Min Scan Research Articles

Synthesis of Prospective Multiple Time Points F-18 FDG PET Images from a Single Scan Using a Supervised Generative Adversarial Network.

The cumulative activity map estimation are essential tools for patient specific dosimetry with high accuracy, which is estimated using biokinetic models instead of patient dynamic data or the number of static PET scans, owing to economical and time-consuming points of view. In the era of deep learning applications in medicine, the pix-to-pix (p2 p) GAN neural networks play a significant role in image translation between imaging modalities. In this pilot study, we extended the p2 p GAN networks to generate PET images of patients at different times according to a 60 min scan time after the injection of F-18 FDG. In this regard, the study was conducted in two sections: phantom and patient studies. In the phantom study section, the SSIM, PSNR, and MSE metric results of the generated images varied from 0.98-0.99, 31-34 and 1-2 respectively and the fine-tuned Resnet-50 network classified the different timing images with high performance. In the patient study, these values varied from 0.88-0.93, 36-41 and 1.7-2.2, respectively and the classification network classified the generated images in the true group with high accuracy. The results of phantom studies showed high values of evaluation metrics owing to ideal image quality conditions. However, in the patient study, promising results were achieved which showed that the image quality and training data number affected the network performance. This study aims to assess the feasibility of p2 p GAN network application for different timing image generation.

In Vivo Imaging and Kinetic Modeling of Novel Glycogen Synthase Kinase-3 Radiotracers [11C]OCM-44 and [18F]OCM-50 in Non-Human Primates.

Glycogen synthase kinase 3 (GSK-3) is a potential therapeutic target for a range of neurodegenerative and psychiatric disorders. The goal of this work was to evaluate two leading GSK-3 positron emission tomography (PET) radioligands, [11C]OCM-44 and [18F]OCM-50, in non-human primates to assess their potential for clinical translation. A total of nine PET scans were performed with the two radiotracers using arterial blood sampling in adult rhesus macaques. Brain regional time-activity curves were extracted and fitted with one- and two-tissue compartment models using metabolite-corrected arterial input functions. Target selectivity was assessed after pre-administration of the GSK-3 inhibitor PF-04802367 (PF-367, 0.03-0.25 mg/kg). Both radiotracers showed good brain uptake and distribution throughout grey matter. [11C]OCM-44 had a free fraction in the plasma of 3% at baseline and was metabolized quickly. The [11C]OCM-44 volume of distribution (VT) values in the brain increased with time; VT values from models fitted to truncated 60-min scan data were 1.4-2.9 mL/cm3 across brain regions. The plasma free fraction was 0.6% for [18F]OCM-50 and VT values (120-min) were 0.39-0.87 mL/cm3 in grey matter regions. After correcting for plasma free fraction increases during blocking scans, reductions in regional VT indicated >80% target occupancy by 0.1 mg/kg of PF-367 for both radiotracers, supporting target selectivity in vivo. [11C]OCM-44 and [18F]OCM-50 warrant further evaluation as radioligands for imaging GSK-3 in the brain, though radio-metabolite accumulation may confound image analysis.

Rapid microscopic 3D-diffusion tensor imaging fiber-tracking of mouse brain in vivo by super resolution reconstruction: validation on MAP6-KO mouse model.

