Low SUVmax Research Articles

First Experience Using 18F-Flubrobenguane PET Imaging in Patients with Suspected Pheochromocytoma or Paraganglioma

Pheochromocytomas and paragangliomas are a rare tumor entity originating from adrenomedullary chromaffin cells in the adrenal medulla or in sympathetic, paravertebral ganglia outside the medulla. Small lesions are especially difficult to detect by conventional CT or MRI and even by SPECT with the currently available radiotracers (e.g., metaiodobenzylguanidine [MIBG]). The novel PET radiotracer 18F-flubrobenguane could change the diagnostic paradigm in suspected pheochromocytomas and paragangliomas because of its homology with MIBG and the general advantages of PET imaging. The aim of this retrospective analysis was to evaluate 18F-flubrobenguane in pheochromocytomas and paragangliomas and to investigate the biodistribution in patients. Methods: Twenty-three patients with suspected pheochromocytoma or paraganglioma underwent PET/CT or PET/MRI at 63 ± 24 min after injection of 256 ± 33 MBq of 18F-flubrobenguane. The SUVmean and SUVmax of organs were measured with spheric volumes of interest. Threshold-segmented volumes of interest were used to measure the SUVmean or SUVmax of the tumor lesions. One reader evaluated all cross-sectional imaging datasets (CT or MRI) separately, as well as the PET hybrid datasets, and reported the lesion number and size. The diagnostic certainty for a positive lesion was scored on a 3-point scale. Results: 18F-flubrobenguane showed a reproducible, stable biodistribution, with the highest SUVmax and SUVmean being in the thyroid gland (30.3 ± 2.2 and 22.5 ± 1.6, respectively), pancreas (12.2 ± 0.8 and 9.5 ± 0.7, respectively), and tumor lesions (16.8 ± 1.7 and 10.1 ± 1.1, respectively) and the lowest SUVmax and SUVmean being in muscle (1.1 ± 0.06 and 0.7 ± 0.04, respectively) and the lung (2.5 ± 0.17 and 1.85 ± 0.13, respectively). In a subgroup analysis, a significantly higher average SUVmean was seen for both pheochromocytoma and paraganglioma than for healthy adrenal glands (11.9 ± 2.0 vs. 9.9 ± 1.5 vs. 3.7 ± 0.2, respectively). In total, 47 lesions were detected. The reader reported more and smaller lesions with higher certainty in PET hybrid imaging than in conventional imaging; however, statistical significance was not reached. Of the 23 (23/47, 49%) lesions smaller than 1 cm, 61% (14/23) were found on hybrid imaging only. Conclusion: Our preliminary data suggest 18F-flubrobenguane PET to be a new, effective staging tool for patients with suspected pheochromocytoma or paraganglioma. Major advantages are the fast acquisition and high spatial resolution of PET imaging and the intense uptake in tumor lesions, facilitating detection. Further studies are warranted to define the role of 18F-flubrobenguane PET, particularly in comparison to standard diagnostic procedures such as MRI or 123I-MIBG SPECT/CT.

Comparing prognostic factors of Glut-1 expression and maximum standardized uptake value by FDG-PET in patients with resectable pancreatic cancer

BackgroundThis study aimed to assess the prognostic values of preoperative maximum standardized uptake value (SUVmax) of primary pancreatic tumors and Glut-1 expression in patients with resectable pancreatic ductal adenocarcinoma (R-PDAC), and to investigate whether Glut-1 expression is more effective than SUVmax in predicting survival in patients with R-PDAC. MethodsWe investigated 101 R-PDAC patients who underwent pancreatectomy for pancreatic cancer treatment. SUVmax analyzed through 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT), and Glut-1 expression, were assessed for predicting the prognosis of patients with R-PDAC. ResultsIn patients with R-PDAC, the high SUVmax group (≥4.25) had significantly shorter overall survival (OS) and disease-free survival (DFS) than the low SUVmax group (＜4.25). Surprisingly, Glut-1 expression was not significantly correlated with SUVmax. Moreover, the high Glut-1 expression group, which was related to higher levels of CA 19–9, had significantly shorter OS and DFS than the low Glut-1 expression group. Furthermore, among the high SUVmax group, OS and DFS were significantly shorter in the high Glut-1 expression group. Multivariate analyses revealed that Glut-1 overexpression was an independent prognostic factor in patients with R-PDAC. Glut-1 knockdown also induced cell cycle arrest in PDAC cells in vitro. ConclusionsThe study determined that Glut-1 overexpression is a more powerful prognostic factor than SUVmax for predicting OS and higher risk of recurrence in R-PDAC patients. Glut-1 overexpression is also more likely to be associated with malignant activity in PDAC patients.

