Accuracy Of PET Research Articles

Diagnostic Accuracy of FDG PET for the Identification of Vascular Graft Infection

Fluorodeoxyglucose (FDG) positron emission tomography (FDG PET/CT) can be used to identify and localize infection in patients with vascular graft infections (VGI). We aimed to evaluate the diagnostic accuracy of 18F-FDG PET/CT by defining thresholds for standardized uptake value (SUV) and tissue-to-background ratio (TBR) that would accurately identify the presence of vascular graft infection. Patients with suspected VGI were prospectively recruited and underwent 18F-FDG PET/CT scans. Diagnosis was based on clinical, laboratory and radiologic findings, and blinded to the results of the PET/CT scan. Receiver operator characteristics (ROC) curve analysis was done to determine optimal thresholds for SUV and TBR. Our final cohort consisted of 28 patients with suspected VGI (mean±SD age 67±10years, 61% men), of which 15 patients (54%) had definitive VGI. The cohort included 61% prosthetics grafts and 39% stent-grafts. The type of graft included in this study were biologic (4%), Dacron (64%) and Polytetrafluoroethylene (32%). The location of the implanted grafts was aortic (54%) and peripheral arterial reconstruction (46%). The location of the peripheral graft was 77% in lower extremity and 23% in the upper extremity (arterio-venous grafts for dialysis access). Using ROC analysis, SUV max of 4.5, SUV mean of 3.7, and a TBR of 1.6 gave the best balance between sensitivity and specificity (93%/92%, 100%/92% and 93%/92%, respectively). All thresholds had an area under the curve ≥0.93 and correct reclassification rate ≥93%. Our data suggests that FDG PET/CT can be used to reliably and accurately diagnose VGI. The dual anatomic-physiologic information from FDG PET/CT can complement clinical diagnosis particularly in uncertain cases.

Does PET scan have any role in the diagnosis of perineural spread associated with the head and neck tumors?

Perineural spread of head and neck tumors is linked to a worse chance of survival as well as a higher risk of local recurrence and metastasis. Particle emission tomography/computed tomography (PET/CT) using 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) is part of the work-up and follow-up of many afflicted patients, and radiologists play an essential role in the assessment and management of head and neck cancer. The purpose of the current study was to investigate the diagnostic performance of 18F-FDG PET in detecting perineural spread among patients with head and neck tumors through a meta-analysis. Relevant articles were searched using appropriate keywords from PubMed, MEDLINE and PubMed Central (PMC) databases. Retrospective and prospective studies were included as per the predefined PICOS criteria. Demographic summary and event data for diagnostic accuracy of 18F-FDG PET were determined, and odds ratio (OR), sensitivity, specificity, likelihood ratios, and predictive values were calculated using RevMan software. The bias risk was analyzed with Egger's and Begg's tests using MedCalc software. Fourteen clinical trials performed between 2000 and 2021, with 977 head and neck cancer patients with perineural spread, were included according to the inclusion criteria. Included studies used 18F-FDG PET imaging of tumors and reported its high sensitivity. In the current study, we obtained the pooled OR = 3.088 (95% confidence interval (95% CI): [1.486; 6.419]), pooled sensitivity of 91.7%, pooled specificity of 92.35%, positive predictive value (PPV) of 92.27%, negative predictive value (NPV) of 91.13%, positive likelihood ratio of 7.45, negative likelihood ratio of 0.28, disease prevalence of 95.8%, and accuracy of 91.5%. Data was heterogeneous, with Q value of 33.8%, degrees of freedom (df) value of 13, I2 value of 61.5% (31.23-78.5), and p-value = 0.0013. The risk of publication bias was low, with a p = 0.7490 (Egger's test) and p = 0.7843 (Begg's test). The present meta-analysis highly recommends 18F-FDG PET as an effective imaging method for patients with head and neck tumors with perineural spread.