Exploring mouse brains by rapid 3D-Diffusion Tensor Imaging (3D-DTI) of high spatial resolution (HSR) is challenging in vivo. Here we use the super resolution reconstruction (SRR) postprocessing method to demonstrate its performance on Microtubule-Associated-Protein6 Knock-Out (MAP6-KO) mice. Two spin-echo DTI were acquired (9.4T, CryoProbe RF-coil): (i)-multislice 2D-DTI, (echo-planar integrating reversed-gradient) acquired in vivo in the three orthogonal orientations (360μm slice-thickness, 120 × 120μm in-plane resolution, 56min scan duration); used in SRR software to reconstruct SRR 3D-DTI with HSR in slice-plane (120 × 120 × 120µm) and (ii)-microscopic 3D-DTI (µ-3D-DTI), (100 × 100 × 100µm; 8h 6min) on fixed-brains ex vivo, that were removed after paramagnetic contrast-agent injection to accelerate scan acquisition using short repetition-times without NMR-signal sensitivity loss. White-matter defects, quantified from both 3D-DTI fiber-tracking were found very similar. Indeed, as expected the fornix and cerebral-peduncle volume losses were -39% and -35% in vivo (SRR 3D-DTI) versus -34% and -32% ex vivo (µ-3D-DTI), respectively (p<0.001). This finding is robust since the µ-3D-DTI feasibility on MAP6-KO ex vivo was already validated by fluorescent-microscopy of cleared brains. First performance of the SRR to generate rapid HSR 3D-DTI of mouse brains in vivo is demonstrated. The method is suitable in neurosciences for longitudinal studies to identify molecular and genetic abnormalities in mouse models that are of growing developments.

Machine learning-based approach reveals essential features for simplified TSPO PET quantification in ischemic stroke patients

IntroductionNeuroinflammation evaluation after acute ischemic stroke is a promising option for selecting an appropriate post-stroke treatment strategy. To assess neuroinflammation in vivo, translocator protein PET (TSPO PET) can be used. However, the gold standard TSPO PET quantification method includes a 90 min scan and continuous arterial blood sampling, which is challenging to perform on a routine basis. In this work, we determine what information is required for a simplified quantification approach using a machine learning algorithm. Materials and MethodsWe analyzed data from 18 patients with ischemic stroke who received 0–90 min [18F]GE-180 PET as well as T1-weigted (T1w), FLAIR, and arterial spin labeling (ASL) MRI scans. During PET scans, five manual venous blood samples at 5, 15, 30, 60, and 85 min post injection (p.i.) were drawn, and plasma activity concentration was measured. Total distribution volume (VT) was calculated using Logan plot with the full dynamic PET and an image-derived input function (IDIF) from the carotid arteries. IDIF was scaled by a calibration factor derived from all the measured plasma activity concentrations. The calculated VT values were used for training a random forest regressor. As input features for the model, we used three late PET frames (60–70, 70–80, and 80–90 min p.i.), the ASL image reflecting perfusion, the voxel coordinates, the lesion mask, and the five plasma activity concentrations. The algorithm was validated with the leave-one-out approach. To estimate the impact of the individual features on the algorithm’s performance, we used Shapley Additive Explanations (SHAP). Having determined that the three late PET frames and the plasma activity concentrations were the most important features, we tested a simplified quantification approach consisting of dividing a late PET frame by a plasma activity concentration. All the combinations of frames/samples were compared by means of concordance correlation coefficient and Bland-Altman plots. ResultsWhen using all the input features, the algorithm predicted VT values with high accuracy (87.8 ± 8.3%) for both lesion and non-lesion voxels. The SHAP values demonstrated high impact of the late PET frames (60–70, 70–80, and 80–90 min p.i.) and plasma activity concentrations on the VT prediction, while the influence of the ASL-derived perfusion, voxel coordinates, and the lesion mask was low. Among all the combinations of the late PET frames and plasma activity concentrations, the 70–80 min p.i. frame divided by the 30 min p.i. plasma sample produced the closest VT estimate in the ischemic lesion. ConclusionReliable TSPO PET quantification is achievable by using a single late PET frame divided by a late blood sample activity concentration.

