Active gas features in three HSC-SSP CAMIRA clusters revealed by high angular resolution analysis of MUSTANG-2 SZE and XXL X-ray observations

International audienceWe present results from simultaneous modelling of high angular resolution GBT/MUSTANG-2 90 GHz Sunyaev–Zel’dovich effect (SZE) measurements and XMM-XXL X-ray images of three rich galaxy clusters selected from the HSC-SSP Survey. The combination of high angular resolution SZE and X-ray imaging enables a spatially resolved multicomponent analysis, which is crucial to understand complex distributions of cluster gas properties. The targeted clusters have similar optical richnesses and redshifts, but exhibit different dynamical states in their member galaxy distributions: a single-peaked cluster, a double-peaked cluster, and a cluster belonging to a supercluster. A large-scale residual pattern in both regular Compton-parameter y and X-ray surface brightness distributions is found in the single-peaked cluster, indicating a sloshing mode. The double-peaked cluster shows an X-ray remnant cool core between two SZE peaks associated with galaxy concentrations. The temperatures of the two peaks reach ∼20–30 keV in contrast to the cool core component of ∼2 keV, indicating a violent merger. The main SZE signal for the supercluster is elongated along a direction perpendicular to the major axis of the X-ray core, suggesting a minor merger before core passage. The and y distributions are thus perturbed at some level, regardless of the optical properties. We find that the integrated Compton y parameter and the temperature for the major merger are boosted from those expected by the weak-lensing mass and those for the other two clusters show no significant deviations, which is consistent with predictions of numerical simulations

The JSNM strategies for standardization and harmonization of quantitative whole-body FDG-PET studies

JSNM-JSNMT Joint Symposium, JSNM2017 Yokohama第57回日本核医学会学術総

5-year progress on imaging performance of commercial PET scanners: a multi-center study towards harmonization of FDG-PET

Objectives: Whole-body FDG-PET plays key roles in detection, staging, and characterization of malignant tumors. In oncologic clinical studies and trials, a standardized uptake value (SUV) is often used as a quantitative biomarker although it is considerably affected by many factors such as imaging protocols, PET scanner specifications, and reconstruction parameters. On the other hand, clinical PET scanner performance has rapidly progressed by novel technologies such as point-spread function, time-of-flight, and penalized likelihood reconstruction. To establish a feasible and practical methodology for harmonization of FDG-PET, we are investigating quantitative physical performance of recent clinical PET scanners with the image quality phantom. Here, we compared the recent results with the phantom data that had been acquired about 5 years ago with the PET scanners of those days*.Methods: A total of 19 types of recent commercial PET/CT scanners used in a total of 16 centers were tested in this study. Of these, 15 scanners had TOF measurement capability. A NEMA image quality phantom having six spheres (10–37 mm in diameter) was used for image quality evaluation. The sphere-to-background radioactivity ratio was 4. The background radioactivity concentration was 2.53–2.65 kBq/mL. PET images with various scanning duration (30–300 sec, 1800 sec) were reconstructed using a clinical reconstruction setting in each site. For visual assessment, the PET images were evaluated according to the detectability of the 10-mm hot sphere on a 3-step scale (0, not visualized; 1, visualized, but similar hot spots are observed elsewhere; 2, identifiable) by five observers. We measured the percent contrast of the 10-mm hot sphere (QH,10mm), the background variability (N10mm), the coefficient of variation in the background area (CVBG), and the relative recovery coefficient (RC). The data were compared with the previous data published in 2014* that had been acquired with a total of 13 PET scanners released before 2011.Results: On the PET images with 120 sec acquisition, the median value for all scanners was 2.0 for visual detectability score, 28.7% for QH,10mm, 7.6% for N10mm, and 9.6% for CVBG. Those of the previous data was 0.8 for visual detectability score, 13.7% for QH,10mm, 8.3% for N10mm, and 12.3% for CVBG*. The relative RCs for the spheres with diameters of 22 mm or smaller were higher than the previous data. Overall, the visual detectability of the 10-mm sphere, contrast, image noise, and RC were clearly better than the previous data.Conclusions: We have revealed that imaging performance of commercial PET scanners has made remarkable progress in the past 5 years. For practical harmonization of FDG-PET, regular updates of standard phantom test methodology and harmonizing criteria are essential to adapt to new PET scanners with better imaging performance.(*Fukukita H, et al. Ann Nucl Med. 2014;28:693–705)SNMMI 2020 Annual Meetin

New standards for phantom image quality and SUV harmonization range for multicenter oncology PET studies

