Value Of Positron Emission Tomography Research Articles

Value of integrated PET-IVIM MRI in predicting lymphovascular space invasion in cervical cancer without lymphatic metastasis

To evaluate the contributory value of positron emission tomography (PET)-intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) in the prediction of lymphovascular space invasion (LVSI) in patients with cervical cancer without lymphatic metastasis. A total of 90 patients with cervical cancer without signs of lymph node metastasis on PET/MRI were enrolled in this study. The tumours were classified into LVSI-positive (n = 25) and LVSI-negative (n = 65) groups according to postoperative pathology. The PET-derived parameters (SUVmax, SUVmean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG)) and IVIM-derived parameters (ADCmean, ADCmin, Dmean, Dmin, f, D* and gross tumour volume (GTV)) between the two groups were evaluated using a Student's t test (Mann-Whitney U test for variables with a nonnormal distribution) and receiver operating characteristic (ROC) curves. The optimal combination of PET/MR parameters for predicting LVSI was investigated using univariate and multivariate logistic regression models and evaluated by ROC curves. The optimal cutoff threshold values corresponded to the maximal values of the Youden index. A control model was established using 1000 bootstrapped samples, for which the performance was validated using calibration curves and ROC curves. PET-derived parameters (SUVmax, SUVmean, MTV, TLG) and IVIMMRI-derived parameters (Dmin, ADCmin, GTV) were significantly different between patients with and without LVSI (P < 0.05). Logistic analyses showed that a combination of TLG and Dmin had the strongest predictive value for LVSI diagnosis (area under the curve (AUC), 0.861; sensitivity, 80.00; specificity, 86.15; P < 0.001). The optimal cutoff threshold values for Dmin and TLG were 0.58 × 10-3 mm2/s and 66.68 g/cm3, respectively. The verification model showed the combination of TLG and Dmin had the strongest predictive value, and its ROC curve and calibration curve showed good accuracy (AUC, 0.878) and consistency. The combination of TLG and Dmin may be the best indicator for predicting LVSI in cervical cancer without lymphatic metastasis.

The value of 18F-FDG-PET-CT in the management of infective native aortic aneurysms.

The objective of this systematic literature review was to explore the value of positron emission tomography combined with low-dose computed tomography (18F-FDG-PET-CT) in the diagnostics of infective native aortic aneurysm (INAA). A systematic literature review was performed using the search terms mycotic- and infected aortic aneurysms in Medline and Sciencedirect databases, published between 1 January 2000 and 1 January 2020. Using the PRISMA statement, articles were scrutinized according to a predefined protocol including: timing of 18F-FDG-PET-CT examination, the maximum standardized uptake value (SUVmax), additional findings on examination, and findings on repeated scanning of 18F-FDG-PET-CT. Four studies were included in the analysis, comprising a total of 11 patients. Two studies were single case reports, and two were small case series, all were graded to be of low quality with high risk of bias. All patients were examined with a preoperative 18F-FDG-PET-CT, and 10 (91%) had increased 18F-FDG uptakes. The median SUVmax value was 6.53, range 4.46-9.23. The mean duration of antibiotic therapy prior to 18F-FDG-PET-CT was not known. Two patients were examined with repeated 18F-FDG-PET-CT examinations after treatment, where a decrease in SUVmax values could be demonstrated after successful treatment. The literature on 18F-FDF-PET/CT for diagnosing infective native aortic aneurysms is scarce. However, there might be a role for 18F-FDF-PET/CT in the management of the disease, in particular for patients with clinical suspicion of INAA without convincing findings on CT. SUVmax values ranging from 4.5 to 6.5 could be guiding and suggestive of metabolic activity in agreement of INAA. However, further conclusions on its usefulness, robustness and specific SUVmax values are premature, and a definitive cut-off value is probably not attainable.

Resting-State Functional Connectivity Disruption as a Pathological Biomarker in Autosomal Dominant Alzheimer Disease.