Comparison of the prognostic values of 18F-fluorodeoxyglucose parameters from colon and non-colon sites of involvement in diffuse large B-cell lymphoma of the colon

We examined the prognostic values of 18F-fluorodeoxyglucose (18F-FDG) parameters from colon, non-colon, and total lesions in patients with diffuse large B-cell lymphoma (DLBCL) of the colon. Positron emission tomography/computed tomography (PET/CT) in 50 patients was retrospectively analyzed for maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG). During follow-up, 13 patients showed progression and 9 died from disease. Receiver operating characteristics (ROC) curve analysis showed that non-colon and total lesion MTV and TLG and colon lesion SUVmax were associated with progression or death. Significant univariate predictors of poor event-free survival (EFS) included stage III-IV, greater International Prognostic Index (IPI) score, no resection, high non-colon lesion SUVmax, MTV and TLG, and high total lesion MTV and TLG. Univariate predictors of poor overall survival (OS) included stage III–IV, greater IPI score, no resection, high non-colon lesion MTV and TLG, high total lesion MTV, and low colon lesion SUVmax. Multivariate analysis revealed that high non-colon lesion TLG was independently associated with poor EFS and OS. Low colon lesion SUVmax was also independently associated with poor OS. In a subgroup with colon-dominant involvement (n = 35), non-colon lesion MTV and TLG were associated with events and non-colon lesion MTV was associated with patient death. Univariate analysis showed that high non-colon lesion MTV was a significant predictor of poor EFS and OS, while non-colon lesion TLG was a significant predictor of poor OS. Thus, volumetric FDG parameters of non-colon lesions offered significant prognostic information in patients with DLBCL of the colon.

18F-FDG PET/CT SUVmax and serum CEA levels as predictors for EGFR mutation state in Chinese patients with non-small cell lung cancer.

The epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) contribute to an increased response rate, compared with chemotherapy, in patients with inhibitor-sensitive EGFR mutations. The present study evaluated the association between the maximum standardized uptake value (SUVmax) of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT), as well as serum carcinoembryonic antigen (CEA) levels and EGFR mutations prior to treatment, in patients with non-small cell lung cancer (NSCLC). Patients with histologically confirmed NSCLC (n=167), who underwent an 18F-FDG PET/CT scan, EGFR mutation analysis and a serum CEA test participated in the present study. Multivariate logistic regression analysis was used to analyze predictors of EGFR mutations. Receiver-operating characteristic (ROC) curve analysis was performed to determine the efficient cut-off value. Survival rate analysis was evaluated according to SUVmax and EGFR mutation status. A decreased SUVmax and an increased CEA level was observed in patients with EGFR-mutations, compared with patients with wild-type primary lesions and metastatic lymph nodes. The exon 19 EGFR mutation was associated with increased SUVmax, compared with the exon 21 L858R mutation. The ROC analysis indicated that an 18F-FDG PET/CT uptake SUVmax >11.5 may be a predictor of the wild-type EGFR genotype and increased CEA levels (CEA >9.4 ng/ml) were associated with EGFR mutations. Furthermore, patients with no smoking history, low SUVmax of the primary tumor, metastatic lymph nodes and a high CEA level were significantly associated with EGFR mutation status. The results of the present study indicated that patients with advanced NSCLC, particularly Chinese patients, with decreased SUVmax and increased CEA levels are associated with EGFR mutations, which may serve as predictors for the EGFR-TKI therapeutic response.

68Ga-PSMA PET/CT tumour intensity pre-operatively predicts adverse pathological outcomes and progression-free survival in localised prostate cancer.

Prostate-specific membrane antigen (PSMA) positron emission tomography (PSMA-PET) improves prostate cancer staging. Intraprostatic PSMA intensity may predict clinically relevant oncological outcomes. The aim of this study was to investigate the relationship between intraprostatic PSMA intensity and adverse pathology outcomes, including biochemical progression-free survival (PFS) after radical prostatectomy. This is a cohort study of 71 patients with MRI-guided, biopsy-proven prostate cancer and pre-operative 68Ga-PSMA-11 PET/CT prior to radical prostatectomy (RP). Intraprostatic PSMA intensity was correlated to adverse pathology outcomes (Gleason score and upgrading from biopsy, pathological stage) and PFS using multivariate statistical analysis. 68Ga-PSMA-11 PET/CT intensity in vivo predicted all of Gleason score on RP, upgrading from biopsy to RP histopathology, pathological stage, positive surgical margins and PFS. 74.6% (53/71) of patients were free from progression at a median follow-up of 19.5months (0.4-48months). Predictive accuracy was particularly enhanced by PSMA among patients with biopsy Gleason score ≤ 3 + 4 (n = 39) as the most significant predictor of PFS according to Cox-proportional hazards regression. Cox-regression adjusted survival analysis predicted a 5.48-fold increase in hazard for Gleason score ≤ 3 + 4 patients with high (SUVmax > 8) compared with low (SUVmax < 8) PSMA intensity. Intraprostatic 68Ga-PSMA-11 intensity is prognostic and may be a valuable new biomarker in localised prostate cancer, especially in men with biopsy-proven Gleason 3 + 4 disease considering an initial approach of active surveillance or focal therapy.

