinergic nervous system in peripheral organs are an unmet need. We tested the hypothesis that patients with PD display decreased [18F]FEOBV uptake in peripheral organs – a sign of parasympathetic denervation. MethodsWe included 15 PD patients and 15 age- and sex matched healthy controls for a 70 min whole-body dynamic positron emission tomography (PET) acquisition. Compartmental modelling was used for tracer kinetic analyses of adrenal gland, pancreas, myocardium, spleen, renal cortex, muscle and colon. Standard uptake values (SUV) at 60–70 min post injection were also extracted for these organs. Additionally, SUVs were also determined in the total colon, prostate, parotid and submandibular glands. ResultsWe found no statistically significant difference of [18F]FEOBV binding parameters in any organs between patients with PD and healthy controls, although trends were observed. The pancreas SUV showed a 14% reduction in patients (P = 0.021, not statistically significant after multiple comparison correction). We observed a trend towards lower SUVs in the pancreas, colon, adrenal gland, and myocardium of PD patients with versus without probable REM sleep behavior disorder. Conclusion[18F]FEOBV PET may not be a sensitive marker for parasympathetic degeneration in patients with PD.

Imaging and biopsy of HIV-infected individuals undergoing analytic treatment interruption.

BackgroundHIV persistence during antiretroviral therapy (ART) is the principal obstacle to cure. Lymphoid tissue is a compartment for HIV, but mechanisms of persistence during ART and viral rebound when ART is interrupted are inadequately understood. Metabolic activity in lymphoid tissue of patients on long-term ART is relatively low, and increases when ART is stopped. Increases in metabolic activity can be detected by 18F-fluorodeoxyglucose Positron Emission Tomography (FDG-PET) and may represent sites of HIV replication or immune activation in response to HIV replication.MethodsFDG-PET imaging will be used to identify areas of high and low metabolic uptake in lymphoid tissue of individuals undergoing long-term ART. Baseline tissue samples will be collected. Participants will then be randomized 1:1 to continue or interrupt ART via analytic treatment interruption (ATI). Image-guided biopsy will be repeated 10 days after ATI initiation. After ART restart criteria are met, image-guided biopsy will be repeated once viral suppression is re-achieved. Participants who continued ART will have a second FDG-PET and biopsies 12–16 weeks after the first. Genetic characteristics of HIV populations in areas of high and low FDG uptake will be assesed. Optional assessments of non-lymphoid anatomic compartments may be performed to evaluate HIV populations in distinct anatomic compartments.Anticipated resultsWe anticipate that PET standardized uptake values (SUV) will correlate with HIV viral RNA in biopsies of those regions and that lymph nodes with high SUV will have more viral RNA than those with low SUV within a patient. Individuals who undergo ATI are expected to have diverse viral populations upon viral rebound in lymphoid tissue. HIV populations in tissues may initially be phylogenetically diverse after ATI, with emergence of dominant viral species (clone) over time in plasma. Dominant viral species may represent the same HIV population seen before ATI.DiscussionThis study will allow us to explore utility of PET for identification of HIV infected cells and determine whether high FDG uptake respresents areas of HIV replication, immune activation or both. We will also characterize HIV infected cell populations in different anatomic locations. The protocol will represent a platform to investigate persistence and agents that may target HIV populations.Study protocol registrationIdentifier: NCT05419024.

Utilization of the lymph node-to-primary tumor ratio of PET standardized uptake value and circulating Epstein–Barr virus DNA to predict distant metastasis in nasopharyngeal carcinoma