Aim: Identify a global resting-state functional connectivity (gFC) signature in mutation carriers (MC) from the Dominantly Inherited Alzheimer Network (DIAN). Assess the gFC with regard to amyloid (A), tau (T), and neurodegeneration (N) biomarkers, and estimated years to symptom onset (EYO). Introduction: Cross-sectional measures were assessed in MC (n = 171) and mutation noncarrier (NC) (n = 70) participants. A functional connectivity (FC) matrix that encompassed multiple resting-state networks was computed for each participant. Methods: A global FC was compiled as a single index indicating FC strength. The gFC signature was modeled as a nonlinear function of EYO. The gFC was linearly associated with other biomarkers used for assessing the AT(N) framework, including cerebrospinal fluid (CSF), positron emission tomography (PET) molecular biomarkers, and structural magnetic resonance imaging. Results: The gFC was reduced in MC compared with NC participants. When MC participants were differentiated by clinical dementia rating (CDR), the gFC was significantly decreased in MC CDR >0 (demented) compared with either MC CDR 0 (cognitively normal) or NC participants. The gFC varied nonlinearly with EYO and initially decreased at EYO = -24 years, followed by a stable period followed by a further decline near EYO = 0 years. Irrespective of EYO, a lower gFC associated with values of amyloid PET, CSF Aβ1-42, CSF p-tau, CSF t-tau, 18F-fluorodeoxyglucose, and hippocampal volume. Conclusions: The gFC correlated with biomarkers used for defining the AT(N) framework. A biphasic change in the gFC suggested early changes associated with CSF amyloid and later changes associated with hippocampal volume.

Hypermetabolism and impaired cerebrovascular reactivity beyond the standard MRI-identified tumor border indicate diffuse glioma extended tissue infiltration.

BackgroundDiffuse gliomas exhibit diffuse infiltrative growth, often beyond the magnetic resonance imaging (MRI)-detectable tumor lesion. Within this lesion, hypermetabolism and impaired cerebrovascular reactivity (CVR) are found, but its exact distribution pattern into the peritumoral environment is unknown. Our aim was to better characterize the extent of diffuse glioma tissue infiltration, beyond the visible lesion (ie, beyond the T1-contrast-enhancing lesion and/or T2/FLAIR-defined tumor border), with metabolic positron emission tomography (PET), and functional MRI CVR (blood oxygenation-level-dependent CVR [BOLD-CVR]) mapping.MethodsFrom a prospective glioma database, 18 subjects (19 datasets) with diffuse glioma (n = 2 with anaplastic astrocytoma, n = 10 with anaplastic oligodendroglioma, and n = 7 with glioblastoma) underwent a BOLD-CVR and metabolic PET study between February 2016 and September 2019, 7 of them at primary diagnosis and 12 at tumor recurrence. In addition, 19 matched healthy controls underwent an identical BOLD-CVR study. The tumor lesion was defined using high-resolution anatomical MRI. Volumes of interest starting from the tumor lesion outward up to 30 mm were created for a detailed peritumoral PET and BOLD-CVR tissue analysis. Student’s t test was used for statistical analysis.ResultsPatients with diffuse glioma exhibit impaired BOLD-CVR 12 mm beyond the tumor lesion (P = .02) with normalization of BOLD-CVR values after 24 mm. Metabolic PET shows a difference between the affected and contralateral hemisphere of 6 mm (P = .05) with PET values normalization after 12 mm.ConclusionWe demonstrate hypermetabolism and impaired CVR beyond the standard MRI-defined tumor border, suggesting active tumor infiltration in the peritumoral environment.

Prediction of Meningioma WHO Grade Using PET Findings: A Systematic Review and Meta-Analysis.