A reference tissue forward model for improved PET accuracy using within-scan displacement studies

We report a novel forward-model implementation of the full reference tissue model (fFTRM) that addresses the fast-exchange approximation employed by the simplified reference tissue model (SRTM) by incorporating a non-zero dissociation time constant from the specifically bound compartment. The forward computational approach avoided errors associated with noisy and nonorthogonal basis functions using an inverse linear model. Compared to analysis by a multilinear single-compartment reference tissue model (MRTM), fFTRM provided improved accuracy for estimation of binding potentials at early times in the scan, with no worse reproducibility across sessions. To test the model’s ability to identify small focal changes in binding potential using a within-scan challenge, we employed a nonhuman primate model of focal dopamine release elicited by deep brain microstimulation remote to ventral striatum (VST) during imaging by simultaneous PET and fMRI. The new model reported an unambiguously lateralized response in VST consistent with fMRI, whereas the MRTM-derived response was not lateralized and was consistent with simulations of model bias. The proposed model enabled better accuracy in PET [11C]raclopride displacement studies and may also facilitate challenges sooner after injection, thereby recovering some sensitivity lost to radioactive decay of the PET tracer.

Quantification of myocardial perfusion reserve by CZT-SPECT: A head to head comparison with 82Rubidium PET imaging

BackgroundWe measured myocardial blood flow (MBF) and perfusion reserve (MPR) by dynamic CZT-SPECT and 82Rb-PET in patients with suspected or known coronary artery disease (CAD) and compared the accuracy of the two methods in predicting obstructive CAD. MethodsTwenty-five patients with available coronary angiography data underwent 99mTc-sestamibi CZT-SPECT and 82Rb-PET cardiac imaging. Stress and rest MBF and MPR were calculated by both methods and compared. Diagnostic accuracies of CZT-SPECT and PET were also assessed using a receiver-operator-characteristic curve. ResultsCZT-SPECT yielded similar baseline MBF, but higher hyperemic MBF and MPR values compared to PET. There was a modest correlation between the two methods for MPR (r = 0.56, P < .01). MPR by CZT-SPECT showed a good ability in identify a reduced MPR by PET, with an area under the curve of 0.85. A MPR cut-off of 2.5 was identified by CZT-SPECT for detection of abnormal MPR by PET, with a sensitivity, specificity and accuracy of 86%, 73% and 80%. The area under the curve for the identification of obstructive CAD by regional MPR were 0.83 for CZT-SPECT and 0.84 for PET (P = .90). At CZT-SPECT, a regional MPR of 2.1 provided the best trade-off between sensitivity and specificity for identifying obstructive CAD. Diagnostic accuracy of CZT-SPECT and PET using respective cut-off values was comparable (P = .62). ConclusionHyperemic MBF and MPR values obtained by CZT-SPECT are higher than those measured by 82Rb-PET imaging, with a moderate correlation between the two methods. CZT-SPECT shows good diagnostic accuracy for the identification of obstructive CAD. These findings may encourage the use of this new technique to a better risk stratification and patient management.

Boosting the diagnostic power of amyloid-\u03b2 PET using a data-driven spatially informed classifier for decision support

BackgroundAmyloid-β (Aβ) PET has emerged as clinically useful for more accurate diagnosis of patients with cognitive decline. Aβ deposition is a necessary cause or response to the cellular pathology of Alzheimer’s disease (AD). Usual clinical and research interpretation of amyloid PET does not fully utilise all information regarding the spatial distribution of signal. We present a data-driven, spatially informed classifier to boost the diagnostic power of amyloid PET in AD.MethodsVoxel-wise k-means clustering of amyloid-positive voxels was performed; clusters were mapped to brain anatomy and tested for their associations by diagnostic category and disease severity with 758 amyloid PET scans from volunteers in the AD continuum from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). A machine learning approach based on this spatially constrained model using an optimised quadratic support vector machine was developed for automatic classification of scans for AD vs non-AD pathology.ResultsThis classifier boosted the accuracy of classification of AD scans to 81% using the amyloid PET alone with an area under the curve (AUC) of 0.91 compared to other spatial methods. This increased sensitivity to detect AD by 15% and the AUC by 9% compared to the use of a composite region of interest SUVr.ConclusionsThe diagnostic classification accuracy of amyloid PET was improved using an automated data-driven spatial classifier. Our classifier highlights the importance of considering the spatial variation in Aβ PET signal for optimal interpretation of scans. The algorithm now is available to be evaluated prospectively as a tool for automated clinical decision support in research settings.