Background and purposeTo determine the clinical impact of integrating Epstein–Barr virus (EBV) DNA and lymph node-to-primary tumor ratio (NTR) of positron emission tomography (PET) standardized uptake value (SUV) in predicting distant metastasis, such as distant metastasis-free survival (DMFS), in patients with nasopharyngeal carcinoma (NPC). Materials and methodsWe retrospectively reviewed patients diagnosed with non-disseminated NPC between 2010 and 2017. The optimal cut-off values of EBV DNA and SUV NTR were determined using receiver operating characteristic analysis. The prognostic values of SUV NTR and EBV DNA on DMFS and overall survival were evaluated using the Kaplan–Meier method. Univariate and multivariable analyses were performed using the Wald Chi-squared test and Cox proportional hazards regression, respectively. ResultsA total of 488 patients were included in the analysis. The median follow-up period was 61.6 months. The optimal cut-off values of EBV DNA and SUV NTR were 3377.5 copies per mL and 0.64, respectively. The five-year DMFS for patients with high vs low EBV DNA and SUV NTR levels were 64.9% vs 86.6% (p < 0.001) and 78.7% vs 87.4% (p = 0.021), respectively. In subgroup analysis, the high-risk group with high levels of pretreatment EBV DNA and SUV NTR had worse DMFS in either American Joint Committee on Cancer (AJCC) stage I–III or IVA–B (p = 0.001 and <0.001, respectively). Univariate and multivariable analyses showed the statistical significance of EBV DNA, SUV NTR, and their composite in DMFS (p < 0.001 for EBV DNA; p = 0.022 for SUV NTR; p < 0.001 for their composite). ConclusionThis study showed that EBV DNA and SUV NTR have independent and additive values as prognosticators for distant metastasis in patients with NPC, suggesting that these two individual factors, except the AJCC staging system, should be included in future studies.

Efficacy of Pre-operative 18F-FDG PET/CT in Prognostic Prediction in Patients With Renal Cell Carcinoma

Background/Aim: This study analyzed the parameters provided by preoperative 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for prognostic prediction of renal cell carcinoma (RCC). Patients and Methods: FDG-PET/CT data from 66 clear cell RCC and 19 non-clear cell RCC cases between January 2015 and October 2018 were reviewed retrospectively. We compared the two groups according to recurrence/metastasis to determine prognosis-influencing factors. Multivariate Cox hazard regression models were constructed to evaluate factors potentially predicting disease-free survival (DFS) after adjustment for confounders. DFS was then compared between groups. Results: Standardized uptake values (SUV) of the PET/CT scan were independent predictors of prognosis after adjusting for confounders. RCC cases were divided into two groups by optimal cut-off values. Differences between DFS percentages in high and low SUV groups were significant. Similar results were obtained in clear cell RCC groups. Conclusion: Increased SUV of the PET/CT scan are significant predictors of worse prognoses in patients with surgically resected RCC.

The Overlap Index: A new means for early detection of serial tau PET signal change

AbstractBackgroundIn longitudinal tau (flortaucipir) positron emission tomography (PET), a reliable method to detect a tau accumulation while minimizing a random variability is crucial. Variability can be a problem especially in the early stages of tau pathology in which only small regions and low levels of accumulation may exist relative to the range of random noise fluctuation.MethodWe recruited 76 participants who had serial scans for a total of 234 tau PET scans. In this cohort we tested a PET signal measurement method we developed called the “overlap index” (OI). The OI was calculated by identifying voxels that have elevated tau PET signal that overlap on two successive tau PET scans in the same participant (Figure 1). This analysis procedure tests the hypothesis that voxel‐wise, elevated‐uptake consistency might be more sensitive for early detection of tau tangles than standard ROI based measures. We compared OI to ROI based measures for early detection of increasing tau PET signal and detection clinical progression. A meta ROI used in this analysis included the amygdala, entorhinal cortex, fusiform, parahippocampal, and inferior temporal and middle temporal gyri.ResultOI showed regional progression of tau in the temporal lobe followed by increases throughout the brain at relatively low standardized uptake value ratio (SUVr) levels (Figure 2A and B). The topographical pattern of OI was in agreement in some respects with the sequential appearance of tau aggregation (Figure 2B and C). The high‐OI group (OI&gt;0.5) had a significantly higher ΔSUVr compared to the low‐OI group (OI&lt;0.5) (Figure 3A and B). OI identified subjects that did or didn’t have tau accumulation within meta SUVr subgroups even when below the meta ROI SUVr threshold. OI was associated with early clinical disease stage progression vs meta‐ROI SUVr measures (Figure 3C‐E).ConclusionIn this study, we found that OI tau PET measurement was able to quantify voxel‐wise consistency using a set of serial scans. OI may detect earlier tau tangle accumulation and earlier disease progression than standard SUVr measurements in tau PET.