ABSTRACTBackground and PurposeWorld Health Organization (WHO) grading of meningiomas reflects recurrence rate and prognosis. Positron emission tomography (PET) investigates metabolic activity, allowing for distinction between low‐ and high‐grade tumors. As preoperative suspicion for malignant meningioma will influence surgical strategy in terms of timing, extent of resection, and risks taken to achieve a total resection, we systematically reviewed the literature on PET‐imaging in meningiomas and relate these findings to histopathological analysis.MethodsSearches in PubMed, EMBASE, and The Cochrane Library, from inception to September 2019, included studies of patients who had undergone surgery for a histologically verified intracranial meningioma, with a PET‐scan prior to surgery and description of (semi)quantitative PET values for meningiomas from two different WHO groups. Studies comparing more than 1 patient per WHO group were included in the meta‐analysis.ResultsTwenty‐two studies (432 patients) were included. 18fluor‐fluorodesoxyglucose (18F‐FDG) PET was mostly described to differentiate benign from malignant meningiomas. Pooled data showed differences in mean (95% CI) Standardized Uptake Value (SUV) for WHO II/III compared to WHO I of 2.51 (1.36, 3.66), and in tumor‐to‐normal (T/N) ratio (T/N ratio) for WHO II/III versus WHO I of .42 (.12, .73).ConclusionsWe found that SUV and T/N ratio in 18F‐FDG PET may be useful to noninvasively differentiate benign from malignant meningiomas. T/N ratio seems to have a high specificity for the detection of high‐grade meningiomas. Other PET tracers were studied too infrequently to draw definitive conclusions. Before treatment strategies can be adapted based on 18F‐FDG PET, prospective studies in larger cohorts are warranted to validate the optimal T/N ratio cutoff point.

18F-FDOPA-PET in pseudotumoral brain lesions

3,4-Dihydroxy-6-[18F]-fluoro-L-phenylalanine (FDOPA) positron emission tomography (PET) is sensitive for identifying primary brain tumors. However, increased FDOPA uptake has been reported in pseudotumoral brain lesions. Our aim was to analyse FDOPA-PET in patients with pseudotumoral brain lesions and to compare them with patients with brain tumors. We retrospectively analysed consecutively recruited patients with suspected primary brain tumor (based on clinical and magnetic resonance imaging findings) referred for FDOPA-PET in our centre between November 2013 and June 2019 (n = 74). FDOPA-PET parameters (maximum and mean lesion standardised uptake values [SUV] and ratios comparing lesion with different background uptake SUV) and thresholds were evaluated to determine which offered optimal discrimination between pseudotumoral and tumoral lesions. Overlapping PET values were observed between pseudotumoral (n = 26) and tumoral (n = 48) lesion, particularly for low-grade tumors. Based on receiver operating characteristic (ROC) analyses, the optimal PET parameters to discriminate pseudotumoral from tumoral lesions were SUVmax lesion/basal ganglia, SUVmax lesion/grey matter, SUVmean lesion/grey matter, and SUVmax lesion/mirror area in contralateral hemisphere (all ratios showing area under the curve [AUC] 0.85, 95% CI). The narrowest 95% sensitivity-95% specificity window was observed for SUVmax lesion/basal ganglia ratio, with ratio values of 0.79 and 1.35 corresponding to 95% sensitivity and 95% specificity, respectively. FDOPA-PET uptake should be interpreted with caution in patients with suspected primary brain tumor, especially in patients showing low or intermediate SUV values and ratios. CLINICAL TRIAL REGISTRATION-URL: https://www.clinicaltrials.gov . Unique identifier: NCT04306484.

The Additional Value of 18F-FDG PET and MRI in Patients with Glioma: A Review of the Literature from 2015 to 2020.

