18F-fluorodeoxyglucose Uptake Research Articles

18F-fluorodeoxyglucose uptake in advanced gastric cancer correlates with histopathological subtypes and volume of tumor stroma

PurposeThe aim of this study was to investigate the correlation between preoperative 18F-fluorodeoxyglucose (FDG) uptake and histological subtypes, amount of tumor stroma in advanced gastric cancer (GC), and clinical outcomes. MethodsWe evaluated 56 patients (male/female, 42:14; mean age, 69 years) with advanced GC who underwent surgical resection at our institution and positron emission tomography–computed tomography with 18F-FDG prior to surgery. We used the maximum standardized uptake value (SUVmax) of the tumor and the tumor-to-liver ratio (TLR) of the SUVmax for the analysis. The SUVmax and TLR correlated with histological subtypes, immunohistochemistry (IHC) for CD34, and recurrence-free survival (RFS). Tumor stroma in GC was evaluated by CD34 expression. GCs were classified according to the Lauren and World Health Organization (WHO) classifications. ResultsThe average FDG uptakes (SUVmax) were 4.17% and 14.04% in diffuse and intestinal type GCs, respectively, according to the Lauren classification, and 4.17%, 13.87%, 7.70%, 9.71%, and 19.45% in the poorly cohesive, tubular, mucinous, and papillary adenocarcinomas, respectively, according to the WHO classification. The FDG uptake in diffuse type was significantly lower than that in the intestinal type (p = 0.000). The SUVmax and TLR of the CD34(+) group (mean SUVmax, 5.50; TLR, 1.56) were significantly lower than those of the CD34(−) group (mean SUVmax, 14.09; TLR, 4.09). RFS was not associated with TLR or CD34 expression. ConclusionGC, which has abundant tumor stroma characterized by high CD34 expression on IHC, shows low FDG uptake.

Effect of metformin on 18F-fluorodeoxyglucose uptake and positron emission tomographic imaging.

Metformin is widely used to treat diabetes, but induces changes in glucose uptake in both normal organs and tumors. Here, we review the effects of metformin on the uptake of 18F-fludeoxyglucose (18F-FDG) in tissues and tumors, and its influence on 18F-FDG positron emission tomographic imaging (18F-FDG PET), as well as the mechanisms involved. This is an important issue, because metformin has diverse effects on tissue uptake of 18F-FDG, and this can affect the quality and interpretation of PET images. Metformin increases glucose uptake in the gastrointestinal tract, cerebral white matter, and the kidney, while regions of the cerebrum associated with memory show decreased glucose uptake, and the myocardium shows no change. Hepatocellular carcinoma and breast cancer show increased glucose uptake after metformin administration, while thyroid cancer shows decreased uptake, and colon and pancreatic cancers show no change. A high-energy diet increases 18F-FDG uptake, but this effect is blocked by metformin. Withdrawal of metformin 48 h before PET image acquisition is widely recommended. However, based on our review of the literature, we propose that the differentiation of metformin discontinuation could be reasonable. But future clinical trials are still needed to support our viewpoint.

Heightened splenic and bone marrow uptake of 18F-FDG PET/CT is associated with systemic inflammation and subclinical atherosclerosis by CCTA in psoriasis: An observational study

Background and aimsPsoriasis is an immune-mediated inflammatory disease with increased risk of myocardial infarction. Preclinical studies in psoriasis models show an association between chronic inflammation and immune cell proliferation in the spleen and bone marrow (BM). We sought to test the hypothesis that splenic and BM 18F-fluorodeoxyglucose (18F-FDG) uptake is heightened in psoriasis and that higher uptake associates with systemic inflammation and subclinical atherosclerotic disease measures in this cohort. MethodsMultimodality imaging and biomarker assays were performed in 240 participants (210 with psoriasis and 30 healthy). Splenic and BM uptake was obtained using 18F-FDG positron emission tomography/computed tomography (PET/CT). Coronary artery plaque characteristics including non-calcified burden (NCB) and lipid rich necrotic core (LRNC) were quantified using a dedicated software for CT angiography. All analyses were performed with StataIC 16 (Stata Corp., College Station, TX, USA). ResultsSplenic and BM 18F-FDG uptake was increased in psoriasis (vs. healthy volunteers) and significantly associated with proatherogenic lipids, immune cells and systemic inflammation. Higher splenic 18F-FDG uptake associated with higher total coronary burden (β = 0.37; p<0.001), NCB (β = 0.39; p<0.001), and LRNC (β = 0.32; p<0.001) in fully adjusted models. Similar associations were seen for BM 18F-FDG uptake in adjusted models (β = 0.38; β = 0.41; β = 0.24; respectively, all p<0.001). ConclusionsHeightened splenic and BM uptake of 18F-FDG is associated with proatherogenic lipids, immune cells, inflammatory markers and coronary artery disease. These findings provide insights into atherogenic mechanisms in psoriasis and suggest that immune cell proliferation in the spleen and BM is associated with subclinical atherosclerosis.