Development of a minimally invasive simultaneous estimation method for quantifying translocator protein binding with [18F]FEPPA positron emission tomography

BackgroundThe purpose of this study was to assess the feasibility of using a minimally invasive simultaneous estimation method (SIME) to quantify the binding of the 18-kDa translocator protein tracer [18F]FEPPA. Arterial sampling was avoided by extracting an image-derived input function (IDIF) that was metabolite-corrected using venous blood samples. The possibility of reducing scan duration to 90 min from the recommended 2–3 h was investigated by assuming a uniform non-displaceable distribution volume (VND) to simplify the SIME fitting.ResultsSIME was applied to retrospective data from healthy volunteers and was comprised of both high-affinity binders (HABs) and mixed-affinity binders (MABs). Estimates of global VND and regional total distribution volume (VT) from SIME were not significantly different from values obtained using a two-tissue compartment model (2CTM). Regional VT estimates were greater for HABs compared to MABs for both the 2TCM and SIME, while the SIME estimates had lower inter-subject variability (41 ± 17% reduction). Binding potential (BPND) values calculated from regional VT and brain-wide VND estimates were also greater for HABs, and reducing the scan time from 120 to 90 min had no significant effect on BPND. The feasibility of using venous metabolite correction was evaluated in a large animal model involving a simultaneous collection of arterial and venous samples. Strong linear correlations were found between venous and arterial measurements of the blood-to-plasma ratio and the remaining [18F]FEPPA fraction. Lastly, estimates of BPND and the specific distribution volume (i.e., VS = VT − VND) from a separate group of healthy volunteers (90 min scan time, venous-scaled IDIFs) agreed with estimates from the retrospective data for both genotypes.ConclusionsThe results of this study demonstrate that accurate estimates of regional VT, BPND and VS can be obtained by applying SIME to [18F]FEPPA data. Furthermore, the application of SIME enabled the scan time to be reduced to 90 min, and the approach worked well with IDIFs that were scaled and metabolite-corrected using venous blood samples.

Evaluation of [18F]PF-06455943 as a Potential LRRK2 PET Imaging Agent in the Brain of Nonhuman Primates.

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the common causes of inherited Parkinson's disease (PD) and emerged as a causative PD gene. Particularly, LRRK2-Gly2019Ser mutation was reported to alter the early phase of neuronal differentiation, increasing cell death. Selective inhibitors of LRRK2 kinase activity were considered as a promising therapeutic target for PD treatment. However, the development of effective brain-penetrant LRRK2 inhibitors remains challenging. Recently, we have developed a novel positron emission tomography (PET) radioligand for LRRK2 imaging and demonstrated preferable tracer properties in rodents. Herein, we evaluate [18F]PF-06455943 quantification methods in the nonhuman primate (NHP) brain using full kinetic modeling with radiometabolite-corrected arterial blood samples, and homologous blocking with two doses (0.1 and 0.3 mg/kg). Kinetic analysis results demonstrated that a two-tissue compartmental model and a Logan graphical analysis are appropriate for [18F]PF-06455943 PET quantification. In addition, we observed that total distribution volume (VT) values can be reliably estimated with as short as a 30 min scan duration. Homologous blocking studies confirmed the specific binding of [18F]PF-06455943 and revealed that the nonradioactive mass of PF-06455943 achieved 45-55% of VT displacement in the whole brain. This work supports the translation of [18F]PF-06455943 PET imaging for the human brain and target occupancy studies.

Preliminary Assessment of Reference Region Quantification and Reduced Scanning Times for [18F]SynVesT-1 PET in Parkinson's Disease.

Synaptic density in the central nervous system can be measured in vivo using PET with [18F]SynVesT-1. While [18F]SynVesT-1 has been proven to be a powerful radiopharmaceutical for PET imaging of neurodegenerative disorders such as Parkinson's disease (PD), its currently validated acquisition and quantification protocols are invasive and technically challenging in these populations due to the arterial sampling and relatively long scanning times. The objectives of this work were to evaluate a noninvasive (reference tissue) quantification method for [18F]SynVesT-1 in PD patients and to determine the minimum scan time necessary for accurate quantification. [18F]SynVesT-1 PET scans were acquired in 5 patients with PD and 3 healthy control subjects for 120 min with arterial blood sampling. Quantification was performed using the one-tissue compartment model (1TCM) with arterial input function, as well as with the simplified reference tissue model (SRTM) to estimate binding potential (BPND) using centrum semiovale (CS) as a reference region. The SRTM2 method was used with k2' fixed to either a sample average value (0.037 min-1) or a value estimated first through coupled fitting across regions for each participant. Direct SRTM estimation and the Logan reference region graphical method were also evaluated. There were no significant group differences in CS volume, radiotracer uptake, or efflux (ps > 0.47). Each fitting method produced BPND estimates in close agreement with those derived from the 1TCM (subject R2s > 0.98, bias < 10%), with no difference in bias between the control and PD groups. With SRTM2, BPND estimates from truncated scan data as short as 80 min produced values in excellent agreement with the data from the full 120 min scans (bias < 6%). While these are preliminary results from a small sample of patients with PD (n = 5), this work suggests that accurate synaptic density quantification may be performed without blood sampling and with scan time under 90 minutes. If further validated, these simplified procedures for [18F]SynVesT-1 PET quantification can facilitate its application as a clinical research imaging technology and allow for larger study samples and include a broader scope of patients including those with neurodegenerative diseases.