Prognostic value of O-(2-[18F]-fluoroethyl)-L-tyrosine PET in relapsing oligodendroglioma

Purpose To assess the relationship between F-18-fluoro-ethyl-tyrosine positron emission tomography (FET-PET) parameters of relapsing oligodendroglioma and progression-free survival. Material and methods The relationship of clinical parameters, FET-PET parameters (SUVmax, TBRmax, BTV, time-activity curves) and progression-free survival was analyzed using univariate and multivariate analysis in 42 adult patients with relapsing oligodendroglioma. Kaplan–Meier analysis was used to assess survival. Results Patients who did not undergo surgical resection of their relapsing tumor had significantly lower PFS if the tumor exhibited an SUVmax above 3.40 than those with an SUVmax below 3.40 (13.1 ± 2.3 months vs. 47.3 ± 6.0 months, respectively, p < .001). Patients who underwent surgery had similar PFS as the aforementioned non-operated patients with low SUVmax (53.6 ± 6.7 months, p = .948). The same was true for TBRmax using a threshold of 3.03 (PFS 12.5 ± 2.4 months vs. 44.0 ± 6.3 months / 53.6 ± 6.7 months, respectively; p < .001 / p = .825). Also, subjects with BTV below 10 cm3 that did not undergo surgery had a similar PFS as subjects who underwent surgery (40.2 ± 6.0 months vs. 52.4 ± 8.9 months, respectively, p = .587). Subjects with BTV above 10 cm3 and without surgery had a significantly worse PFS (13.8 ± 3.3 months, p < .001). Multivariate analysis showed that the prognostication by clinical parameters is improved by adding TBRmax to the model (AUC 0.945 (95% CI: 0.881–1.000), true classification rate 88.1%). Conclusion FET-PET may provide added value for the prognostication of relapsing oligodendroglioma in addition to clinical parameters.

Prognostic Implications of 18-FDG Positron Emission Tomography/Computed Tomography in Resectable Pancreatic Cancer.

There are currently no known preoperative factors for determining the prognosis in pancreatic cancer. The aim of this study was to examine the role of 18-fluorodeoxyglucose (18-FDG) positron emission tomography/computed tomography (18-FDG-PET/CT) as a prognostic factor for patients with resectable pancreatic cancer. Data were obtained from a retrospective analysis of patients who had a preoperative PET scan and then underwent pancreatic resection from January 2007 to December 2015. The maximum standardized uptake value (SUVmax) of 18-FDG-PET/CT was calculated. Patients were divided into high (>3.65) and low (≤3.65) SUVmax groups, and compared in terms of their TNM classification (Union for International Cancer Contro classification), pathological grade, surgical treatment, state of resection margins, lymph node involvement, age, sex, diabetes and serum Carbohydrate Antigen 19-9 (CA 19-9) levels. The study involved 144 patients, 82 with high SUVmax pancreatic cancer and 62 with low SUVmax disease. The two groups’ disease-free and overall survival rates were significantly influenced by tumor stage, lymph node involvement, pathological grade, resection margins and SUVmax. Patients with an SUVmax ≤ 3.65 had a significantly better survival than those with SUVmax > 3.65 (p < 0.001). The same variables were independent predictors of survival on multivariate analysis. The SUVmax calculated with 18-FDG-PET/CT is an important prognostic factor for patients with pancreatic cancer, and may be useful in decisions concerning patients’ therapeutic management.