Elucidating the Etiologies of 18F-fluorodeoxyglucose-Avid Mediastinal Lymph Nodes Among Cancer Patients in a Tuberculosis-Endemic Region Using Endobronchial Ultrasound.

BackgroundNon-malignant conditions, including infections (such as tuberculosis [TB]), can mimic malignancy with regards to their uptake of 18F-fluorodeoxyglucose (18F-FDG) tracer utilized for positron emission tomography-computed tomography (PET-CT) scan, as part of the diagnostic and staging workup of cancer patients. This poses a diagnostic challenge, for which tissue sampling is decisive. In this study, we aimed to determine the underlying etiologies of 18F-FDG-avid mediastinal lymph nodes among cancer patients in a TB-endemic demographic using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and the respective sensitivity and specificity of PET-CT and EBUS in diagnosing malignancy.MethodologyIn this retrospective cross-sectional study, we analyzed the data of all cancer patients with 18F-FDG-avid mediastinal lymphadenopathy on diagnostic PET imaging, who later underwent EBUS-TBNA between July 2013 and December 2018 at our center. Logistic regression analysis was used to determine the relative risk of lymph node characteristics with malignant TBNA cytology, based on which a risk stratification model was formulated.ResultsA total of 178 patients were included in this study, comprising predominantly males (60.7%). The primary malignancy was lung cancer in 33 (18.5%) patients, while 145 (81.5%) had non-lung cancer. A total of 214 18F-FDG lymph nodes were sampled, out of which TBNA revealed malignant cytology in only 44 (20.6%). The final diagnosis was malignancy, TB, and sarcoidosis in 42 (23.6%), 16 (9%), and 12 (6.7%) patients, respectively. Among the remaining, 98 (55%) patients were determined to have only reactive lymphadenopathy, of which 24 (24.5%) had nodal anthracosis, while TBNA was inadequate for the diagnosis in 10 (5.6%) patients. An increased risk of malignancy was associated with the size of lymph node [odds ratio (OR): 1.58 (confidence interval (CI): 1.19, 2.11; p = 0.001], the standard uptake value (SUV) of the lymph node on PET-CT [OR: 1.30 (CI: 1.15, 1.45); p = 0.001], and with primary lung malignancy [OR: 4.44 (CI: 1.96, 10.06); p = 0.001]. At an SUV cut-off value of 6.0, PET-CT had the sensitivity, specificity, positive predictive value, and negative predictive value of 73%, 70%, 49.3%, and 91.8%, respectively, for diagnosing malignancy, while the same for EBUS was estimated to be 93.3%, 100%, 100%, and 97%, respectively.ConclusionsIn addition to TB, benign etiologies including nodal anthracosis and sarcoidosis predominate as causes of 18F-FDG-avid mediastinal lymphadenopathy in cancer patients of a TB-endemic demographic. The predictable risk of malignancy on PET imaging increases with nodal size, SUV, and lung primary malignancy; however, EBUS clearly demonstrates a higher sensitivity.

A successful case of complete surgical resection via left upper and right lower lobectomy for bilateral lung metastases of a perivascular epithelioid cell tumor in the colon: a case report

BackgroundPerivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms with malignant potential. No effective treatment other than surgical resection has been established for lung metastases of PEComas. We describe a patient who underwent complete surgical resection via bilateral lobectomy involving a two-step procedure for lung metastases 8 years after undergoing radical surgery for a colonic PEComa.Case presentationA 53-year-old woman underwent partial colectomy for a PEComa in the transverse colon 8 years ago. She presented with an abnormal chest shadow during a health examination. Chest computed tomography (CT) revealed a solid nodule 2 cm in diameter located centrally in the right lower lobe and a solid nodule 3 cm in diameter located centrally in the left upper lobe. Positron emission tomography revealed 18F-fluorodeoxyglucose uptake in these nodules. These nodules were suspected to be metastatic tumors of the colonic PEComa and were considered for complete surgical resection. Segmentectomy could not be performed because of the anatomical location of the tumors straddling the segments; therefore, bilateral lobectomy was required for complete surgical resection. Therefore, we performed two-step lobectomy safely with the expectation of pulmonary function recovery. Microscopically, the tumors were diagnosed as lung metastases of the PEComa. One year after the last surgery, no recurrence was detected, and the patient’s pulmonary function improved.ConclusionsThis case indicates that even if multiple lung metastases of a PEComa require bilateral lobectomy, complete resection with a two-step surgery may be considered.