An untrained deep learning method for reconstructing dynamic MR images from accelerated model-based data.

To implement physics-based regularization as a stopping condition in tuning an untrained deep neural network for reconstructing MR images from accelerated data. The ConvDecoder (CD) neural network was trained with a physics-based regularization term incorporating the spoiled gradient echo equation that describes variable-flip angle data. Fully-sampled variable-flip angle k-space data were retrospectively accelerated by factors of R={8, 12, 18, 36} and reconstructed with CD, CD with the proposed regularization (CD + r), locally low-rank (LR) reconstruction, and compressed sensing with L1-wavelet regularization (L1). Final images from CD + r training were evaluated at the "argmin" of the regularization loss; whereas the CD, LR, and L1 reconstructions were chosen optimally based on ground truth data. The performance measures used were the normalized RMS error, the concordance correlation coefficient, and the structural similarity index. The CD + r reconstructions, chosen using the stopping condition, yielded structural similarity indexs that were similar to the CD (p=0.47) and LR structural similarity indexs (p=0.95) across R and that were significantly higher than the L1 structural similarity indexs (p=0.04). The concordance correlation coefficient values for the CD + r T1 maps across all R and subjects were greater than those corresponding to the L1 (p=0.15) and LR (p=0.13) T1 maps, respectively. For R ≥ 12 (≤4.2min scan time), L1 and LR T1 maps exhibit a loss of spatially refined details compared to CD + r. The use of an untrained neural network together with a physics-based regularization loss shows promise as a measure for determining the optimal stopping point in training without relying on fully-sampled ground truth data.

Differential properties of Early vs. Late 18F‐Florbetaben imaging acquisition time frames

AbstractBackground18F‐Florbetaben (FBB) is a PET radioligand approved for determining binary amyloid status. According to the product label, FBB images may be acquired anytime 45‐130 minutes post injection. Protocols vary in the acquisition of FBB with respect to use of Early (50‐70 minutes‐post‐injection) or Late (90‐110 minutes‐post‐injection) frames. Identifying differences between Early and Late acquisitions of FBB data could aid in image interpretation and inform efforts towards harmonization across cohorts. We evaluated inter‐rater agreement of visual reads (VR) and differences in SUVR thresholds to characterize Early vs. Late frames.MethodFifty‐three subjects were studied including 23 patients meeting clinical criteria for amnestic mild cognitive impairment or mild Alzheimer’s disease and 30 cognitively normal controls. FBB images were acquired 50‐110 min post‐injection in 5‐min frames. Images were corrected for subject motion and separated into 50‐70 and 90‐110 min time windows. Three certified readers blind to cognitive status and time window provided a binary VR for each of the 106 data sets. Global standardized uptake value ratios (SUVRs) were calculated using a cerebellar gray matter reference. An ROC‐derived SUVR cut‐off value was determined for each window using a preliminary cohort (n=23) and evaluated in a larger cohort (n = 53).ResultInter‐reader agreement was similar in 50‐70 min and 90‐110 min scans, (Fleiss Kappa= 0.597 and 0.598). SUVRs from 50‐70 min and 90‐110 min scans were highly correlated (r = 0.99, p&lt;0.0001). SUVRs were greater in visually positive than in visually negative scans for both time windows (Fig. 1; p&lt;0.0001). SUVRs were still increasing at 50‐70 min but became but plateaued at 90 min. ROC‐derived SUVR cut‐off values (Fig. 1; SUVR50‐70=1.342, SUVR90‐110=1.524) largely agreed with the majority consensus VR (49/53; 92.5%) across both time frames.ConclusionEarly and Late frame data were highly correlated, and both provided robust quantitative differences between visually positive and negative Ab groups. However, imaging at 90‐110 min provides more stable SUVRs and therefore is preferred for measuring longitudinal change in amyloid burden.