Radiomic Phenotypes of High and Low Lesion SUV Components for the Prediction of Refractory Disease in Hodgkin's Lymphoma Patients Treated with ABVD Based Therapy

Background: Hodgkin's lymphoma (HL) is a curable malignancy. However, some patients are refractory to frontline therapy. Early prediction of response to frontline therapy could identify patients who may benefit from more intensive therapy. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has an established role in the management of HL. Radiomic features provide a way of quantifying imaging phenotypes and have shown promising results as predictors of outcomes in different lymphomas. Furthermore, great interest has been focused on the heterogeneity of standardized uptake value (SUV) within a single lesion. Since high SUV component (HSc) and low-SUV component (LSc) regions within a single lesion may be associated with different phenotypical characteristics, the radiomic analysis for each regional SUV component may provide a more complete description of lesions. Therefore, we proposed and evaluated new descriptors to quantify the image phenotypes based on HSc and LSc of lesions in HL.Methods: A total of 61 patients with HL of all stages who were seen at MD Anderson Cancer Center between 2016 and 2020 and had analyzable pre-treatment PET/CT were selected. All patients received standard of care ABVD or AVD regimens with or without radiation (Table 1A). Pre-treatment PET/CT scans were analyzed, and HL lesions were semi-automatically segmented using MIM 7 (Cleveland, OH) based on a SUV max threshold of 2.5. Manual edits were made and reviewed by a nuclear medicine physician and a lymphoma specialist. A total of 110 radiomic features were extracted from the segmented lesions in CT and PET using the open-source package of ‘PyRadiomics’ (Table 1B).Detailed description and algorithms of the extracted radiomics features are available at https://pyradiomics.readthedocs.io/en/latest/features.html. Additionally, each lesion was partitioned into HSc and LSc based on a cutoff value of 3 times the liver SUV mean (Figure A). The ratio of features between SUV components (HSc, LSc) and the lesion area was calculated. Furthermore, the feature difference between HSc and LSc was obtained.The maximum, minimum, average, and standard deviation of the radiomic features within multiple lesions were computed to reveal the distribution of features. A sequential forward feature selection was applied to select the significant features for building a logistic regression model, to predict refractory disease according to Lugano criteria. Two logistic regression models were constructed for early and advanced stage patients. Quantitative measures, namely metabolic tumor volume (MTV), total lesion glycolysis (TLG), and SUV max were measured for comparison. The leave-one-out-cross-validation (LOOCV) was applied to yield the receiver-operator-characteristics curve; the area under the curve (AUC) was then computed to evaluate the performance of the proposed model compared to quantitative measurements using DeLong's test.Results: The average of small dependence high gray level emphasis (GLDM) from PET, the difference of major axis length between high- and low- SUV component from PET, and the difference of 10th Percentile (histogram) between high- and low- SUV component from PET were selected for identifying the refractory disease in early stage lesions; the maximum of correlation (GLCM) from PET, SD of small dependence emphasis (GLDM) from PET, and SD of the inverse difference moment normalized (GLCM) from PET were selected for identifying refractory disease in advanced stage lesions. Based on LOOCV, the proposed radiomics model achieved an AUC of 0.93 for refractory disease prediction, which was significantly superior to MTV (AUC, 0.66; P = 0.01), TLG (AUC, 0.64; P = 0.01), and SUV max (AUC, 0.61; P = 0.01) (Figure B)Conclusion: High and low SUV components-based radiomic model of PET/CT was potentially useful for upfront prediction of refractory HL. Validation in a larger cohort using different segmentation methods, inclusion of additional treatment subgroups, comparison to other predictors, and correlation with survival outcomes are underway. [Display omitted] DisclosuresAhmed: Seagen: Research Funding; Merck: Research Funding; Tessa Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Xencor: Research Funding. Steiner: BMS: Research Funding; Seattle Genetics: Research Funding; Rafael Pharmaceuticals: Research Funding. Pinnix: Merck Inc: Research Funding. Wang: Molecular Templates: Research Funding; The First Afflicted Hospital of Zhejiang University: Honoraria; Hebei Cancer Prevention Federation: Honoraria; Bayer Healthcare: Consultancy; Mumbai Hematology Group: Honoraria; Pharmacyclics: Consultancy, Research Funding; BioInvent: Research Funding; Celgene: Research Funding; Physicians Education Resources (PER): Honoraria; Miltenyi Biomedicine GmbH: Consultancy, Honoraria; Scripps: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Imedex: Honoraria; Dava Oncology: Honoraria; Epizyme: Consultancy, Honoraria; Clinical Care Options: Honoraria; BGICS: Honoraria; CAHON: Honoraria; VelosBio: Consultancy, Research Funding; Loxo Oncology: Consultancy, Research Funding; InnoCare: Consultancy, Research Funding; BeiGene: Consultancy, Honoraria, Research Funding; Anticancer Association: Honoraria; Genentech: Consultancy; AstraZeneca: Consultancy, Honoraria, Research Funding; CStone: Consultancy; Newbridge Pharmaceuticals: Honoraria; Juno: Consultancy, Research Funding; Acerta Pharma: Consultancy, Honoraria, Research Funding; Chinese Medical Association: Honoraria; Kite Pharma: Consultancy, Honoraria, Research Funding; Oncternal: Consultancy, Research Funding; DTRM Biopharma (Cayman) Limited: Consultancy; OMI: Honoraria; Moffit Cancer Center: Honoraria; Lilly: Research Funding.