Shoulder adhesive capsulitis in cancer patients undergoing positron emission tomography - computed tomography and the association with shoulder pain.

BACKGROUNDAdhesive capsulitis is a relatively common condition that can develop in cancer patients during treatment. Positron emission tomography - computed tomography (PET-CT) is routinely performed as a follow-up study in cancer patients after therapy. Being aware of PET-CT findings to suggest shoulder adhesive capsulitis may help to alert clinicians for the diagnosis of unsuspected shoulder capsulitis.AIMTo assess the association of shoulder adhesive capsulitis with cancer/therapy type and symptoms in cancer patients undergoing PET-CT.METHODSOur prospective study received Institutional Review Board approval. Written informed consent was obtained from all patients, who answered a questionnaire regarding shoulder pain/stiffness at the time of PET-CT study, between March 2015 and April 2019. Patients with advanced glenohumeral arthrosis, metastatic disease or other mass in the shoulder, or shoulder arthroplasty were excluded. Patterns of shoulder capsule 18F-fluorodeoxyglucose (FDG) uptake were noted. Standard Uptake Value (SUV)max and SUVmean values were measured at rotator interval (RI) and deltoid muscle in bilateral shoulders. Normalized SUV (SUV of RI/SUV of deltoid muscle) was also calculated. We assessed if SUV values are different between symptomatic and asymptomatic patients in both shoulders. Covariates were age, gender, and therapy type (surgery, chemotherapy, radiation). Wilcoxon rank sum tests were used to compare unadjusted marginal differences for age, SUV measurements between symptomatic and asymptomatic patients. Multiple linear regression models were used to examine the relationship between right or left shoulder SUV measurements and symptom status, after adjusting for covariates. Statistical significance level was set at P < 0.05.RESULTSOf 252 patients initially enrolled for the study (mean age 66 years, 67 symptomatic), shoulder PET-CT data were obtained in 200 patients (52 were excluded due to exclusion criteria above). The most common cancer types were lymphoma (n = 61), lung (n = 54) and breast (n = 53). No significant difference was noted between symptomatic and asymptomatic patients in terms of age, gender, proportion of patients who had surgical therapy and radiation therapy. A proportion of patients who received chemotherapy was higher in patients who were asymptomatic in the right shoulder compared to those symptomatic in the right shoulder (65% vs 48%, P = 0.012). No such difference was seen for the left shoulder. In both shoulders, SUVmax and SUVmean were higher in symptomatic shoulders than asymptomatic shoulders (Left SUVmax 2.0 vs 1.6, SUVmean 1.6 vs 1.3, both P < 0.002; Right SUVmax 2.2 vs 1.8, SUVmean 1.8 vs 1.5, both P < 0.01). For lung cancer patients, bilateral RI SUVmax and SUVmean values were higher in symptomatic shoulders than asymptomatic shoulders. For other cancer patients, symptomatic patients had higher left RI SUVmax/mean than asymptomatic patients after adjustment.CONCLUSIONIn symptomatic patients metabolic activities in RI were higher than asymptomatic patients. Adhesive capsulitis should be considered in cancer patients with shoulder symptoms and positive FDG uptake in RI.

Normal imaging findings after ascending aorta prosthesis implantation on 18F-Fluorodeoxyglucose Positron Emission Tomography with computed tomography

BackgroundTo diagnose abnormal 18F-Fluorodeoxyglucose (18F-FDG) uptake in suspected endocarditis after aortic root and/or ascending aorta prosthesis (ARAP) implantation, it is important to first establish the normal periprosthetic uptake on positron emission tomography with computed tomography (PET/CT). MethodsPatients with uncomplicated ARAP implantation were prospectively included and underwent 18F-FDG-PET/CT at either 12 (± 2) weeks (group 1) or 52 (± 8) weeks (group 2) after procedure. Uptake on three different locations of the prosthesis (“cranial anastomosis (CA),” “prosthetic heart valve (PHV),” “ascending aorta prosthesis (AAP)”) was scored visually (none/low/intermediate/high) and quantitatively (maximum standardized uptake value (SUVmax) and target-to-background ratio (SUVratio). ResultsIn total, 20 patients (group 1: n = 10, group 2: n = 10) (mean age 64±7 years, 70% male) were included. Both groups had similar visual uptake intensity for all measured areas (CA: mostly low-intermediate (16/20 (80%)), p = .17; PHV: low-intermediate (16/20 (80%)), p = .88; AAP: low-intermediate (19/20 (95%)), p = .48). SUVmax for CA was 5.6 [4.1-6.1] and 3.8 [3.1-5.9] (median [IQR], p = .19), and around PHV 5.0 [4.1-5.7] and 6.3 [4.6-7.1] (p = .11) for groups 1 and 2, respectively. SUVratio for CA was 2.8 [2.3-3.2] and 2.0 [1.7-2.6] (median [IQR], p = .07) and around PHV 2.5 [2.4-2.8] and 2.9 [2.3-3.5] (median [IQR], p = .26) for groups 1 and 2, respectively. ConclusionNo significant differences were observed between PET/CT findings at 3 months and 1 year after ARAP implantation, warranting caution in interpretation of PET/CT in the first year after implantation.