Aim: Beyond brain computed tomography (CT) scan, Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) hold paramount importance in neuro-oncology. The aim of this narrative review is to discuss the literature from 2015 to 2020, showing advantages or complementary information of fluorine-18 fluorodeoxyglucose (18F-FDG) PET imaging to the anatomical and functional data offered by MRI in patients with glioma. Methods: A comprehensive Pubmed/MEDLINE literature search was performed to retrieve original studies, with a minimum of 10 glioma patients, published from 2015 until the end of April 2020, on the use of 18F-FDG PET in conjunction with MRI. Results: Twenty-two articles were selected. Combined use of the two modalities improves the accuracy in predicting prognosis, planning treatments, and evaluating recurrence. Conclusion: According to the recent literature, 18F-FDG PET provides different and complementary information to MRI and may enhance performance in the whole management of gliomas. Therefore, integrated PET/MRI may be particularly useful in gliomas, since it could provide accurate morphological and metabolic information in one-shoot examination and improve the diagnostic value compared to each of procedures.

Addition of [18 F]Fluorodeoxyglucose Positron Emission Tomography With Computed Tomography to Cross-Sectional Imaging Improves Staging and Alters Management in Hepatocellular Carcinoma.

In this work, we characterize the value of positron emission tomography (PET) with computed tomography (CT) in combination with cross-sectional imaging for staging and prognostication of hepatocellular carcinoma (HCC) patients. In this retrospective cohort study, HCC patients underwent PET-CT after initial staging with contrast-enhanced CT or magnetic resonance imaging (MRI). The benefit of PET-CT was measured by the identification of new HCC lesions, and potential harm was quantified by the number of false positives and subsequent diagnostic evaluation. We used multivariate Cox regression analysis to evaluate the association between the highest grade on PET-CT with the risk of extrahepatic metastasis, progression-free, and overall survival. Among 148 patients, PET-CT detected additional extrahepatic metastasis in 11.9% of treatment-naïve and 13.8% of treatment-experienced patients. PET-CT changed the Barcelona Clinic Liver Cancer (BCLC) staging in 5.9% of treatment-naïve and 18.8% of treatment-experienced patients compared with CT/MRI alone, changing HCC management in 9.9% and 21.3% of patients, respectively. Of the patients, 5% (n=8) experienced severe physical harm requiring additional procedures to evaluate extrahepatic findings. High tumor grade on PET-CT was independently associated with a higher likelihood of extrahepatic metastasis (hazard ratio [HR], 17.1; 95% confidence interval [CI], 3.6-81.5) and worse overall survival (HR, 2.4; 95% CI, 1.4-4.3). Treatment-experienced patients (versus treatment-naïve patients; HR, 9.7; 95% CI, 1.9-49.4) and BCLC stage A (HR, 8.2; 95% CI, 1.5-45.9; P<0.01) and BCLC stage B (HR, 20.6; 95% CI, 1.5-282.2; P<0.05) were more likely to have an upstaging with PET-CT compared with BCLC stage C (reference). PET-CT provides prognostic information and improves tumor staging beyond CT/MRI alone, with subsequent changes in management for patients with HCC.

Baseline 18F-FDG PET radiomic features as predictors of 2-year event-free survival in diffuse large B cell lymphomas treated with immunochemotherapy.