The prediction of disease progression by 18Fluorodeoxyglucose-positron emission computed tomography/CT in patients with dermatomyositis and interstitial lung disease

To investigate the predictive value of [18F]fluorodeoxyglucose-positron emission computed tomography(PET)/CT for disease progression in patients with dermatomyositis (DM) and interstitial lung diseases (ILD). Sixty-seven DM patients who underwent [18F] FDG-PET/CT imaging were retrospectively analyzed from January 2012 to September 2017 at PLA General Hospital. Their clinical manifestations and imaging characteristics were recorded. Compared with those chronically progressed (C-ILD), patients with rapid progression (RP-ILD) had significantly higher erythrocyte sedimentation rate (ESR) and standardized uptake value (SUV) in lungs (P<0.05). In patients with RP-ILD, SUV in lungs was positively correlated with age, disease course, and ESR. Receiver operating characteristic curve analysis suggested that when lung SUV cut off value was 2.25, the sensitivity and specificity to predict disease progression was 77.8% and 72.8%, respectively. Old age, longer disease course, low creatine kinase level, higher ESR, and high SUV are prognostic factors for DM-associated ILD.

Clinical usefulness of 18F-FDG PET in patients with hepatocellular carcinoma undergoing surgical resection

The diagnosis and staging hepatocellular carcinoma (HCC) is important because of the different treatment methods and the prognosis. [18F]fludeoxyglucose positron emission tomography/computed tomography ([18F]FDG-PET/CT) has been suggested as a diagnostic modality in HCC. The aim of this study is to evaluate the accuracy of [18F]FDG-PET for staging of HCC after surgical resection and histological confirmation. We retrospectively collected data of 56 patients who underwent [18F]FDG-PET before surgical resection for HCC from March 2011 to May 2017. All of whom were suitable for resection by conventional HCC staging. The results of maximal standardized uptake value (SUVmax) was compared with histological confirmation. A larger tumor size was related with a higher SUV (≥ 4.9) and also serum alpha-feto protein was associated with SUV. The recurrence rate was higher in patients with a higher SUV and the patients with lower SUV had better survival rate. HCC, [18F]fludeoxyglucose positron emission tomography, standardized uptake value (SUV).

PET-CT Invisible Diffuse Large B-Cell Lymphoma Features a Silent B-Cell Receptor Signaling

Background:18F-fluorodeoxyglucose (FDG) positron emission tomography with computed tomography (PET-CT) has been widely used in lymphoma patients for diagnosis, staging, assessment of response and surveillance. And the standardized uptake value (SUV), a commonly used indicator in PET-CT scan, can quantitatively reflect the glucose uptake and glycolysis of the tumor. Diffuse large B-cell lymphoma (DLBCL), one of the most common subtypes of aggressive lymphomas, is supposed to exhibit high standardized uptake value (SUV) in 18F-FDG PET-CT due to high rate of glucose (18F-FDG) uptake and high level of glycolysis. Nevertheless, PET-CT “invisible” DLBCL cases have also been described, which featuring a relatively low 18F-FDG uptake denoted by low SUV. Herein, we analyzed this subgroup of under-estimated disease.Methods: Nineteen cases each with PET-CT “invisible” (PET-CTi) and PET-CT “visible” (PET-CTv) de novo DLBCL were submitted for an immunohistochemical detection for the expression level of B-cell receptor (BCR) signaling-related molecules. Nine xenografts derived from BCR-dependent and BCR-independent DLBCL cell lines were further submitted for a small animal 18F-FDG PET-CT scanning and the following immunohistochemical detection for BCR signaling-related molecules.Results: The immunohistochemical expression level of pSYK (pY525/526), a key effector molecule for BCR signaling, was significantly lower in PET-CTi DLBCL tumor tissues compared with that in PET-CTv DLBCL cases (P <0.01). With regard to in vivo PET-CT experiment, the xenografts derived from BCR-independent DLBCL cell lines exhibited remarkable lower SUV level than those derived from BCR-dependent cell lines (P < 0.01). And BCR-independent DLBCL xenografts featured relatively lower expression level of pSYK compared with those BCR-dependent ones (P <0.01).Conclusions:18F-FDG PET-CT negative DLBCL features a silent BCR signaling and 18F-FDG PET-CT may be of use in evaluating BCR signaling status. DisclosuresNo relevant conflicts of interest to declare.