Plasma Levels of Bile Acids Are Related to Cardiometabolic Risk Factors in Young Adults

ContextBile acids (BA) are known for their role in intestinal lipid absorption and can also play a role as signaling molecules to control energy metabolism. Prior evidence suggests that alterations in circulating BA levels and in the pool of circulating BA are linked to an increased risk of obesity and a higher incidence of type 2 diabetes in middle-aged adults.ObjectiveWe aimed to investigate the association between plasma levels of BA with cardiometabolic risk factors in a cohort of well-phenotyped, relatively healthy young adults.MethodsBody composition, brown adipose tissue, serum classical cardiometabolic risk factors, and a set of 8 plasma BA (including glyco-conjugated forms) in 136 young adults (age 22.1 ± 2.2 years, 67% women) were measured.ResultsPlasma levels of chenodeoxycholic acid (CDCA) and glycoursodeoxycholic acid (GUDCA) were higher in men than in women, although these differences disappeared after adjusting for body fat percentage. Furthermore, cholic acid (CA), CDCA, deoxycholic acid (DCA), and glycodeoxycholic acid (GDCA) levels were positively, yet weakly associated, with lean body mass (LBM) levels, while GDCA and glycolithocholic acid (GLCA) levels were negatively associated with 18F-fluorodeoxyglucose uptake by brown adipose tissue. Interestingly, glycocholic acid (GCA), glycochenodeoxycholic acid (GCDCA), and GUDCA were positively associated with glucose and insulin serum levels, HOMA index, low-density lipoprotein cholesterol, tumor necrosis factor alpha, interleukin (IL)-2, and IL-8 levels, but negatively associated with high-density lipoprotein cholesterol, ApoA1, and adiponectin levels, yet these significant correlations partially disappeared after the inclusion of LBM as a confounder.ConclusionOur findings indicate that plasma levels of BA might be sex dependent and are associated with cardiometabolic and inflammatory risk factors in young and relatively healthy adults.

Association Between Changes in Myocardial F-18 Fluorodeoxyglucose Uptake and Cardiac Toxicity or Overall Survival for Inoperable NSCLC Patients Receiving Chemoradiation

<h3>Purpose/Objective(s)</h3> Previous studies have shown that increased cardiac uptake of 18F-fluorodeoxyglucose (FDG) on positron emission tomography (PET) may be an indicator of myocardial injury after radiotherapy. Our study aimed to investigate the predictive value of changes in myocardial ¹⁸F-FDG uptake for cardiotoxicity and overall survival (OS) in patients with inoperable NSCLC receiving definitive chemoradiation. <h3>Materials/Methods</h3> One hundred and fifty unresectable locally advanced NSCLC patients enrolled in a retrospective study who had undergone pre- and post-chemoradiation FDG-PET imaging were evaluated. Our primary endpoint was grade ≥ 3 cardiac toxicity. Patient clinicopathologic factors, dosimetric parameters for the whole heart and cardiac substructures, and myocardial changes within the irradiated fields on 18F-FDG PET were utilized to seek the best predictive model for cardiotoxicity. Competing risk analysis and Cox regressions analysis were performed. <h3>Results</h3> At a median follow-up interval of 35 months, twenty-six patients (17.3%) developed grade ≥ 3 cardiac everts. Twenty-nine patients (19.3%) showed increased myocardial FDG uptake within the irradiated fields associated with the heart dosimetric parameters. The best multivariable model based on the lowest Akaike information criterion for predicting grade ≥ 3 cardiotoxicity included the following covariates: pre-existing cardiac disease, changes in pre- and post-chemoradiation myocardial SUV_mean (∆SUV_mean), and mean heart dose. Subanalysis showed that pre-existing cardiac disease, ∆SUV_mean, and mean left anterior descending dose were significantly associated with grade ≥ 3 acute coronary syndrome/congestive heart failure events. ∆SUV_mean and grade ≥ 3 cardiac toxicity were independent indicators of OS. <h3>Conclusion</h3> ∆SUV_mean was an independent indicator of grade ≥ 3 cardiac toxicity and OS in unresectable locally advanced NSCLC patients receiving definitive chemoradiation. Changes in myocardial uptake of FDG is a promising biomaker for predicting radiation-induced cardiotoxicity.