Abdominal extranodal lymphoma detection: positron emission tomography/computed tomography can help

BackgroundLymphoid neoplasms that present with masses are broadly referred to as lymphomas, and they can be classified to two main groups: Hodgkin’s (HL) and non-Hodgkin’s lymphoma (NHL); they are mainly characterized by enlargement of lymph nodes (nodal disease) although any organ in the body can be involved in different settings of the disease (extranodal disease). Adequate staging, which has a direct impact on prognosis, is essential to properly plan therapy. Stage IV disease with extranodal dissemination should be treated by long-term systemic chemotherapy.By adding the metabolic changes to the conventional CT morphologic changes, combined positron emission tomography (PET) and computed tomography (CT) may offer clinically useful addition in staging of lymphomas and detection of extranodal lesions.ResultsThe study included thirty nine patients, with forty-eight extranodal sites with lymphomatous infiltration, twenty-four males (61.5%), and fifteen females (38.4%). The patients showed forty-eight extranodal abdominal lymphomatous infiltration.The study included twelve gastric lymphomatous lesions (25%), twelve splenic lymphomatous lesion (25%), three ileo-caecal lymphomatous lesions (6.25%), three patients (6.25%) with skin infiltration, three adrenal lymphomatous lesions (6.25%), three patients with hepatic lymphoma, and twelve bone marrow infiltrations (25%).The most accurate SUV max cutoff value among studied cases was 3.5, the highest SUV max value noted was 21 in gastric lesions, and the lowest SUV max noted was 4.1 in adrenal lesions.Confirmation of PET/CT results was done by histopathological assessment and post-management follow-up.ConclusionPET/CT study is an effective tool for evaluation of extranodal lymphomas. PET/CT fusion images can affect the clinical management plan by detection of extranodal lymphomas with lymphoma staging modification.

Relationship between the expression of oestrogen receptor and progesterone receptor and 18F-FDG uptake in endometrial cancer.

Background: Progestogens have been widely used for the treatment of inoperable endometrial cancer or younger patients with endometrial cancer. Identifying markers that are predictive of a response to progestogens is critical for successful therapy. Molecular imaging with 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) can provide metabolic phenotypic information of many malignancies. We investigated whether estrogen receptor (ER)/progestogen receptor (PR) status is correlated with 18F-FDG uptake, and whether 18F-FDG PET/CT could be useful for predicting ER/PR status in endometrial cancer.Results: Endometrial cancers in the ER-positive group had lower SUVmax than those in the ER-negative group (12.3 ± 6.2 vs. 19.9 ± 6.6, respectively; P = 0.003). Endometrial cancers in the PR-positive group also had lower SUVmax than those in the PR-negative group (12.4 ± 6.2 vs. 20.0 ± 6.9, respectively; P = 0.005). Multivariate analysis indicated that SUVmax and tumour differentiation grade were significantly associated with both ER and PR status (P = 0.027 and P = 0.044, respectively). ER expression was predicted with an accuracy of 74.2% when a SUVmax value of 15.3 was used as a cutoff point for analysis. Similarly, PR expression was predicted with an accuracy of 74.2%, when a SUVmax value of 15.95 was used as the threshold for analysis.Conclusion: Higher 18F-FDG accumulation in endometrial cancers is correlated with negative ER/PR expression. 18F-FDG PET/CT may be used to predict the status of ER/PR and thus aid in optimal treatment decision in endometrial cancers.Methods: We carried out a retrospective analysis on 62 endometrial cancer patients who underwent 18F-FDG PET/CT before radical treatment. The maximum of standardized uptake value (SUVmax) was calculated from the 18F-FDG accumulation of the primary tumor. The relationship between SUVmax and ER/PR status was analyzed.

Diagnostic and Predictive Values of 18F-FDG PET/CT Metabolic Parameters in EGFR-Mutated Advanced Lung Adenocarcinoma.

PurposeThe clinical implications of the metabolic parameters of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) in epidermal growth factor receptor (EGFR)-mutated lung cancer are not fully understood. The aim of this study was to evaluate the diagnostic and prognostic utility of the parameters in EGFR-mutated lung cancer patients.Patients and MethodsWe retrospectively enrolled 134 patients with advanced lung adenocarcinoma (72 EGFR-negative and 62 EGFR-positive). We evaluated the correlation between EGFR mutational status and the maximum standardized uptake value (SUVmax), as well as the associations between treatment outcomes in EGFR-mutated patients and various metabolic parameters of primary tumors. For the best predictive parameters, we calculated the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) using two SUV cutoffs: 1.5 (MTV1.5, TLG1.5) and 2.5 (MTV2.5, TLG2.5).ResultsMean SUVmax was lower for EGFR-mutated tumors compared with EGFR wild-type (6.11 vs 10.41, p < 0.001) tumors. Low SUVmax was significantly associated with positive EGFR mutation (odds ratio = 1.74). Multivariate analysis for survival demonstrated that high MTV1.5, TLG1.5, MTV2.5, and TLG2.5 were independently associated with shorter progression-free survival (PFS) and overall survival (OS), and the highest hazard ratios were found in TLG1.5 (3.26 for PFS and 4.62 for OS).ConclusionSUVmax may be predictive for EGFR mutational status, and MTV and TLG of primary tumors may be promising prognostic parameters; 18F-FDG PET/CT has potential utility for the risk stratification of EGFR-mutated patients treated with targeted therapy.