Differential properties of Early vs. Late 18F‐Florbetaben imaging acquisition time frames

AbstractBackground18F‐Florbetaben (FBB) is a PET radioligand approved for determining binary amyloid status. According to the product label, FBB images may be acquired anytime 45‐130 minutes post injection. Protocols vary in the acquisition of FBB with respect to use of Early (50‐70 minutes‐post‐injection) or Late (90‐110 minutes‐post‐injection) frames. Identifying differences between Early and Late acquisitions of FBB data could aid in image interpretation and inform efforts towards harmonization across cohorts. We evaluated inter‐rater agreement of visual reads (VR) and differences in SUVR thresholds to characterize Early vs. Late frames.MethodFifty‐three subjects were studied including 23 patients meeting clinical criteria for amnestic mild cognitive impairment or mild Alzheimer’s disease and 30 cognitively normal controls. FBB images were acquired 50‐110 min post‐injection in 5‐min frames. Images were corrected for subject motion and separated into 50‐70 and 90‐110 min time windows. Three certified readers blind to cognitive status and time window provided a binary VR for each of the 106 data sets. Global standardized uptake value ratios (SUVRs) were calculated using a cerebellar gray matter reference. An ROC‐derived SUVR cut‐off value was determined for each window using a preliminary cohort (n=23) and evaluated in a larger cohort (n = 53).ResultInter‐reader agreement was similar in 50‐70 min and 90‐110 min scans, (Fleiss Kappa= 0.597 and 0.598). SUVRs from 50‐70 min and 90‐110 min scans were highly correlated (r = 0.99, p&lt;0.0001). SUVRs were greater in visually positive than in visually negative scans for both time windows (Fig. 1; p&lt;0.0001). SUVRs were still increasing at 50‐70 min but became but plateaued at 90 min. ROC‐derived SUVR cut‐off values (Fig. 1; SUVR50‐70=1.342, SUVR90‐110=1.524) largely agreed with the majority consensus VR (49/53; 92.5%) across both time frames.ConclusionEarly and Late frame data were highly correlated, and both provided robust quantitative differences between visually positive and negative Ab groups. However, imaging at 90‐110 min provides more stable SUVRs and therefore is preferred for measuring longitudinal change in amyloid burden.

PIB‐PET perfusion and FDG‐PET are highly correlated and similarly associated with cognitive performance