Clinical Significance of Peritumoral Adipose Tissue PET/CT Imaging Features for Predicting Axillary Lymph Node Metastasis in Patients with Breast Cancer.

We investigated whether textural parameters of peritumoral breast adipose tissue (AT) based on F-18 fluorodeoxyglucose (FDG) PET/CT could predict axillary lymph node metastasis in patients with breast cancer. A total of 326 breast cancer patients with preoperative FDG PET/CT were retrospectively enrolled. PET/CT images were visually assessed and the maximum FDG uptake of axillary lymph nodes (LN SUVmax) was measured. From peritumoral breast AT, 38 textural features of PET imaging were extracted. The diagnostic ability of PET based on visual analysis, LN SUVmax, and textural features of peritumoral breast AT for predicting axillary lymph node metastasis were assessed using the area under the receiver operating characteristic curve (AUC) values. Among the 38 peritumoral breast AT textural features, grey-level co-occurrence matrix (GLCM) entropy showed the highest AUC value (0.830) for predicting axillary lymph node metastasis. The value of GLCM entropy was higher than that of visual analysis (0.739; p < 0.05) and the AUC value was comparable to that of LN SUVmax (0.793; p > 0.05). In the subgroup analysis of patients with negative findings on visual analysis, GLCM entropy still showed a high diagnostic ability (AUC: 0.759) in predicting lymph node metastasis. The findings suggest a potential diagnostic role of PET/CT imaging features of peritumoral breast AT in predicting axillary lymph node metastasis in patients with breast cancer.

Total lesion glycolysis as a predictor of clinical T3-4a laryngeal cancer with laryngectomy or nonlaryngectomy.

The purpose of the present study is to investigate whether the 18F-fluorodeoxyglucose (18F-FDG) uptake parameter is related to survival outcomes for patients with clinical T3–T4a laryngeal cancer with various definitive treatments including total laryngectomy (TL). Parameters of 18F-FDG uptake in the primary tumors of 46 cases which were assessed by positron emission tomography with computed tomography were enrolled in the present observation study. Monovariate or multivariate survival analyses were performed with log-rank test or Cox regression model, with the hazard ratio (HR) and 95% confidence interval (CI), respectively. Cutoff values of the 18F-FDG uptake parameters were determined by the lowest P-value for monovariate overall survival. In the monovariate analysis, both metabolic tumor volume ≥13.1 and total lesion glycolysis (TLG) ≥46.5 were significantly associated with shorter overall survival, and TLG ≥46.5 was also related to a reduction in distant metastasis-free survival. In the multivariate analysis adjusting for clinical T classification (cT4/cT3) and treatment group (TL/non-TL), TLG (≥46.5/<46.5) was associated with both poorer overall (HR: 3.16, 95% CI: 1.10–9.49) and distant metastasis-free (HR: 8.91, 95% CI: 1.93–62.6) survival. In conclusion, TLG is a predictor for survival in laryngeal cancer.

ANTI-INFLAMMATORY EFFECT OF BIOLOGIC THERAPY IN PATIENTS WITH PSORIATIC DISEASE COMPARED WITH TREATMENT WITH NON-BIOLOGIC DMARDS: A PROSPECTIVE COHORT FDG-PET STUDY