Total Lesion Glycolysis Ratio in Positron Emission Tomography/Computed Tomography Images During Neoadjuvant Chemotherapy Can Predict Pathological Tumor Regression Grade and Prognosis in Patients with Locally Advanced Squamous Cell Carcinoma of the Esophagus.

The usefulness of quantitating tumor lesion glycolysis (TLG) from 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) findings as a tool for determining the effect of neoadjuvant chemotherapy (NAC) in esophageal squamous cell carcinoma (ESCC) has not yet been established. The cohort of this retrospective study comprised 46 patients who had undergone NAC and subsequent esophagectomy for locally advanced ESCC between January 2008 and December 2017. PET/CT was conducted before and after NAC to assess its therapeutic effect. Associations between changes in TLG values during NAC and clinicopathological findings, pathological tumor regression grade (TRG), and prognosis were assessed. Most patients received two courses of DCF (Docetaxel, Cisplatin, and Fluorouracil) as NAC. The mean TLG value of the primary tumor decreased significantly after NAC. The median follow-up period was 41months. The Kaplan-Meier method, analyzed by log-rank test, showed that low TLG ratio (≤ 0.4) and low SUVmax ratio (≤ 0.6) were associated with favorable survival outcomes (P = 0.0073 and P = 0.032, respectively). Univariate and multivariate analysis revealed that TLG ratio and achievement of pathological cure were independent prognostic factors for overall survival. TLG ratio was also associated with pathological TRG (TRG 0-1a vs 1b-3) (P = 0.0016). TLG ratio before and after NAC is clinically useful in predicting both histological response and survival outcome after NAC and subsequent esophagectomy in patients with ESCC.

Relationship of EGFR Mutation to Glucose Metabolic Activity and Asphericity of Metabolic Tumor Volume in Lung Adenocarcinoma.

EGFR-mutation (EGFR-mt) is a major oncogenic driver mutation in lung adenocarcinoma (ADC) and is more often observed in Asian population. In lung ADC, some radiomics parameters of FDG PET have been reported to be associated with EGFR-mt. Here, the associations between EGFR-mt and PET parameters, particularly asphericity (ASP), were evaluated in Asian population. Lung ADC patients who underwent curative surgical resection as the first treatment were retrospectively enrolled. EGFR mutation was defined as exon 19 deletion and exon 21 point mutation and was evaluated using surgical specimens. On FDG PET, image parameters of maximal standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and ASP were obtained. The parameters were compared between EGFR-mt and wild type (EGFR-wt) groups, and the relationships between these PET parameters and EGFR-mt were evaluated. A total of 64 patients (median age 66years, M:F = 34:30) were included in the analysis, and 29 (45%) patients showed EGFR-mt. In EGFR-mt group, all the image parameters of SUVmax, MTV, TLG, and ASP were significantly lower than in EGFR-wt group (all adjusted P < 0.050). In univariable logistic regression, SUVmax (P = 0.003) and ASP (P = 0.010) were significant determinants for EGFR-mt, whereas MTV was not (P = 0.690). Multivariate analysis revealed that SUVmax and ASP are independent determinants for EGFR-mt, regardless of inclusion of MTV in the analysis (P < 0.05). In Asian NSCLC/ADC patients, SUVmax, MTV, and ASP on FDG PET are significantly related to EGFR mutation status. Particularly, low SUVmax and ASP are independent determinants for EGFR-mt.

Low metabolic activity in primary gastric adenocarcinoma is associated with resistance to chemoradiation and the presence of signet ring cells.

Preoperative chemoradiation is a potential treatment option for localized gastric adenocarcinoma (GAC). Currently, the response to chemoradiation cannot be predicted. We analyzed the pretreatment maximum standardized uptake value (SUVmax) and total lesion glycolysis (TLG) on positron emission tomography/computed tomography as potential predictors of the response to chemoradiation. We analyzed the SUVmax and TLG data from 59 GAC patients who received preoperative chemoradiation. We used logistic regression models to predict a pathologic complete response (pCR) and Kaplan-Meier curves to determine overall survival among patients with high and low SUVmax or TLG. Twenty-nine patients (49%) had Siewert type III adenocarcinoma and 30 (51%) had tumors located in the lower stomach. Forty-one patients had poorly differentiated GAC, and 26 had signet ring cells. The median SUVmax was 7.3 (0-28.2) and the median TLG was 56.6 (0-1881.5). Patients with signet ring cells had a low pCR rate, as well as a low SUVmax and TLG. In the multivariable logistic regression model, high SUVmax was a predictor of pCR (odds ratio = 11.1, 95% confidence interval = 2.12-50.0, p = 0.004). Overall survival was not associated with the SUVmax (log-rank p = 0.69) or TLG (log-rank p = 0.85) CONCLUSION: A high SUVmax was associated with sensitivity to chemoradiation and pCR in GAC, and signet ring cells seemed to confer resistance.