AbstractBackgroundFluorodeoxyglucose PET is a useful measure of neurodegeneration in Alzheimer’s disease and aging. Because glucose metabolism and cerebral blood flow are coupled, PET measures of perfusion also detect neurodegeneration. Dynamic PET data obtained immediately following injection of highly extracted tracers can estimate relative perfusion (R1). We performed this study to examine R1 in relation to FDG PET for detection of AD and relationships to cognition.MethodDynamic Pittsburgh compound B (PIB) PET (0‐90 min) and FDG‐PET (30‐60 min) scans were collected in cognitively normal (CN) participants (N=109, mean age 76.2±6.4 years) and Aβ‐positive patients with MCI or dementia (N=85, mean age 65.1±9.6 years). The Simplified Reference Tissue Model 2 estimated R1 and PIB distribution volume ratios, the latter used to dichotomize CN participants by amyloid status (68 Aβ‐, 41 Aβ+). We used a standard “metaROI” composed of FreeSurfer (Desikan‐Killiany) ‐based ROIs in temporal, parietal and cingulate cortex to quantify R1 and FDG in all participants to compare R1 and FDG in the detection of between‐group differences with a one‐way ANOVA, and classification of participants with logistic regression models. Relationships between R1 or FDG and dementia severity, measured as the CDR sum of boxes, were examined in clinically impaired patients in multiple FreeSurfer‐based regions of interest.ResultR1 and FDG were both significantly lower in patients than in CN groups (R1: F(2,191) = 70.5, p&lt;0.000001; FDG: F(2,191) = 87.9, p&lt;0.000001), which did not differ significantly (Figure 1). FDG and R1 were both able to distinguish between patients and CN participants similarly, with sensitivity and specificity ranging from 80‐86% (Figure 2). R1 and FDG were associated with CDR sum of boxes in a similar set of frontal, temporal, and parietal regions, although FDG associations were stronger and more extensive (Figure 3).ConclusionR1 and FDG perform similarly in differentiating dementia patients and controls. Relationships between FDG/R1 and cognitive performance are similar, although FDG shows more extensive associations. R1 measures obtained from dynamic PIB‐PET scans are useful indicators of neurodegeneration which can substitute for FDG in many situations.

PIB‐PET perfusion and FDG‐PET are highly correlated and similarly associated with cognitive performance

AbstractBackgroundFluorodeoxyglucose PET is a useful measure of neurodegeneration in Alzheimer’s disease and aging. Because glucose metabolism and cerebral blood flow are coupled, PET measures of perfusion also detect neurodegeneration. Dynamic PET data obtained immediately following injection of highly extracted tracers can estimate relative perfusion (R1). We performed this study to examine R1 in relation to FDG PET for detection of AD and relationships to cognition.MethodDynamic Pittsburgh compound B (PIB) PET (0‐90 min) and FDG‐PET (30‐60 min) scans were collected in cognitively normal (CN) participants (N=109, mean age 76.2±6.4 years) and Aβ‐positive patients with MCI or dementia (N=85, mean age 65.1±9.6 years). The Simplified Reference Tissue Model 2 estimated R1 and PIB distribution volume ratios, the latter used to dichotomize CN participants by amyloid status (68 Aβ‐, 41 Aβ+). We used a standard “metaROI” composed of FreeSurfer (Desikan‐Killiany) ‐based ROIs in temporal, parietal and cingulate cortex to quantify R1 and FDG in all participants to compare R1 and FDG in the detection of between‐group differences with a one‐way ANOVA, and classification of participants with logistic regression models. Relationships between R1 or FDG and dementia severity, measured as the CDR sum of boxes, were examined in clinically impaired patients in multiple FreeSurfer‐based regions of interest.ResultR1 and FDG were both significantly lower in patients than in CN groups (R1: F(2,191) = 70.5, p&lt;0.000001; FDG: F(2,191) = 87.9, p&lt;0.000001), which did not differ significantly (Figure 1). FDG and R1 were both able to distinguish between patients and CN participants similarly, with sensitivity and specificity ranging from 80‐86% (Figure 2). R1 and FDG were associated with CDR sum of boxes in a similar set of frontal, temporal, and parietal regions, although FDG associations were stronger and more extensive (Figure 3).ConclusionR1 and FDG perform similarly in differentiating dementia patients and controls. Relationships between FDG/R1 and cognitive performance are similar, although FDG shows more extensive associations. R1 measures obtained from dynamic PIB‐PET scans are useful indicators of neurodegeneration which can substitute for FDG in many situations.

Measuring brain beats: Cardiac-aligned fast functional magnetic resonance imaging signals.