Diagnostic Performance of [18F]FDG PET in Staging Grade 1-2, Estrogen Receptor Positive Breast Cancer.

Positron emission tomography using [18F]fluorodeoxyglucose (FDG PET) potentially underperforms for staging of patients with grade 1–2 estrogen receptor positive (ER+) breast cancer. The aim of this study was to retrospectively investigate the diagnostic accuracy of FDG PET in this patient population. Suspect tumor lesions detected on conventional imaging and FDG PET were confirmed with pathology or follow up. PET-positive lesions were (semi)quantified with standardized uptake values (SUV) and these were correlated with various pathological features, including the histological subtype. Pre-operative imaging detected 155 pathologically verified lesions (in 74 patients). A total of 115/155 (74.2%) lesions identified on FDG PET were classified as true positive, i.e., malignant (in 67 patients) and 17/155 (10.8%) lesions as false positive, i.e., benign (in 9 patients); 7/155 (4.5%) as false negative (in 7 patients) and 16/155 (10.3%) as true negative (in 14 patients). FDG PET incorrectly staged 16/70 (22.9%) patients. The FDG uptake correlated with histological subtype, showing higher uptake in ductal carcinoma, compared to lobular carcinoma (p < 0.05). Conclusion: Within this study, FDG PET inadequately staged 22.9% of grade 1–2, ER + BC cases. Incorrect staging can lead to inappropriate treatment choices, potentially affecting survival and quality of life. Prospective studies investigating novel radiotracers are urgently needed.

Diagnostic Test Accuracy of 18F-FDG PET or PET/CT for Characterization of Histologic Type of Thymic Epithelial Tumor: A Meta-analysis.

This study investigated diagnostic accuracies of 18F-FDG PET or PET/CT for characterization of histologic type of thymic epithelial tumors (TETs) through a systematic review and meta-analysis. The PubMed, Cochrane database, and EMBASE database, from the earliest available date of indexing through August 31, 2020, were searched for studies evaluating diagnostic performance of 18F-FDG PET or PET/CT for characterization of TET. We determined the sensitivities and specificities, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves. The pooled sensitivity of 18F-FDG PET or PET/CT was 0.89 (95% confidence interval [CI], 0.80-0.95), and the pooled specificity was 0.77 (95% CI, 0.63-0.87) for differentiation between thymic cancer and thymoma. Likelihood ratio syntheses gave an overall positive likelihood ratio (LR+) of 3.9 and negative likelihood ratio (LR-) of 0.14. The pooled diagnostic odds ratio was 28 (95% CI, 13-63). The pooled sensitivity was 0.90 (95% CI, 0.75-0.96), and the pooled specificity was 0.81 (95% CI, 0.68-0.89) for differential diagnosis of a low-risk or high-risk TET. LR+ was 4.7 and LR- was 0.12. The pooled diagnostic odds ratio was 38 (95% CI, 12-121). In meta-regression analysis, no variable was the source of the study heterogeneity. 18F-FDG PET or PET/CT has excellent diagnostic performances for characterization of TET. Further large multicenter studies would be necessary to establish the diagnostic accuracy of 18F-FDG PET or PET/CT for differentiation of histologic type of TET.