Comparative evaluation of 68Ga-labelled TATEs: the impact of chelators on imaging

Background68Ga-labelled peptides targeting somatostatin receptor 2 (SSTR2) have demonstrated encouraging results in managing patients with neuroendocrine tumours (NETs). In addition to metal chelation, bifunctional chelators have also been found to impact imaging outcomes due to their differences in stability, charge, hydrophilicity, etc. In the present work, a comparative pharmacokinetic evaluation and imaging characteristics were performed between 68Ga-labelled somatostatin analogues (TATE) using NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid) and DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) as bifunctional chelating agents (BFCAs).ResultsBoth 68Ga-NOTA-TATE and 68Ga-DOTA-TATE were obtained with high radiochemical purity. 68Ga-NOTA-TATE demonstrated higher in vitro stability (≥ 99%) than 68Ga-DOTA-TATE (≥ 95%) after 3 h of incubation. The water solubilities (partition coefficients, − 1.76 ± 0.06 vs. − 2.72 ± 0.16) and plasma protein binding rates (12.12% vs. 30.6%) were lower for 68Ga-NOTA-TATE than for 68Ga-DOTA-TATE. Differential pharmacokinetics and comparable tumour affinities (within 1 h) were observed in AR42J tumour-bearing mice. Healthy volunteer imaging studies showed comparable distribution patterns of these two imaging agents. However, the maximum standardized uptake values (SUVmax) of the two tracers varied in each organ. The two PET agents demonstrated almost identical SUVmax values in the kidneys. 68Ga-NOTA-TATE did have a lower SUVmax in most other organs compared with 68Ga-DOTA-TATE, including the liver (4.2 vs. 10.1), potentially due to the lower protein binding rate.Conclusion68Ga-NOTA-TATE and 68Ga-DOTA-TATE demonstrated comparable tumour uptake in an AR42J mouse model. An initial clinical study revealed that 68Ga-NOTA-TATE may have reduced background uptake in the major organs such as the liver. Although the subject numbers were limited, further investigation of 68Ga-NOTA-TATE is warranted for detecting SSTR2-positive neuroendocrine tumours.

Prognostic Values of Baseline 18F-FDG PET/CT in Patients with Peripheral T-Cell Lymphoma.

Purpose In the present study, we aimed to investigate whether the metabolic parameters on baseline 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) could be used to predict prognosis in peripheral T-cell lymphomas (PTCL). Methods A total of 51 nodal PTCL patients who underwent baseline 18F-FDG PET/CT were retrospectively evaluated in the present study. Total metabolic tumor volume (TMTV), total lesion glycolysis (TLG), and maximum standardized uptake value (SUVmax) were also assessed. Besides, the National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) was also included. Log-rank test and Cox regression analysis were used to evaluate progression-free survival (PFS) and overall survival (OS). Results The median follow-up was 18 months. Patients with low TLG, TMTV, and SUVmax levels had a significantly better clinical outcome than those with high TLG, TMTV, and SUVmax levels. The 2-year PFS rates of the high- and low-TMTV groups were 34.62% and 80%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (p < 0.001), whereas the corresponding 2-year OS rates were 46.15% and 84.00%, respectively (n = 10), intermediate-risk group with TMTV > 62.405 or NCCN-IPI score of 4-8 (2-year PFS and OS were 52.4% and 66.7%, respectively, n = 10), intermediate-risk group with TMTV > 62.405 or NCCN-IPI score of 4-8 (2-year PFS and OS were 52.4% and 66.7%, respectively, n = 10), intermediate-risk group with TMTV > 62.405 or NCCN-IPI score of 4-8 (2-year PFS and OS were 52.4% and 66.7%, respectively, Conclusions Baseline TMTV and TLG were independent predictors of PFS and OS in PTCL patients, and SUVmax and NCCN-IPI scores were also independent predictors of OS. Moreover, the combination of TMTV and NCCN-IPI scores improved patient risk-stratification at the initial stage and might contribute to the adjustment of the therapeutic regime. This trial is registered with ChiCTR1900025526.