<h3>BACKGROUND</h3> Psoriatic arthritis (PsA) and cutaneous psoriasis (PsO) are linked with an increased risk of adverse cardiovascular events. We hypothesized that central vascular inflammation on F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) in the ascending aorta would improve in these patients following therapy with biologic agents compared to PsO patients receiving non-biologic therapy and non-inflammatory control patients. We also postulated that in patients responding to biologics, there would an improvement in coronary microvascular dysfunction as measured by myocardial blood flow reserve (MFR) determined by rubidium-82 (82Rb) PET. <h3>METHODS AND RESULTS</h3> We studied 3 patient cohorts (patients with PsA and/or PsO started on biologic agents, patients with PsO managed on non-biologic therapy, and control patients with non-inflammatory arthritis). The primary outcome of our study was the change in vascular inflammation, estimated as the target-to-background ratio (TBR) by FDG PET in the most diseased segment of the ascending aorta at baseline compared to 6-month follow-up (TBRmax). We also performed 82Rb PET studies at baseline and 6-month follow-up to determine any changes on left ventricular MFR. A total of 34 participants were enrolled in the study (11 PsA and/or PsO patients on biologic agents, 13 patients in PsO group managed on non-biologic therapy, and 10 in the non-inflammatory control group). The majority (64.7%) of participants were men and the median age was 62 years (IQR: 48, 69). A significant drop in the thoracic aorta uptake was observed in the biologic-treated group (thoracic aorta change in TBRmax: -0.46±0.55) when compared to the change in the thoracic aorta FDG uptake of the PsO group treated with non-biologic therapy (thoracic aorta change in TBRmax: 0.23±0.67). Furthermore, the group with imaging evidence of a response to biologic agents (i.e. TBRmax drop > median value of 7%) maintained MFR (3.40±1.23 MFR to 3.5±1.2 MFR over 6 months) when compared to the group with a below median response on TBRmax which had a drop in MFR (2.9±0.8 MFR to 2.2±0.6 over 6 months) (P=0.03). <h3>CONCLUSION</h3> In a cohort of psoriasis patients treated with biologics, the FDG uptake in the thoracic aorta decreased over the study period compared to psoriasis patients treated with non-systemic therapies as well as controls. Additionally, psoriasis patients treated with biologics who demonstrated a significant anti-inflammatory response on FDG PET imaging, maintained their MFR compared to non-responders. This study supports the notion that there is a positive impact of immune therapies on vascular inflammation and microvascular disease in patients with chronic inflammation.

Normal imaging findings after aortic valve implantation on 18F-Fluorodeoxyglucose positron emission tomography with computed tomography

BackgroundTo determine the normal perivalvular 18F-Fluorodeoxyglucose (18F-FDG) uptake on positron emission tomography (PET) with computed tomography (CT) within one year after aortic prosthetic heart valve (PHV) implantation. MethodsPatients with uncomplicated aortic PHV implantation were prospectively included and underwent 18F-FDG PET/CT at either 5 (± 1) weeks (group 1), 12 (± 2) weeks (group 2) or 52 (± 8) weeks (group 3) after implantation. 18F-FDG uptake around the PHV was scored qualitatively (none/low/intermediate/high) and quantitatively by measuring the maximum Standardized Uptake Value (SUVmax) and target to background ratio (SUVratio). ResultsIn total, 37 patients (group 1: n = 12, group 2: n = 12, group 3: n = 13) (mean age 66 ± 8 years) were prospectively included. Perivalvular 18F-FDG uptake was low (8/12 (67%)) and intermediate (4/12 (33%)) in group 1, low (7/12 (58%)) and intermediate (5/12 (42%)) in group 2, and low (8/13 (62%)) and intermediate (5/13 (38%)) in group 3 (P = 0.91). SUVmax was 4.1 ± 0.7, 4.6 ± 0.9 and 3.8 ± 0.7 (mean ± SD, P = 0.08), and SUVratio was 2.0 [1.9 to 2.2], 2.0 [1.8 to 2.6], and 1.9 [1.7 to 2.0] (median [IQR], P = 0.81) for groups 1, 2, and 3, respectively. ConclusionNon-infected aortic PHV have similar low to intermediate perivalvular 18F-FDG uptake with similar SUVmax and SUVratio at 5, 12, and 52 weeks after implantation.

Myocardial viability with chronic total occlusion assessed by hybrid positron emission tomography/magnetic resonance imaging

BackgroundThe present study was performed to compare the relationship of 18F-fluorodeoxyglucose (FDG) uptake and late gadolinium enhancement (LGE) transmurality with the improvement of left ventricular function in patients with coronary chronic total occlusion (CTO) assessed by hybrid FDG positron emission tomography (PET)/magnetic resonance imaging (MRI). MethodsThirty-eight consecutive patients with CTO underwent FDG PET/MRI. Twenty-three patients then underwent percutaneous coronary intervention (PCI), and the final study population comprised 15 patients who underwent both initial and follow-up MRI. The degree of wall motion abnormality in each of the 17 myocardial segments was evaluated based on the extent of wall thickening on cine MRI using a 5-point scale. ResultsAmong all 646 myocardial segments at baseline, FDG uptake significantly decreased as the transmurality of LGE is advanced. Of the 15 patients who underwent PCI, 152 segments showed wall motion abnormalities at baseline. The functional recovery of the wall motion abnormality of the PET-viable/MRI-viable segments was highest, and that of the PET-nonviable/MRI-nonviable segments was lowest. There were no differences in functional recovery between the PET-viable/MRI-nonviable and PET-nonviable/MRI-viable segments. ConclusionSimultaneous assessment of FDG and LGE using a hybrid PET/MRI system can help to predict functional recovery after PCI in patients with CTO.