To explore the prognostic value of positron emission tomography (PET) radiomic features in the field of diffuse large B cell lymphoma (DLBCL) treated with a first-line immunochemotherapy. One-hundred thirty-two patients newly diagnosed with DLBCL were retrospectively included. PET studies were reconstructed using an ordered subset expectation maximisation algorithm with point spread function modelling. The total metabolic tumour volume (MTV) was recorded for each patient, and the volume of interest structure of the largest target lesion was used to compute 18F-FDG textural parameters. Data was randomly split into training and validation datasets. Optimal cutoff values were determined by means of 2-year event-free survival (EFS) ROC analyses. Two-year EFS analyses were performed using Kaplan-Meier survival analyses and univariable and multivariable Cox regression models. The median follow-up was 27months, and the 2-year event-free survival (2y-EFS) was 77.3% in the entire population. ROC analyses for the 2y-EFS reached statistical significance for total MTV as well as four second-order metrics (homogeneity, contrast, correlation, dissimilarity) and five third-order metrics (LZE (Long-Zone Emphasis), LZLGE (Long-Zone Low-Grey Level Emphasis), LZHGE (Long-Zone High-Grey Level Emphasis), GLNU (Grey-Level Non-Uniformity) and ZP (Zone Percentage)). LZHGE displayed the highest ROC analysis accuracy (acc. = 0.76) and the best discriminant value on univariable Kaplan-Meier analysis (p < 0.0001, HR = 4.54). On multivariable analysis, including IPIaa, total MTV and LZHGE, LZHGE was the only independent predictor of 2y-EFS. These results were confirmed on the validation dataset. Baseline 18F-FDG PET heterogeneity of the largest lymphoma lesion is a promising predictor of 2y-EFS in newly diagnosed DLBCL treated with immunochemotherapy. •18F-FDG metabolic heterogeneity emerges as a new tool for survival prognostication of patients and has been explored in many solid tumours with promising results. • Baseline18F-FDG PET heterogeneity of the largest lymphoma lesion is an independent predictor of 2y-EFS in newly diagnosed DLBCL treated with immunochemotherapy. • DLBCL patients presenting with a heterogeneous tumour displayed a worse prognosis.

The Role of Positron Emission Tomography in Clinical Management of Intraductal Papillary Mucinous Neoplasms of the Pancreas.

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas represent a heterogeneous group of tumors, increasingly diagnosed in clinical practice. An early differential diagnosis between malignant and benign lesions is crucial to patient management and the choice of surgery or observation. The therapeutic approach is currently based on a patient’s clinical, biochemical, and morphological characteristics. The latest published International Consensus Guidelines (ICG) make no mention of the role of metabolic assessments of IPMNs. The aim of this study was to review the current literature, examining the role of 18-fluorodeoxyglucose (FDG) positron emission tomography (PET) in IPMN management. An extensive literature review was conducted according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and 10 articles were analyzed in detail, focusing on the value of PET as opposed to other standard imaging criteria. Data were retrieved on 419 patients. The 18-FDG-PET proved more sensitive, specific, and accurate than the ICG criteria in detecting malignant IPMNs (reaching 80%, 95%, and 87% vs. 67%, 58%, and 63%, respectively). Metabolic assessments may be used as an additional tool for the appropriate management of patients with doubtful imaging findings.

Correction to: Predictive value of positron emission tomography for the prognosis of immune checkpoint inhibitors (ICIs) in malignant tumors.

The original version of this article unfortunately contained a mistake. The correct information is given in the following.

Predictive value of positron emission tomography for the prognosis of immune checkpoint inhibitors (ICIs) in malignant tumors.

This study aimed at investigating the value of applying positron emission tomography (PET) to early predict the effect of immune checkpoint inhibitors (ICIs) in malignant tumors. Electronic databases MEDLINE/PubMed, EMBASE, and Cochrane Library were searched to identify relevant trials. The primary endpoints were progression-free survival (PFS) and overall survival (OS). The results were analyzed utilizing Stata 12.0 statistical software. Subgroup analyses were implemented based on primarytumors, study designs, continents, type of ICIs, evaluationindex of PET, and evaluated PET timing. Fifteen studies incorporating 664 individuals were eligible. Compared with PET nonresponse group, PET response group displayed a significantly prolonged PFS (HR 0.27, 95% CI [0.16, 0.44]; P < 0.001) and OS (HR 0.56, 95% CI [0.48, 0.65]; P < 0.001). Analogical outcomes were obtained in subgroup analyses of PFS in non-small cell lung cancer, prospective, America, ipilimumab, nivolumab/pembrolizumab combined ipilimumab, PET Response Criteria in Solid Tumors (PERCIST), baseline PET and early PET timing arms without heterogeneity; so did OS in melanoma, retrospective, Europe, America, ipilimumab, nivolumab/pembrolizumab, PERCIST, baseline metabolic tissue volume, baseline standard uptake value, and baseline total lesion glycolysis, baseline PET timing, early PET timing and late PET timing arms. Our study demonstrated that PET was a promising approach to early predict the prognosis of ICIs for malignancies.