Diffuse large B-cell lymphoma with low 18F-fluorodeoxyglucose avidity features silent B-cell receptor signaling

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of aggressive lymphomas exhibiting increased glucose uptake. However, some DLBCLs featuring relatively low 18F-fluorodeoxyglucose (18F-FDG) uptake denoted by the maximum standardized uptake value (SUVmax) on PET/CT have been identified. The biologic correlates of such a heterogeneity have remained largely unknown. Herein, we immunohistochemically detected and found low FDG-avid DLBCL cases featuring lower expression of some key molecules involved in B-cell receptor (BCR) signaling (pSYK) and glucose metabolism (GLUT1 and HK2). Besides, BCR-deficient DLBCL xenografts were found displaying lower SUVmax and expressions of pSYK, GLUT1, and HK2. Further immunoblotting demonstrated expressions of GLUT1 and HK2 in BCR-dependent DLBCLs could be down-regulated by a chemical SYK inhibition, whereas the inhibitory effects were not observed in BCR-deficient tumors. These findings suggest low FDG-avid DLBCLs display a silent BCR signaling and PET/CT might be utilized to tailor the BCR signaling-inhibitory treatment.

FDG and PSMA PET in metastatic castration-resistant prostate cancer (mCRPC).

23 Background: We hypothesized 18F-DCFPyL (PSMA-based tracer) and/ or 18F-FDG (glucose metabolism-based tracer) PET/CT might provide different/complementary molecular imaging information in men with mCRPC treated with abiraterone (A) or enzalutamide (E). Methods: In this prospective cohort study (MISTER trial) mCRPC patients (pts) had conventional imaging and both PSMA and FDG PET/CT prior to standard treatment with A or E, repeated after ~10 weeks on treatment. The main objective was to compare changes in PET/CT findings with conventional imaging. Median of PET maximum standardized uptake value (SUVmax) was measured across all PET avid disease sites and change in SUVmax was evaluated in the 5 hottest sites per patient. Review of PET/CT was performed by 3 experts based on consensus. Results: 36 men were enrolled between 2/2017-12/2018, of whom 28 had treatment and followup imaging. To date, 13 cases have been reviewed: mean age 71.2 years, 7 (53.9%) were ECOG=0, median duration since diagnosis of initial cancer 7.5 months and 8 (61.5%) were stage II/III. PSMA detected more skeletal metastases, positive nodes and non-skeletal, non-nodal metastases in 5/5/3 (39%/39%/23%) men, while FDG detected more non-skeletal, non-nodal metastases in 1 man. Following treatment, new lesions were seen in 3 men on both PSMA and FDG, 3 with PSMA only, and 1 with FDG only. 12 men had baseline FDG-avid disease with median SUVmax 6.5 pre-treatment and 3.8 following therapy (all men had lower SUVmax post-treatment). All 13 men had PSMA-avid disease with median SUVmax 17.6 at baseline and 18.7 post-therapy. Following treatment, 8/12 men (67%) had SUV declines ≥30% (2 had new lesions), 4 had declines of 0-30% (2 had new lesions) using FDG; at followup, 1/13 men had PSMA SUVmax declines ≥30% or more, 6 had declines of 0-30% (2 had new lesions), 5 had SUV increases of 0-30% (4 had new lesions) and 1 had &gt;30% increase. Conclusions: In early analyses, PSMA identified more disease burden in mCRPC pts and was more avid than FDG. SUVmax for FDG declined following treatment in all men, while PSMA changes were heterogeneous. Potential prognostic value of early PSMA and FDG imaging changes on clinical outcomes will be correlated with conventional imaging along with review of remaining cases. Clinical trial information: NCT02813226.

Prognostic value of [18F]FDG PET/CT parameters in surgically resected primary lung adenocarcinoma: a single-center experience.