Yttrium-90 quantitative phantom study using digital photon counting PET

BackgroundPET imaging of 90Y-microsphere distribution following radioembolisation is challenging due to the count-starved statistics from the low branching ratio of e+/e− pair production during 90Y decay. PET systems using silicon photo-multipliers have shown better 90Y image quality compared to conventional photo-multiplier tubes. The main goal of the present study was to evaluate reconstruction parameters for different phantom configurations and varying listmode acquisition lengths to improve quantitative accuracy in 90Y dosimetry, using digital photon counting PET/CT.MethodsQuantitative PET and dosimetry accuracy were evaluated using two uniform cylindrical phantoms specific for PET calibration validation. A third body phantom with a 9:1 hot sphere-to-background ratio was scanned at different activity concentrations of 90Y. Reconstructions were performed using OSEM algorithm with varying parameters. Time-of-flight and point-spread function modellings were included in all reconstructions. Absorbed dose calculations were carried out using voxel S-values convolution and were compared to reference Monte Carlo simulations. Dose-volume histograms and root-mean-square deviations were used to evaluate reconstruction parameter sets. Using listmode data, phantom and patient datasets were rebinned into various lengths of time to assess the influence of count statistics on the calculation of absorbed dose. Comparisons between the local energy deposition method and the absorbed dose calculations were performed.ResultsUsing a 2-mm full width at half maximum post-reconstruction Gaussian filter, the dosimetric accuracy was found to be similar to that found with no filter applied but also reduced noise. Larger filter sizes should not be used. An acquisition length of more than 10 min/bed reduces image noise but has no significant impact in the quantification of phantom or patient data for the digital photon counting PET. 3 iterations with 10 subsets were found suitable for large spheres whereas 1 iteration with 30 subsets could improve dosimetry for smaller spheres.ConclusionThe best choice of the combination of iterations and subsets depends on the size of the spheres. However, one should be careful on this choice, depending on the imaging conditions and setup. This study can be useful in this choice for future studies for more accurate 90Y post-dosimetry using a digital photon counting PET/CT.

Results of DETECTYON study: Diagnostic accuracy of 68GA PET, endoscopic ultrasound (EUS) and CT scan in the assessment of lymph node metastases from non functioning pancreatic neuroendocrine neoplasms

Results of DETECTYON study: Diagnostic accuracy of 68GA PET, endoscopic ultrasound (EUS) and CT scan in the assessment of lymph node metastases from non functioning pancreatic neuroendocrine neoplasms

A bicentric retrospective analysis of clinical utility of 18F-fluciclovine PET in biochemically recurrent prostate cancer following primary radiation therapy: is it helpful in patients with a PSA rise less than the Phoenix criteria?

18F-Fluciclovine PET imaging has been increasingly used in the restaging of prostate cancer patients with biochemical recurrence (BCR); however, its clinical utility in patients with low prostate-specific antigen (PSA) levels following primary radiation therapy has not been well-studied. This study aims to determine the detection rate and diagnostic accuracy of 18F-fluciclovine PET and the patterns of prostate cancer recurrence in patients with rising PSA after initial radiation therapy, particularly in patients with PSA levels below the accepted Phoenix definition of BCR (PSA nadir +2ng/mL). This retrospective study included patients from two tertiary institutions who underwent 18F-fluciclovine PET scans for elevated PSA level following initial external beam radiation therapy, brachytherapy, and/or proton therapy. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to determine the diagnostic accuracy of 18F-fluciclovine PET and associations of PSA kinetic parameters with 18F-fluciclovine PET outcome. One hundred patients were included in this study. The overall detection rate on a patient-level was 79% (79/100). 18F-Fluciclovine PET was positive in 62% (23/37) of cases with PSA below the Phoenix criteria. The positive predictive value of 18F-fluciclovine PET was 89% (95% CI: 80-94%). In patients with PSA below the Phoenix criteria, the PSA velocity had the highest predictive value of 18F-fluciclovine PET outcome. PSA doubling time (PSADT) and PSA velocity were associated with the presence of extra-pelvic metastatic disease. 18F-Fluciclovine PET can identify recurrent disease at low PSA level and PSA rise below accepted Phoenix criteria in patients with suspected BCR after primary radiation therapy, particularly in patients with low PSADT or high PSA velocity. In patients with low PSADT or high PSA velocity, there is an increased probability of extra-pelvic metastases. Therefore, these patients are more likely to benefit from PET/CT or PET/MRI than pelvic MRI alone.