MA16.07 Prognostic Value of 18F-Fluorodeoxyglucose Uptake of Bone Marrow on PET/CT in Patients with Limited Disease Small Cell Lung Cancer

AİM AND OBJECTİVES: Small cell lung cancer (SCLC) is a lung malignancy from the neuroendocrine cancer family with poor prognosis and metastases at the time of diagnosis. Advanced age, cachexia, low performance status, extensive disease and high lactate dehydrogenase (LDH) values are poor prognostic factors. We investigated whether 18F-fluorodeoxyglucse (FDG) uptake of bone marrow (BM) on positron emission tomography/computed tomography (PET/CT) has implications for predicting clinical outcomes in patients with limited disease small cell lung cancer (SCLC).

Clinical Significance of 18F-fluorodeoxyglucose and Glucose Transporter 1 mRNA in Clear Cell Renal Cell Carcinoma.

18F-fluorodeoxyglucose (FDG) uptake measurement on positron emission tomography/computed tomography (PET/CT) is difficult in renal tumors because of the nearby renal parenchyma and urinary tract, which excrete FDG. We carefully examined the maximum standardized uptake value (SUVmax) on FDG-PET/CT and investigated the relationship between major glucose transporters in the kidney and clear cell renal cell carcinoma (ccRCC) progression. Forty-five patients with ccRCC underwent FDG-PET/CT for staging and nephrectomy. Glucose transporter mRNA expression was examined in the removed kidney. SUVmax was increased in high-stage and high-grade tumors. Glucose transporter 1 (GLUT1) mRNA expression was higher in tumor tissues, in contrast to other glucose transporters. SUVmax was not correlated with GLUT1 mRNA expression. Kaplan-Meier analysis showed reduced overall and recurrence-free survival in the high SUVmax group. Primary ccRCC lesions show a high SUVmax and GLUT1 mRNA over-expression. SUVmax increases with tumor upstaging and upgrading.

Testicular FDG Uptake on PET/CT in Patients with Lymphoma: Correlation with Age

The purpose of this observational study was to investigate whether the standard uptake value (SUV) measurement has practical utility in distinguishing secondary testicular involvement from physiologic uptake in patients with lymphoma. A Radiology Information System (RIS) search was conducted for all PET/CT studies performed from 2010-2016 on adult male patients with a diagnosis of lymphoma. Patients with clinical or pathologic diagnosis of testicular lymphoma were excluded to undergo a separate analysis. PET/CT images of 606 patients with 1087 scans, in which 2045 testes were included in the field of view, were reviewed and measurements were performed for standardized uptake values of both testicles (SUVmax) as well as of the liver (SUVmax and SUVmean). The mean SUVmax of the testicles was 3.75 ± 0.90 (range 1.16-8.38). The mean ratio of testis SUVmax / liver SUVmean (T/L) was 1.78 ± 0.43. Trends in SUVmax and age were significant for a negative correlation by a small magnitude of 0.066 per 10 years (P < 0.001). T/L had similar changes with significant low magnitude decrease with increasing age (0.059 per 10-year increase, P < 0.001). In our separate analysis of 3 patients with clinical or pathology proven testicular lymphoma, the average pathologic SUVmax was 13.47 (range 11.39-15.97). This study has the largest known sample size for quantifying physiologic uptake in the testes. SUV measurements to quantify F-18 Fluorodeoxyglucose (FDG) uptake on PET/CT likely have practical utility in discriminating between physiologic and pathologic uptake of FDG in cases of secondary testicular lymphoma.

Changes of [18F]FDG-PET/CT quantitative parameters in tumor lesions by the Bayesian penalized-likelihood PET reconstruction algorithm and its influencing factors