Relationship between CT Numbers and Artifacts Obtained Using CT-based Attenuation Correction of PET/CT

The aim of this study was to clarify the artifacts that occurred in the non-activity signal with computed tomography (CT)-based attenuation correction (CTAC) error due to image misregistration. We used a cylindrical phantom containing a test tube with a diameter of 15 mm as the non-activity signal part. Positron emission tomography (PET) images were acquired for 30 minutes using the phantom with water in the non-activity signal part and 18F-fluoro-2-deoxy-d-glucose (18F-FDG) (5.3 kBq/ml) in the background area. CT scanning was performed by replacing the water with contrast agents at different dilutions to obtain arbitrary CT numbers (-1000 to 1000). The PET images were attenuation-corrected individually by the CT images in which the CT number of the non-activity signal part had changed. The relationship between the CT numbers and the CTAC artifact was determined by measuring the PET value in the non-activity signal part of the PET images and comparing Ci. As the CT number of the CT images increased, Ci of the artifact increased. The CT number and Ci had a correlation of y=1.48x+2.86×103 (R2 =0.99) when CTAC was performed in units of CT numbers above 0 for PET data of water (0 HU) and a correlation of y=3.15x+6.26×103 (R2 =0.97) when CTAC was performed in units of CT numbers below 0 for PET data of air (-1000 HU). Although the original CT image was air, the artifacts due to CTAC errors with different Hounsfield units showed larger changes. In particular, positive artifacts were recognized in the PET images after CTAC depending on the Hounsfield units. When the CT number was different from the original in CTAC, the PET value was different. CTAC should be performed with caution as there may be image misregistration.

FDG PET/CT in colorectal cancer

Colorectal cancer (CRC) is the third most frequent cancer worldwide. Although its incidence is increasing, mainly in those aged under 50, mortality has decreased by 50 % in the more developed countries, principally due to the adoption of new practices in prevention, diagnosis and treatment. In particular, the various diagnostic imaging modalities allow improved therapeutic decision-making, evaluation of the response to and efficacy of new therapies and early detection of recurrence. The aim of this paper is to review the available scientific evidence on the value of positron emission tomography with 18F-FDG (18F-FDG PET / CT) in the CCR, with special emphasis on the indications of the guidelines and recommendations of the main international scientific associations regarding this imaging technique.

Prognostic indicators in pancreatic cancer patients undergoing total pancreatectomy.

To evaluate the long-term outcomes of total pancreatectomy in a modern cohort of pancreatic cancer patients and to establish whether any factors identified prior to pancreatic resection were related to poor survival. We analyzed, retrospectively, patients who underwent total pancreatectomy for pancreatic cancer between 2007 and 2016. The short- and long-term outcomes were investigated and Cox regression analysis was used to evaluate the prognostic factors identified before resection. The subjects were 49 patients with a mean age of 65years, who underwent total pancreatectomy in our hospital during the study period. Peritoneal washing cytology was performed in 48 patients, with positive results in 4 (8.3%). There was no 30-day mortality. The median overall survival was 22.5months, with a 5-year survival rate of 28.5%. Univariate analyses of the pre-resection variables revealed that overall survival was associated with tumor location, resectability classification, maximum standardized uptake value of positron emission tomography, the preoperative carbohydrate antigen 19-9 level, and peritoneal washing cytology status. Multivariate analysis revealed that positive peritoneal washing cytology status and the maximum standardized uptake value were independent predictors of poor survival. Total pancreatectomy for pancreatic cancer is appropriate for selected patients, but peritoneal washing cytology and positron emission tomography should be performed preoperatively.