Non-invasive Standardised Uptake Value for Verification of the Use of Previously Validated Reference Region for [18F]Flortaucipir and [18F]Florbetapir Brain PET Studies

PurposeThe simplified reference tissue model (SRTM) is commonly applied for the quantification of brain positron emission tomography (PET) studies, particularly because it avoids arterial cannulation. SRTM requires a validated reference region which is obtained by baseline-blocking or displacement studies. Once a reference region is validated, the use should be verified for each new subject. This verification normally requires volume of distribution (VT) of a reference region. However, performing dynamic scanning and arterial sampling is not always possible, specifically in elderly subjects and in advanced disease stages. The aim of this study was to investigate the use of non-invasive standardised uptake value (SUV) approaches, in comparison to VT, as a verification of the previously validated grey matter cerebellum reference region for [18F]flortaucipir and [18F]florbetapir PET imaging in Alzheimer’s disease (AD) patients and controls.ProceduresDynamic 130-min [18F]flortaucipir PET scans obtained from nineteen subjects (10 AD patients) and 90-min [18F]florbetapir dynamic scans obtained from fourteen subjects (8 AD patients) were included. Regional VT’s were estimated for both tracers and were considered the standard verification of the previously validated reference region. Non-invasive SUVs corrected for body weight (SUVBW), lean body mass (SUL), and body surface area (SUVBSA) were obtained by using later time intervals of the dynamic scans. Simulations were also performed to assess the effect of flow and specific binding (BPND) on the SUVs.ResultsA low SUV corresponded well with a low VT for both [18F]flortaucipir and [18F]florbetapir. Simulation confirmed that SUVs were only slightly affected by flow changes and that increases in SUV were predominantly determined by the presence of specific binding.ConclusionsIn situations where dynamic scanning and arterial sampling is not possible, a low SUV(80–100 min) for [18F]flortaucipir and a low SUV(50–70 min) for [18F]florbetapir may be used as indication for absence of specific binding in the grey matter cerebellum reference region.

Radiofrequency ablation for treatment of thyroid follicular neoplasm with low SUV in PET/CT study

Objectives To evaluate the feasibility of radiofrequency ablation (RFA) on follicular neoplasm with low standard uptake value (SUV) in a Positron emission tomography (PET/CT) study. Methods From January 2018 to July 2019, 86 consecutive patients were diagnosed with follicular neoplasm. Of the patients, 28 with PET/CT scans were enrolled in this study. All patients received ultrasound, fine/core needle aspiration, and PET/CT scan prior to treatment. In accordance with previous studies, we recommended 6 patients who had follicular neoplasm with SUVmax ≥5 undergo surgical resection due to an elevated suspicion of malignancy. For 22 patients SUVmax <5, RFA was performed using the moving shot technique. Ultrasound was performed 6 to 12 months after each procedure. Results Statistically significant volume reductions during follow-up between values prior to RFA and 12 months post RFA were demonstrated (12.6 ± 20.9 vs. 2.4 ± 3.0 cm3, p < 0.001). Volume reduction ratios at 6–12 months (mean: 10.1 months) after RFA were 73.3% ± 17.7%. One patient presented with vocal cord palsy and recovered within 3 months after RFA. No postprocedural hypothyroidism occurred in the RFA patients. Conclusions By using PET/CT, we can select patients with low SUV follicular neoplasm. RFA offers a safe and feasible alternative treatment option for patients unsuitable or unwilling to undergo surgery. KEY POINTS By using positron emission tomography-computed tomography, we can distinguish low SUV follicular neoplasm for radiofrequency ablation. For low SUV follicular neoplasm, RF ablation offers a safe and effective alternative treatment option for patients unsuitable or unwilling to undergo surgery.