BackgroundTo compare the changes in quantitative parameters and the size and degree of 18F-fluorodeoxyglucose ([18F]FDG) uptake of malignant tumor lesions between Bayesian penalized-likelihood (BPL) and non-BPL reconstruction algorithms.MethodsPositron emission tomography/computed tomography images of 86 malignant tumor lesions were reconstructed using the algorithms of ordered subset expectation maximization (OSEM), OSEM + time of flight (TOF), OSEM + TOF + point spread function (PSF), and BPL. [18F]FDG parameters of maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and signal-to-background ratio (SBR) of these lesions were measured. Quantitative parameters between the different reconstruction algorithms were compared, and correlations between parameter variation and lesion size or the degree of [18F]FDG uptake were analyzed.ResultsAfter BPL reconstruction, SUVmax, SUVmean, and SBR were significantly increased, MTV was significantly decreased. The difference values of %ΔSUVmax, %ΔSUVmean, %ΔSBR, and the absolute value of %ΔMTV between BPL and OSEM + TOF were 40.00%, 38.50%, 33.60%, and 33.20%, respectively, which were significantly higher than those between BPL and OSEM + TOF + PSF. Similar results were observed in the comparison of OSEM and OSEM + TOF + PSF with BPL. The %ΔSUVmax, %ΔSUVmean, and %ΔSBR were all significantly negatively correlated with the size and degree of [18F]FDG uptake in the lesions, whereas significant positive correlations were observed for %ΔMTV and %ΔTLG.ConclusionThe BPL reconstruction algorithm significantly increased SUVmax, SUVmean, and SBR and decreased MTV of tumor lesions, especially in small or relatively hypometabolic lesions.

Clinical Utility and Limitation of Diagnostic Ability for Different Degrees of Dysplasia of Intraductal Papillary Mucinous Neoplasms of the Pancreas Using 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography.

Simple SummaryElucidating risk factors for different degrees of dysplasia of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas is important in determining strategies for management. In this study, we searched for risk factors for different degrees of dysplasia of IPMNs. Our study indicated that there were no useful factors that significantly differentiated low-grade dysplasia and high-grade dysplasia; however, 18F-fluorodeoxyglucose–positron emission tomography/computed tomography is useful for differentiating between non-invasive and invasive IPMNs. Our results offer critical information that may determine surgical treatment strategies.The diagnostic value of 18F-fluorodeoxyglucose (FDG) uptake in the management of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas remains unclear. This study aimed to assess the role of FDG uptake in the diagnosis of different degrees of dysplasia of IPMNs. We retrospectively analyzed the following three points in 84 patients with IPMNs: (1) risk factors to predict high-grade dysplasia (HGD) and invasive carcinoma (INV); (2) the relationship between FDG uptake and glucose transporter 1 (GLUT-1) expression; and (3) the relationship between FDG uptake and the presence of mural nodules. The histopathological diagnosis was low-grade dysplasia (LGD) in 43 patients, HGD in 16, and INV in 25. The maximum standardized uptake value (SUV-max) was significantly higher in INV than in LGD/HGD (p < 0.0001, p = 0.0136). The sensitivity and specificity to discriminate INV from LGD/HGD were 80.0% and 86.2%, respectively, using the receiver operator characteristic curve, when the optimal cutoff score of SUV-max was set at 4.03. Those values were not different between HGD and LGD. More than half of HGD patients had low GLUT-1 expression. Taken together, FDG-PET/CT is useful in distinguishing between non-invasive and invasive IPMN. Our results offer critical information that may determine surgical treatment strategies.

Nab-paclitaxel plus S-1 with or without PD-1 inhibitor in pancreatic ductal adenocarcinoma with only hepatic metastases: a retrospective cohort study.

The evidence regarding programmed cell death 1 (PD-1) inhibitors on pancreatic ductal adenocarcinoma (PDAC) with metastases remains controversial. This study aimed to assess the efficacy and safety of Nab-paclitaxel plus S1 (NPS) with or without Sintilimab, a PD-1 inhibitor, in patients with PDAC with only hepatic metastases (mPDAC). Untreated mPDAC patients who received NPS with (the combination group) or without Sintilimab (the NPS group) were retrospectively studied. Surgery was considered when the pancreatic tumor became resectable or borderline resectable on radiological examinations, and with complete metabolic response of liver metastases. Between October 2017 and February 2020, 32 patients were in the combination group and 34 patients in the NPS group. Successful salvage resection was achieved in 17 (25.8%) patients after tumor-downstaging (combination 12 vs. NPS 5, P = 0.03). The median overall survival (OS) was 16.8months in the combination group and 10.0months in the NPS group (P = 0.002). Remarkable OS benefit was observed in patients with decline in CA19-9 of ≥ 50% (16.0 vs. 6.5, P = 0.003), reduction in 18F-fluorodeoxyglucose uptake of primary tumor of ≥ 50% (16.5 vs. 10.0, P < 0. 001) and after salvage resection (20.1 vs. 11.0, P < 0. 001). No significant difference in Grade 3 or higher adverse events were seen between the two groups (40.6% vs. 32.4%, P = 0.49). Despite the inherent biases of this retrospective study, the addition of Sintilimab significantly improved salvage resection rates and OS compared with the NPS regimen and had a favorable safety profile in treatment naïve mPDAC patients.