Diagnostic value of computed tomography (CT) and positron emission tomography (PET) for paraaortic lymph node metastasis from left-sided colon and rectal cancer

Paraaortic lymph node (PALN) metastasis influences treatment strategy for colorectal cancer. The aims of this study were to elucidate the diagnostic value of computed tomography (CT) and positron emission tomography (PET) for PALN metastasis from left-sided colorectal cancer. A total of 108 patients who underwent radical surgery including PALN dissection were included. Size and morphology of PALN were evaluated using CT, and presence of higher FDG uptake was evaluated using PET. Findings of CT and PET were compared with pathological status. The largest major axis ≥11mm and heterogeneous internal density were predictive factors on multivariate analysis. Eighty five percent of the PALNs ≥11mm with heterogeneous internal density were pathologically metastatic, whereas 94.1% without them were not metastatic. PET had an accuracy, sensitivity, and specificity of 85.7%, 66.7%, and 94.1%, respectively. In patients with PALNs <11mm without heterogeneous internal density, the accuracy and specificity of PET improved to 93.8% and 96.6%, respectively. Conversely, in patients with some predictive CT findings, although the positive predictive value of PET increased from 83.3% to 88.9%, the accuracy and sensitivity remained at 70.6% and 66.7%, respectively, and 50.0% were false-negatives. CT had high NPV and relatively high PPV. PET had high specificity but low sensitivity. The addition of PET could be useful to confirm no PALN metastasis in patients with no predictive CT findings. Conversely, the improvement of diagnostic ability was limited in patients with some predictive CT findings.

Diagnostic Performance and Prognostic Value of PET/CT with Different Tracers for Brain Tumors: A Systematic Review of Published Meta-Analyses.

Background: Several meta-analyses reporting data on the diagnostic performance or prognostic value of positron emission tomography (PET) with different tracers in detecting brain tumors have been published so far. This review article was written to summarize the evidence-based data in these settings. Methods: We have performed a comprehensive literature search of meta-analyses published in the Cochrane library and PubMed/Medline databases (from inception through July 2019) about the diagnostic performance or prognostic value of PET with different tracers in patients with brain tumors. Results: We have summarized the results of 24 retrieved meta-analyses on the use of PET or PET/computed tomography (CT) with different tracers in brain tumors. The tracers included were: fluorine-18 fluorodeoxyglucose (18F-FDG), carbon-11 methionine (11C-methionine), fluorine-18 fluoroethyltyrosine (18F-FET), fluorine-18 dihydroxyphenylalanine (18F-FDOPA), fluorine-18 fluorothymidine (18F-FLT), and carbon-11 choline (11C-choline). Evidence-based data demonstrated good diagnostic performance of PET with different tracers in detecting brain tumors, in particular, radiolabelled amino acid tracers showed the highest diagnostic performance values. All the PET tracers evaluated had significant prognostic value in patients with glioma. Conclusions: Evidence-based data showed a good diagnostic performance for some PET tracers in specific indications and significant prognostic value in brain tumors.

Texture analysis of pretreatment [18F]FDG PET/CT for the prognostic prediction of locally advanced salivary gland carcinoma treated with interstitial brachytherapy