Diagnostic role of PET or PET/CT for prosthetic joint infection: A systematic review and Meta-analysis.

We aimed to explore the role of the diagnostic accuracy of positron emission tomography/computed tomography (PET/CT) or PET for the detection of periprosthetic infection (PPI) of lower limb arthroplasty through a systematic review and meta-analysis. The MEDLINE and EMBASE from the earliest available date of indexing through October 31, 2020, were searched for studies evaluating the diagnostic performance of PET or PET/CT for the detection of PPI of lower limb arthroplasty. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves. Across 25 results of 19 studies (826 patients), the pooled sensitivity for PET or PET/CT was 0.88 (95% CI; 0.80-0.93) with heterogeneity (χ2=119, P=0.00) and a pooled specificity of 0.89 (95% CI; 0.83-0.93) with heterogeneity (χ22=170, P=0.00). Likelihood ratio syntheses gave an overall positive LR+ of 7.9 (95% CI; 5.1-12.2) and negative LR- of 0.14 (95% CI; 0.08-0.23). The pooled DOR was 57 (95% CI; 31-106). The PET or PET/CT demonstrated good sensitivity and specificity for the detection of PPI of lower limb arthroplasty. At present, the literature regarding the use of PET or PET/CT for the detection of PPI of lower limb arthroplasty remains still limited; thus, further large multicenter studies would be necessary to substantiate the diagnostic accuracy of PET or PET/CT for the detection of PPI of lower limb arthroplasty.

Využití PET/ CT v diagnostice vzdálených metastáz a duplicitních nádorů v onkologii hlavy a krku PDF uzamčeno English info

Aim: Our goal was to assess our experience with accuracy of PET/ CT in the dia­gnostics of distant metastases and duplicity tumors in head and neck oncology. Methods: In total, 159 patients with a previously histologically verified malignant tumor of the head and neck underwent whole-body PET/ CT in our facility from 2016 to 2019. In 51 cases, we found out higher uptake of marked radiopharmaceutical (fluorodeoxyglucose) out of the head and neck region. In a retrospective study, we were evaluating the sensitivity and specificity of the method in the dia­gnostics of distant metastases and duplicities. Results: In our study, PET/ CT has sensitivity of 95.7% and specificity of 79.9% with positive and negative predictive values of 44.9% and 99.1% respectively. Conclusion: The method has a high sensitivity but lower specificity rate in the dia­gnostics of distant metastases (duplicity tumors) in head and neck oncology. Considering high radiation load and the price and availability of PET/ CT, it is necessary to consider the indication of this technique properly.

Accuracy of 18F-Fluorocholine PET for the Detection of Parathyroid Adenomas: Prospective Single-Center Study.

The purpose of this prospective study was to determine the correct localization rate (CLR) of 18F-fluorocholine PET for the detection of parathyroid adenomas in comparison to 99mTc-sestamibi imaging. Methods: This was a single-arm prospective trial. Ninety-eight patients with biochemical evidence of primary hyperparathyroidism were imaged before parathyroidectomy using 18F-fluorocholine PET/MRI. 99mTc-sestamibi imaging performed separately from the study was evaluated for comparison. The primary endpoint of the study was the CLR on a patient level. Each imaging study was interpreted by 3 masked readers on a per-region basis. Lesions were validated by histopathologic analysis of surgical specimens. Results: Of the 98 patients who underwent 18F-fluorocholine PET, 77 subsequently underwent parathyroidectomy and 60 of those had 99mTc-sestamibi imaging. For 18F-fluorocholine PET in patients who underwent parathyroidectomy, the CLR based on the masked reader consensus was 75% (95% CI, 0.63-0.82). In patients who underwent surgery and had an available 99mTc-sestamibi study, the CLR increased from 17% (95% CI, 0.10-0.27) for 99mTc-sestamibi imaging to 70% (95% CI, 0.59-0.79) for 18F-fluorocholine PET. Conclusion: In this prospective study using masked readers, the CLR for 18F-fluorocholine PET was 75%. In patients with a paired 99mTc-sestamibi study, the use of 18F-fluorocholine PET increased the CLR from 17% to 70%. 18F-fluorocholine PET is a superior imaging modality for the localization of parathyroid adenomas.