To evaluate the prognostic role of maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) measured by FDG-positron emission tomography (PET)/computed tomography (CT) in patients with primary lung adenocarcinoma undergoing surgical resection. All consecutive patients undergoing curative surgery for primary lung adenocarcinoma at the Thoracic Surgery Unit of the University Hospital of Parma between January 2009 and December 2014 were retrospectively analyzed. The cutoff point of each continuous PET parameter was determined through receiver operating characteristic curve and Youden index, using overall survival (OS) as the classification status. Univariate and multivariate Cox proportional hazards models were applied to evaluate the association between OS and potential prognostic variables, including SUVmax, MTV, and TLG. A total of 193 patients were considered eligible for this study. The mean 5-year OS rate was 70.5 ± 3.5%. Acinar and lepidic patterns were more frequently associated with absent or low (<2.5) SUVmax values [18F]FDG uptake. At univariate analysis, male sex, advanced stage, micropapillary and solid pattern, lymphatic, blood vessels and pleural invasion, high SUVmax, MTV, and TLG were significantly associated with poorer OS. Multivariate analyses revealed that only sex, stage, and TLG were independent factors for OS, with male sex, stage 3+4, and high TLG value (p = 0.041) significantly associated with poorer OS. In this study, [18F]FDG PET/CT parameters SUVmax, MTV, and TLG were prognostic factors in patients with surgically resected lung adenocarcinoma, able to predict OS and helping to further stratify these patients into prognostic subsets. Elevated TLG was also an independent predictor for shorter OS.

Prognostic value of 18FDG PET/CT volumetric parameters in the survival prediction of patients with pancreatic cancer

PurposeTo investigate the value of 18 FDG PET/CT volumetric parameters in the prediction of overall survival (OS) in patients with pancreatic cancer and also, assess their independence relative to well-established clinico-pathological variables. MethodsWe conducted a retrospective analysis of patients with a confirmed diagnosis of pancreatic cancer who underwent 18 FDG PET/CT. The tumour maximum standardised uptake value (SUVmax) in addition to SUVmean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated. The prognostic value of 18 FDG PET/CT and clinico-pathological parameters for OS were assessed using univariate and multivariable analyses. ResultsA sum of 89 patients were analysed in this study. Median survival for patients categorised as having high TLG (≥55) and low TLG (<55) was 18 vs 5 months (p < 0.001). Similarly, the respective high vs low SUVmean, MTV and SUVmax were 18 vs 6 months (p = 0.001), 16 vs 6 months (p = 0.002) and 18 vs 6 months (p = 0.001). Univariate analysis showed SUVmax, SUVmean, MTV, TLG, tumour size, tumour differentiation and presence of distant metastasis as prognostic factors for OS. On multivariable analysis, TLG (HR 2.0, 95% CI 1.26–3.18, p = 0.004) and the presence of distant metastasis (HR 3.37, 95% CI 1.97–5.77, p < 0.001) emerged as independent prognostic factors. Subgroup analysis identified TLG as the only significant PET metric after adjusting for the presence of distant metastasis. Conclusions18 FDG PET/CT is a useful tool in the preoperative evaluation of patients with pancreatic cancer. Tumour TLG offer an independent prognostic value in both potentially operable and metastatic disease settings.

Feasibility Study and Preliminary Results of Prognostic Value of Bone SPECT-CT Quantitative Indices for the Response Assessment of Bone Metastatic Prostate Carcinoma to Abiraterone.

Objective: We assessed the prognostic value of quantitative indices extracted from bone SPECT-CT to evaluate the response of bone metastatic castrate-resistant prostate cancer (BmCRPC) to abiraterone.Methods: Consecutive patients with BmCRPC initiating treatment with abiraterone from March 2014 to March 2015 were prospectively included. Three 2-bed SPECT-CT [at baseline [M0], after 3 months [M3], and 6 months [M6] of treatment], were planned (Symbia Intevo®, Siemens). SPECT data were reconstructed using an Ordered Subset Conjugate Gradient Minimization (OSCGM) algorithm allowing SUV quantification. SUVmax and SUVpeak of the highest uptake lesion were measured in each SPECT-CT. Total Neoplastic Osteoblastic Metabolic Volume (NOMV) was assessed. PSA level was recorded at baseline, M3, and M6 of treatment. Overall survival (OS), progression-free survival (PFS), and disease-specific survival (DSS) were calculated.Results: Nineteen patients aged 71.1 ± 7.7 years were included. Low M0 SUVmax was significantly predictive of longer OS (p = 0.04). Low NOMV at M0 were significantly predictive of longer PFS (p = 0.02). Patients with increase of at least 12.5% of the SUVpeak of the highest uptake lesion between M0 and M3 (ΔSUVpeakM0M3) had a significantly longer OS (p = 0.03). Patients with increase (or decrease lesser than 25%) of ΔSUVpeakM0M3 had a significantly longer DSS (p = 0.01). Patients with increase of NOMV of at least 45% between M0 and M6 had a significantly shorter PFS (p < 0.001). Variations of NOMV between M0 and M6 were significantly correlated with PSA variations between M0 and M6 (rs = 0.73, p = 0.02).Conclusions: Quantitative bone SPECT-CT appears to be a promising tool of BmCRPC assessment. Early flare-up phenomenon seems to predict longer OS.