Not only visual interpretation for lesion detection, staging, and characterization, but also quantitative treatment response assessment are key roles for 18F-FDG PET in oncology. In multicenter oncology PET studies, image quality standardization and SUV harmonization are essential to obtain reliable study outcomes. Standards for image quality and SUV harmonization range should be regularly updated according to progress in scanner performance. Accordingly, the first aim of this study was to propose new image quality reference levels to ensure small lesion detectability. The second aim was to propose a new SUV harmonization range and an image noise criterion to minimize the inter-scanner and intra-scanner SUV variabilities. We collected a total of 37 patterns of images from 23 recent PET/CT scanner models using the NEMA NU2 image quality phantom. PET images with various acquisition durations of 30–300 s and 1800 s were analyzed visually and quantitatively to derive visual detectability scores of the 10-mm-diameter hot sphere, noise-equivalent count (NECphantom), 10-mm sphere contrast (QH,10 mm), background variability (N10 mm), contrast-to-noise ratio (QH,10 mm/N10 mm), image noise level (CVBG), and SUVmax and SUVpeak for hot spheres (10–37 mm diameters). We calculated a reference level for each image quality metric, so that the 10-mm sphere can be visually detected. The SUV harmonization range and the image noise criterion were proposed with consideration of overshoot due to point-spread function (PSF) reconstruction. We proposed image quality reference levels as follows: QH,10 mm/N10 mm ≥2.5 and CVBG ≤14.1%. The 10th–90th percentiles in the SUV distributions were defned as the new SUV harmonization range. CVBG ≤10% was proposed as the image noise criterion, because the intra-scanner SUV variability signifcantly depended on CVBG. We proposed new image quality reference levels to ensure small lesion detectability. A new SUV harmonization range (in which PSF reconstruction is applicable) and the image noise criterion were also proposed for minimizing the SUV variabilities. Our proposed new standards will facilitate image quality standardization and SUV harmonization of multicenter oncology PET studies. The reliability of multicenter oncology PET studies will be improved by satisfying the new standards

Voxel-based statistical analysis and quantification of amyloid PET in the Japanese Alzheimer\u27s disease neuroimaging initiative (J-ADNI) multi-center study

Background: Amyloid PET plays a vital role in detecting the accumulation of in vivo amyloid-β (Aβ). The quantification of Aβ accumulation has been widely performed using the region of interest (ROI)-based mean cortical standardized uptake value ratio (mcSUVR). However, voxel-based statistical analysis has not been well studied. The purpose of this study was to examine the feasibility of analyzing amyloid PET scans by voxel-based statistical analysis. The results were then compared to those with the ROI-based mcSUVR. In total, 166 subjects who underwent 11C-PiB PET in the J-ADNI multi-center study were analyzed. Additionally, 18 Aβ-negative images were collected from other studies to form a normal database. The PET images were spatially normalized to the standard space using an adaptive template method without MRI. The mcSUVR was measured using a pre-defined ROI. Voxel- wise Z-scores within the ROI were calculated using the normal database, after which Z-score maps were generated. A receiver operating characteristic (ROC) analysis was performed to evaluate whether Z-sum (sum of the Z-score) and mcSUVR could be used to classify the scans into positive and negative using the central visual read as the reference standard. PET scans that were equivocal were regarded as positive. Results: Sensitivity and specificity were respectively 90.8% and 100% by Z-sum and 91.8% and 98.5% by mcSUVR. Most of the equivocal scans were subsequently classified by both Z-sum and mcSUVR as false negatives. Z-score maps correctly delineated abnormal Aβ accumulation over the same regions as the visual read. Conclusions: We examined the usefulness of voxel-based statistical analysis for amyloid PET. This method provides objective Z-score maps and Z-sum values, which were observed to be helpful as an adjunct to visual interpretation especially for cases with mild or limited Aβ accumulation. This approach could improve the Aβ detection sensitivity, reduce inter-reader variability, and allow for detailed monitoring of Aβ deposition

Effects of Capsinoids on Daily Physical Activity, Body Composition and Cold Hypersensitivity in Middle-Aged and Older Adults: A Randomized Study

Sedentary/inactive lifestyle leads middle-aged and older adults to metabolic syndrome and frailty. Capsinoids from nonpungent chili pepper cultivar have been reported to reduce body fat mass, promote metabolism, and improve unidentified complaints of chills. Additionally, they have an anti-inflammation effect; therefore, we hypothesized that continuous oral ingestion of capsinoids alleviates age-related inflammation in the brain and improves the physical activity (PA) in middle-aged and older adults. In our double-blind human study, 69 participants (17 male, 52 female; mean age: 74.1 ± 7.7 years; range: 52–87 years) were administered either 9 mg of capsinoids which were extracted from pepper fruit variety CH-19 Sweet (Capsicum anuum L.) (CP group), or a placebo (PL group) daily over a 3 month period. In an animal study, PA and inflammation-related mRNA expression in the brain were examined in 5-week (young) and 53-week (old) aged mice fed a diet with or without 0.3% dihydrocapsiate, a type of capsinoids, for 12 weeks. In a human study, capsinoids intake did not increase the amount of light-to-moderate PA less than 6.0 metabolic equivalents (METs) (CP: 103.0 ± 28.2 at baseline to 108.2 ± 28.3 at 12 weeks; PL: 104.6 ± 19.8 at baseline to 115.2 ± 23.6 at 12 weeks, METs × hour/week); however, in participants exhibiting an inactive lifestyle, it showed significant increase (CP: 84.5 ± 17.2 at baseline to 99.2 ± 24.9 at 12 weeks; PL: 99.7 ± 23.3 at baseline to 103.8 ± 21.9 at 12 weeks). The energy expenditure in physical activity also improved in the inactive CP group (CP: 481.2 ± 96.3 at baseline to 562.5 ± 145.5 at 12 weeks; PL: 536.8 ± 112.2 at baseline to 598.6 ± 127.6 at 12 weeks; kcal/day). In all participants, CP showed reduced waist circumference, percent body fat, and visceral fat volume; in addition, chills were eased in subjects aged 80 years and older. The older mice fed capsinoids showed increased locomotion activity, decreased inflammation, and oxidative stress in the brain. The results suggest that the continuous oral ingestion of capsinoids gains PA through anti-inflammation effect in the brain as well as reduces fat accumulation and chills in inactive and older humans