BackgroundThe aim of this study was to evaluate the prognostic value of positron emission tomography (PET) parameters and the PET texture features of fluorine 18-fluorodeoxyglucose ([18F]FDG) uptake on pretreatment PET/computed tomography (CT) in patients with locally advanced salivary gland carcinoma treated with interstitial brachytherapy.MethodsForty-three patients with locally advanced salivary gland carcinoma of the head and neck were treated with 125I interstitial brachytherapy as the sole modality and underwent [18F]FDG PET/CT scanning before treatment. Tumor segmentation and texture analysis were performed using the 3D slicer software. In total, 54 features were extracted and categorized as first-order statistics, morphology and shape, gray-level co-occurrence matrix, and gray-level run length matrix. Up to November 2018, the follow-up time ranged from 6 to 120 months (median 18 months). Cumulative survival was calculated by the Kaplan-Meier method. Factors between groups were compared by the log-rank test. Multivariate Cox regression analysis with a backward conditional method was used to predict progression-free survival (PFS).ResultsThe 3- and 5-year locoregional control (LC) rates were 55.4% and 37.0%, respectively. The 3- and 5-year PFS rates were 51.2% and 34.1%, respectively. The 3- and 5-year overall survival (OS) rates were 77.0% and 77.0%, respectively. Univariate analysis revealed that minimum intensity, mean intensity, median intensity, root mean square, and long run emphasis (LRE) were significant predictors of PFS, whereas clinicopathological factors, conventional PET parameters, and PET texture features failed to show significance. Multivariate Cox regression analysis showed that minimum intensity and LRE were significant predictors of PFS.ConclusionsThe texture analysis of pretreatment [18F]FDG PET/CT provided more information than conventional PET parameters for predicting patient prognosis of locally advanced salivary gland carcinoma treated with interstitial brachytherapy. The minimum intensity was a risk factor for PFS, and LRE was a favorable factor in prognostic prediction according to the primary results.

Added value of amyloid PET in individualized risk predictions for MCI patients

IntroductionTo construct a prognostic model based on amyloid positron emission tomography (PET) to predict clinical progression in individual patients with mild cognitive impairment (MCI). MethodsWe included 411 MCI patients from the Alzheimer's Disease Neuroimaging Initiative. Prognostic models were constructed with Cox regression with demographics, magnetic resonance imaging, and/or amyloid PET to predict progression to Alzheimer's disease dementia. The models were validated in the Amsterdam Dementia Cohort. ResultsThe combined model (Harrell's C = 0.82 [0.78–0.86]) was significantly superior to demographics (β = 0.100, P < .001), magnetic resonance imaging (β = 0.037, P = .011), and PET only models (β = 0.053, P = .003).The models can be used to calculate individualized risk, for example, a female MCI patient (age = 60, APOE ε4 positive, Mini-Mental State Examination = 25, hippocampal volume = 5.8 cm3, amyloid PET positive) has 35% (19–57) risk in one year and 85% (64–97) risk in three years. Model performances in the Amsterdam Dementia Cohort were reasonable. DiscussionThe present study facilitates the interpretation of an amyloid PET result in the context of a patient's own characteristics and clinical assessment.

Prognostic value of fluorodeoxyglucose positron emission tomography/computed tomography and inguinal sentinel lymph node biopsy in patients with anal cancer.

The aim of this study was to assess the value of positron emission tomography (PET)/CT and sentinel lymph node (SLN) biopsy in staging inguinal lymph nodes in anal cancer patients and to determine if the results of the two methods could be of prognostic value. Sixty-three patients with anal cancer and clinically negative inguinal lymph nodes underwent lymphoscintigraphy and inguinal SLN biopsy and/or fluorodeoxyglucose (FDG) PET/CT scan. All patients were treated with radiotherapy combined with 5-fluorouracil and mitomycin-C. Overall (OS) and disease-free survival (DFS) were 43months (range 5-211) and 43months (range 4-142) respectively. PET/CT examination showed high FDG uptake in the inguinal lymph nodes in 25% of patients. Thirty-five patients with inguinal uptake at lymphoscintigraphy underwent inguinal SLN biopsy and metastatic nodes were found in 31.4%. There was no statistical difference in OS (55 vs 41months; P=0.652) and DFS (48 vs 38months; P=0.992) between the group which showed inguinal uptake on PET/CT and the group which did not, while a positive inguinal SLN was associated with a worse OS (28 vs 59 months; P=0.028) and DFS (56 vs 21 months; P=0.046). When the two examinations were compared PET/CT showed a sensitivity, specificity, positive predictive value and negative predictive value of 22%, 82%, 33% and 73% respectively. The technique of SLN biopsy had a better diagnostic accuracy than total body FDG-PET/CT for the staging of inguinal lymph nodes in anal cancer patients; moreover it was a stronger predictor of OS and DFS than PET/CT.