Focal cortical dysplasia imaging discrepancies between MRI and FDG-PET: Unique association with temporal lobe location

PurposeAlthough magnetic resonance imaging (MRI) and 18F-2-fluorodeoxyglucose-positron emission tomography (FDG-PET) are used for pre-surgical assessment of focal cortical dysplasia (FCD), they often disagree. This study aimed to identify factors that contribute to discrepancies in FCD imaging between MRI and FDG-PET. MethodsSixty-two patients (mean age, 18.9 years) with a FCD type I or II were retrospectively selected. These patients were visually categorized into two groups: 1) extent of PET abnormality larger than MRI abnormality and 2) vice versa or equivalent. Predictive factors of these two groups were analyzed by multivariate logistic regression. The extent of hypometabolic transient zone surrounding FCDs and their mean standardized uptake values were measured and compared by the Mann–Whitney U-test. ResultsFCDs were detected on MRI and PET in 46 and 55 patients, respectively, whereas no abnormality was detected in 4 patients. The PET hypometabolic areas were larger than the MRI abnormal areas in 26 patients (88 % in the temporal lobe), whereas the PET hypometabolic areas were equivalent or smaller than the MRI abnormal areas in 32 patients (69 % in the frontal lobe). The temporal lobe location was an independent predictor for differentiating the two groups (OR = 35.2, 95 % CI = 6.81–168.0, P < .001). The temporal lobe lesions had significantly wider transient zones and lower standardized uptake values than those in the other lobes (P < .001, both). ConclusionThe discrepancies between MRI and FDG-PET findings of FCD were associated with temporal lobe location.

Fluorodeoxyglucose-Positron Emission Tomography Predicts Bone Marrow Involvement in the Staging of Follicular Lymphoma.

Standard bone marrow biopsy (BMB) and bone involvement with follicular lymphoma (FL) on positron emission tomography (PET)/computed tomography (CT) both predict early clinical failure in FL. The key clinical question is whether PET/CT findings can obviate the need for BMB. The goal of this study was to determine the value of PET/CT in determining bone involvement in FL, using posterior iliac crest BMB as the gold standard. A total of 548 patients with newly diagnosed grade 1-3A FL were included. The presence, pattern, and location of bone involvement, spleen involvement, and standardized uptake values (SUVs) in the L3 vertebral body were recorded for all patients and compared with the BMB report. Excluding patients with focal bone lesions on PET/CT, the sensitivity and specificity of PET/CT in detecting bone or marrow involvement, compared with BMB, were 53% and 88%, respectively. The sensitivity and specificity of spleen involvement on PET/CT in predicting a positive BMB were 55% and 86%, respectively. An L3 SUVmax of less than 2.0 resulted in a negative predictive value (NPV) of 96% for marrow involvement on BMB; an L3 SUVmean below 1.4 resulted in an NPV of 100%. In newly diagnosed FL, PET/CT-detected bone and splenic involvement is highly specific for a positive BMB, and very low SUV values (<2.0 SUVmax and < 1.4 SUVmean ) in the lumbar spine have a high NPV for a negative BMB. Routine BMB may be obviated in these patients. BMB remains necessary to definitively exclude bone marrow involvement in a large majority of patients with a negative PET. Predicting early clinical failure in follicular lymphoma (FL) is important but difficult. Bone marrow involvement by FL is associated with early clinical failure, and determining this involvement is a key component of the initial staging. This study highlights that in certain patients, positron emission tomography/computed tomography is sufficient in determining bone or marrow involvement, without the need for a confirmatory bone marrow biopsy (BMB). An algorithm is provided based on these findings to help clinicians determine which patients would benefit from BMB and when it can be avoided.

Symmetry and spatial distribution of muscle glucose uptake in the lower limbs during walking measured using FDG-PET.