P07.01 Less Accuracy of CT and PET in the Evaluation of N1 Node may Result in Overlooking Skip Metastasis of Single Station cN2 Non-Small Cell Lung Cancer

P07.01 Less Accuracy of CT and PET in the Evaluation of N1 Node may Result in Overlooking Skip Metastasis of Single Station cN2 Non-Small Cell Lung Cancer

Improving accuracy of 18F-fluorodeoxyglucose PET computed tomography to diagnose nodal involvement in non-small cell lung cancer: utility of using various predictive models.

To determine predictive models (PM) that could improve the accuracy for identifying metastatic regional nodes in non-small cell lung cancer based on both PET and CT findings seen on 18F-FDG PET CT. Three hundred thirty-nine biopsy-proven NSCLC patients who underwent surgical resection and had a staging 18F-FDG PET CT were enrolled. PET parameters obtained were (1) presence of visual PET positive nodes, (2) SUVmax of nodes (NSUV), (3) ratio of node to aorta SUVmax (N/A ratio) and (4) ratio of node to primary tumour SUVmax (N/T ratio). CT parameters obtained were (1) short-axis diameter and (2) Hounsfield units (HU) of PET-positive nodes. PET and CT parameters were correlated with nodal histopathology to find out the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy. Different PM combining these parameters were devised and the incremental improvement in accuracy was determined. Visual PET positivity showed sensitivity, specificity, PPV, NPV and accuracy of 72.4, 76.1, 30.1, 95.1 and 75.6, respectively. PM2 which combined visual PET positivity, NSUV and HU appears more clinically relevant and showed sensitivity, specificity, PPV, NPV and accuracy of 53.5, 96.5, 68.9, 93.6 and 91.2, respectively. PM6 which combined visual PET positivity, NSUV, N/A ratio and HU showed the maximum PPV (80.0%), specificity (98.3%) and accuracy of (91.9%). PM combining parameters like nodal SUVmax, N/A ratio, N/T ratio and HU values have shown to improve the PPV, specificity and overall accuracy of 18FDG PET CT in the preoperative diagnosis of nodal metastases.

Simulation of Low-Dose Protocols for Myocardial Perfusion 82Rb Imaging.

Quantification of myocardial perfusion and myocardial blood flow using 82Rb PET is increasingly used for assessment of coronary artery disease. Current guidelines suggest injections of 1,100-1,500 MBq for both stress and rest. Reducing the injected dose avoids PET system saturation in first-pass flow images and reduces radiation exposure, but the impact on myocardial perfusion quantification of static perfusion images is not fully understood. In this study, we aimed to evaluate the feasibility of performing myocardial perfusion scans using either a half-dose (HfD) or quarter-dose (QD) protocol using reconstructions from acquired full-dose (FD) scans. Methods: This study comprised 171 patients who underwent rest/stress 82Rb PET with a 3-dimensional 4-ring PET/CT scanner using a FD protocol and invasive coronary angiography within 6 mo of the PET emission scan. HfD and QD reconstructions were obtained using the prescribed percentage of events from the FD list-mode files. The total perfusion deficit was quantified for rest (rTPD), stress (sTPD), and ischemia (ITPD = sTPD - rTPD). Diagnostic accuracy for obstructive coronary artery disease, defined as at least 70% stenosis in any of the 3 major coronary arteries, was compared with area under the receiver-operating-characteristic curve (AUC). Results: Patients with a median body mass index of 28.0 (interquartile range, 23.9-31.7) were injected with doses of 1,165 ± 189 MBq of 82Rb. For sTPD, FD and HfD protocols had similar AUCs (FD, 0.807; HfD, 0.802; P = 0.108), whereas QD had a reduced AUC (0.786, P = 0.037). There was no difference in the AUC obtained for ITPD among the 3 protocols (FD, 0.831; HfD, 0.835; QD, 0.831; all P ≥ 0.805). Conclusion: HfD imaging does not affect the quantitative diagnostic accuracy of 82Rb PET on 3-dimensional PET/CT systems and could be used clinically.

Prediction of lymph node involvement in epithelial ovarian cancer by PET/CT, CT and MRI imaging

Objective: The aim of this study is to detect retroperitoneal metastatic lymph nodes in epithelial ovarian cancer with preoperative imaging methods (MRI, CT, 18F-FDG PET/CT). Material and method: Patients with epithelial ovarian cancer followed by the Akdeniz University Faculty of Medicine Gynecologic Oncology Surgery Department registered in the hospital’s electronic file system, who had undergone pelvic and/or paraaortic lymphadenectomy, and having undergone at least one imaging method (MRI, CT, PET/CT), were included in the study. Based on the data available, 89 patients were included in the study. Lymph node metastasis in the histopathology reports of these patients was accepted as the gold standard. The presence of lymph nodes on the imaging modalities (MRI, CT, PET/CT) was regarded as positive and was compared with the gold standard pathological lymph node metastasis. By doing so, the accuracy, specificity, sensitivity, PPV and the NPV of the imaging methods in predicting lymph node metastasis were calculated. Findings: Thirty-eight (42.7%) of 89 patients included in our study were at stage 3C. Based on the data, while 85 of the 89 patients included in the study obtained had undergone pelvic and paraaortic lymphadenectomy, four patients had undergone only pelvic lymphadenectomy. Of the patients, 73 had undergone a CT, 20 had undergone a PET/CT and 12 had undergone an MRI. The sensitivity, specificity, PPV, NPV and the accuracy of CT regarding all nodal involvement was 62%, 52%, 57%, 57%, and 57%, respectively. The PET/CT’s values were 63%, 66%, 70%, 60% and 65%, respectively. The sensitivity, specificity, PPV, NPV and the accuracy of PET regarding paraaortic nodal involvement alone were 50%, 91%, 80%, 73% and 75%, respectively. Conclusion: According to the data we obtained, it is challenging to decide whether to perform systemic pelvic and paraaortic lymphadenectomy based on imaging modalities (MRI, CT, PET/CT), and hence, further investigation is needed for more accurate imaging techniques.

Assessment of Central Nervous System Lymphoma Based on CXCR4 Expression In Vivo Using 68Ga-Pentixafor PET/MRI.

F-FDG PET is limited for assessment of central nervous system lymphoma (CNSL) due to physiologic tracer accumulation in the brain. We prospectively evaluated the novel PET tracer Ga-pentixafor, which targets the C-X-C chemokine receptor 4 (CXCR4), for lesion visualization and response assessment of CNSL. Seven CNSL patients underwent Ga-pentixafor PET/MRI with contrast enhancement (CE-MRI) and diffusion-weighted sequences. The accuracy of Ga-pentixafor PET for CNSL lesion detection relative to the CE-MRI reference standard was determined. Standardized uptake values (SUVmean and SUVmax), PET-based (PTV) and MRI-based (VOLMRI) tumor volumes, and apparent diffusion coefficients (ADCs) were assessed, and correlation coefficients were calculated. Three SUVmax thresholds (41%, 50%, and 70%) were evaluated for PTV definitions (PTV41%, PTV50%, and PTV70%) and tested against VOLMRI using paired sample t tests. Twelve Ga-pentixafor PET/MRI examinations (including 5 follow-up scans) of 7 patients were evaluated. Ga-pentixafor PET demonstrated 18 lesions, all of which were confirmed by CE-MRI; there were no false-positive lesions on PET (accuracy, 100%). PTV41% showed the highest concordance with lesion morphology, with no significant difference compared with VOLMRI (mean difference, -0.24 cm; P = 0.45). The correlation between ADCmean and SUVmean41% (r = 0.68) was moderate. Changes in PTV41% on follow-up PET/MRI showed the same trend as VOLMRI changes, including progression of 1 lesion each in patient 1 (+456.0% PTV41% and +350.8% VOLMRI) and patient 3 (+110.4% PTV41% and +85.1% VOLMRI). Ga-pentixafor PET may be feasible for assessment and follow-up of CNSL. Future studies need to focus on testing its clinical value to distinguish between glioma and CNSL, and between radiation-induced inflammation and viable residual tumor.