PurposeThis study aimed to elucidate whether muscle activity (in terms of glucose uptake) between the legs can be considered symmetrical during walking. Furthermore, we aimed to determine whether the [18F]-fluorodeoxyglucose was distributed heterogeneously throughout each muscle, and if so, whether areas of high uptake would be clustered.MethodsTen healthy participants walked on a treadmill at self-selected comfortable walking speed for a total of 90 minutes, 60 minutes before and 30 minutes after intravenous injection of 50 MBq [18F]-fluorodeoxyglucose. Thereafter, a positron emission tomography/computed tomography scan of the lower limb was acquired. Three-dimensional muscle contours of 78 (= 39x2) muscles of the left and right lower limb were semi-automatically determined from magnetic resonance imaging scans. After non-rigid registration, those muscle contours were used to extract [18F]-fluorodeoxyglucose uptake from the positron emission tomography scans.ResultsLarge asymmetries were observed in the lower leg muscles (e.g. median absolute asymmetry index of 42% in the gastrocnemius medialis) and in the gluteus minimus (30% asymmetry) and gluteus medius (15% asymmetry), whereas the uptake in the thighs was relatively symmetrical between the limbs (<6% asymmetry). These were not related to limb-dominance nor to inter-limb differences in muscle volume. The [18F]-fluorodeoxyglucose distribution was not distributed normally; most voxels had a relatively low standardized uptake value, and a minority of voxels had a relatively high standardized uptake value. The voxels with higher [18F]-fluorodeoxyglucose uptake were distributed heterogeneously; they were clustered in virtually all muscles.ConclusionThe findings in this study challenge the common assumption of symmetry in muscle activity between the limbs in healthy subjects. The clustering of voxels with high uptake suggests that even in this prolonged repetitive task, different spatial regions of muscles contribute differently to walking than others.

Expanding the Spectrum of Ciliated Muconodular Papillary Tumor of the Lung: A Case Showing Nonpapillary and Purely Glandular Morphology

Abstract We report an unusual case of a subpleural bronchiolar/glandular proliferation in a 76-year-old Hispanic woman with microscopic features reminiscent of those of the so-called ciliated muconodular papillary tumor (CMPT). The lesion presented radiologically as a solitary subpleural nodule measuring 2.7 × 1.2 cm with low standard uptake value (SUV) of 1.4. Microscopically, it was circumscribed but unencaspulated and consisted of mucous-filled spaces lined by cytologically bland cuboidal to low columnar cells, including goblet cells and ciliated epithelium, with underlying nodular collections of basaloid cells. The lining cells stained diffusely for CK7 but only focally for TTF-1 and CEA, whereas the basal cells expressed CK5/6. Ki-67 showed a proliferative index of less than 1%. Target gene mutation analysis with a 50-cancer-related-gene panel using next-generation sequencing showed the bronchiolar proliferation to harbor an EGFR in frame exon 20 insertion mutation with 30% allele frequency, which supports a neoplastic diagnosis. Accordingly, given the mutually exclusive nature of driver mutations, a BRAF V600E mutation was absent by both immunohistochemical and next-generation sequencing analysis. Microscopic evidence of metastatic spread was not seen in 8 regional lymph nodes examined. Given the histomorphology and immunohistochemical findings, the mutational profile and the reported heterogeneous microscopic patterns of CMPTs, including glandular component, we suggest the tumor herein described be a glandular variant of CMPT. We therefore suggest that the term ciliated muconodular tumor may be more appropriate for this group of lesions.

Significance of incidental intra-articular and peri-articular FDG avid foci on PET/CT.

Positron emission tomography/computed tomography (PET/CT) is a useful imaging adjunct in patients with sarcoma. Intra-articular and peri-articular 18F-fluoro-2-deoxy-D-glucose (FDG) avid lesions are often discovered incidentally. To describe the etiology, appearance, and standardized uptake values (SUV) of incidentally detected FDG avid intra-articular and peri-articular foci in patients with sarcoma. The institutional sarcoma database between November 2011 and November 2016 was retrospectively reviewed. Patients were included if a PET/CT scan was performed and an FDG avid intra-articular or peri-articular focus was found that was distinct from the primary sarcoma. The majority of FDG avid foci represented benign, non-physiologic conditions such as osteoarthritis, enthesopathy, bursitis, and post-surgical changes. Six patients each had radiographic features consistent with tenosynovial giant cell tumor (TSGCT) and metastatic disease, respectively. Lower SUV, bilateral findings, and the absence of metastatic disease elsewhere were associated with benign etiologies. There was a statistically significant difference between the mean SUV measured in patients with TSGCT and those with benign, non-physiologic conditions ( P < 0.001). The difference between the benign, non-physiologic cohort and the cohort with widespread metastatic disease did not reach statistical significance ( P = 0.07). In patients with soft-tissue or osseous sarcomas, isolated FDG avid intra-articular or peri-articular foci without additional metastatic lesions likely represent benign processes. Isolated intra-articular or peri-articular foci with significantly elevated SUV measurements were favored to represent TSGCT in this series.