PET–CT for staging patients with muscle invasive bladder cancer: is it more than just a fancy tool?

We aim to evaluate the diagnostic accuracy of PET–CT/MRI in the local and distant staging of patients with muscle invasive bladder cancer (MIBC). Medline, Pubmed and EMBASE were searched for studies evaluating the diagnostic performance of PET–CT/MRI in the primary staging of MIBC patients. The pooled sensitivity, specificity, positive and negative likelihood ratio (PLR and NLR, respectively) and diagnostic odds ratio (DOR = PLR/NLR) are reported. We retrieved 35 articles. For local staging, a pooled sensitivity and specificity of 88% (95% CI: 81–92%) and 68% (95% CI: 50–82%), respectively, were found. The PLR and NLR are 2.88 (95% CI: 1.71–4.73) and 0.19 (95% CI: 0.12–0.30) resulting in a DOR of 16.60 (95% CI: 5.98–37.50). For regional lymph node staging, the pooled sensitivity and specificity are 57% (95% CI: 5–63%) and 89% (95% CI: 83–3%). The PLR is 5.33 (95% CI: 3.44–8.09) and NLR is 0.48 (95% CI: 0.42–0.55). The corresponding DOR is 11.10 (95% CI: 6.62–17.60). For distant metastases, a pooled sensitivity and specificity of 89% (95% CI: 61–98%) and 95% (95% CI: 80–99%), respectively, were found. The PLR is 23.70 (95% CI: 4.19–72.10) and the NLR is 0.13 (95% CI: 0.02–0.36) with a DOR of 236.00 (95% CI: 38.00–871.00). PET–CT/MRI appears to have higher diagnostic accuracy than CT or MRI for local and distant staging of MIBC but it cannot (yet) be recommended in clinical practice because the quality of the evidence is insufficient and the effects on treatment decisions and patient’s outcome remain unclear.

Diagnostic Yield of 18F-FDG PET After Lung Transplantation: A Single-center, Retrospective Cohort Study.

To investigate the diagnostic yield of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in lung transplant recipients. A single-center, retrospective cohort study including 234 18F-FDG PET examinations in 199 lung transplant recipients. Indication for PET referral, 18F-FDG PET diagnosis/findings and final clinical diagnosis were classified into 3 groups: malignancy, infection/inflammation not otherwise specified, and chronic lung allograft dysfunction with restrictive allograft syndrome phenotype. Sensitivity/specificity analysis was performed to determine accuracy of 18F-FDG PET in each group. Sensitivity of 18F-FDG PET for malignancy was 91.4% (95% confidence interval, 82.5%-96.0%) and specificity was 82.3% (95% confidence interval, 74.5%-88.1%). Infection/inflammation not otherwise specified and restrictive allograft syndrome as indication for 18F-FDG PET comprised relatively small groups (14 and 31 cases, respectively). In addition, 18F-FDG PET revealed clinically relevant incidental findings in 15% of cases. Referral for 18F-FDG PET after lung transplantation mainly occurred to confirm or rule out malignancy. In this specific setting, 18F-FDG PET has a high diagnostic yield. Accuracy of 18F-FDG PET for other indications is less clear, given small sample sizes. Clinically relevant diagnoses, unrelated to the primary indication for 18F-FDG PET, are found relatively often in this immunocompromised cohort.