Blood and cerebrospinal fluid (CSF) pulse and flow throughout the brain, driven by the cardiac cycle. These fluid dynamics, which are essential to healthy brain function, are characterized by several noninvasive magnetic resonance imaging (MRI) methods. Recent developments in fast MRI, specifically simultaneous multislice acquisition methods, provide a new opportunity to rapidly and broadly assess cardiac-driven flow, including CSF spaces, surface vessels and parenchymal vessels. We use these techniques to assess blood and CSF flow dynamics in brief (3.5min) scans on a conventional 3T MRI scanner in five subjects. Cardiac pulses are measured with a photoplethysmography (PPG) on the index finger, along with functional MRI (fMRI) signals in the brain. We, retrospectively, align the fMRI signals to the heartbeat. Highly reliable cardiac-gated fMRI temporal signals are observed in CSF and blood on the timescale of one heartbeat (test-retest reliability within subjects R2 > 50%). In blood vessels, a local minimum is observed following systole. In CSF spaces, the ventricles and subarachnoid spaces have a local maximum following systole instead. Slower resting-state scans with slice timing, retrospectively, aligned to the cardiac pulse, reveal similar cardiac-gated responses. The cardiac-gated measurements estimate the amplitude and phase of fMRI pulsations in the CSF relative to those in the arteries, an estimate of the local intracranial impedance. Cardiac aligned fMRI signals can provide new insights about fluid dynamics or diagnostics for diseases where these dynamics are important.

Behavior and welfare impacts of water provision via misting in commercial Pekin ducks.

Ducks will access water to maintain feather condition and exhibit natural water-related behaviors such as wet preening. Providing water to ducks commercially is challenging as it may reduce litter and air quality leading to higher duck mortality or illness. This research aimed to measure the behavioral and welfare impacts of water provision via a misting system for commercial Pekin grower ducks in Victoria, Australia. Seven grower flocks were observed (four misted and three nonmisted in open-sided sheds) during May and November 2021. From 26 until 33 d of age, treatment ducks were provided 1 h of misting with shed curtains closed in both treatment and control sheds. At the start and end of the misting application period, external health and welfare measures were taken directly on the ducks via transect walks throughout each shed and catch-and-inspect observations on a sample of 150 ducks from each shed. Video recordings were also made of the misted and nonmisted ducks for 3 h representing time periods prior to, during, and after the 1-h misting across all sheds for all 8 d of the treatment period. Observations were made of all behavior that ducks exhibited at 10-min scan sample intervals across four cameras per shed, totaling 4,198 scans across the seven sheds. General linear mixed models showed the misting application predominantly had impacts on the patterns of behavioral change across the treatment time periods between the misted and nonmisted ducks rather than increasing or decreasing the overall expression of specific behaviors (interaction terms all P ≤ 0.003). The misted ducks increased drinking, tail wagging, and walking, and reduced preening, rooting litter, sitting, and stretching during misting relative to what they showed prior. The nonmisted ducks showed less sitting and more panting during misting relative to prior. Pearson's Chi-square tests showed some differences between the treatment groups in feather cleanliness on the back and wings (both P < 0.0001), likely resulting from pre-existing differences between sheds in blood from pin feathers. Most welfare indicators showed no positive or negative effect of the misting treatment. These results indicate overhead misting does affect duck behavior to some degree without compromising their welfare, but further research with larger water droplet sizes resulting in greater accumulation of surface water or extended durations of misting may lead to greater effects.

Free-running 3D whole-heart T1 and T2 mapping andcineMRI using low-rank reconstruction withnon-rigid cardiac motion correction.

To introduce non-rigid cardiac motion correction into a novel free-running framework for the simultaneous acquisition of 3D whole-heart myocardial and maps and cine images, enabling a 3-min scan. Data were acquired using a free-running 3D golden-angle radial readout interleaved with inversion recovery and -preparation pulses. After correction for translational respiratory motion, non-rigid cardiac-motion-corrected reconstruction with dictionary-based low-rank compression and patch-based regularization enabled 3D whole-heart and mapping at any given cardiac phase as well as whole-heart cardiac cine imaging. The framework was validated and compared with established methods in 11 healthy subjects. Good quality 3D and maps and cine images were reconstructed for all subjects. Septal values using the proposed approach ( ms) were higher than those from a 2D MOLLI sequence ( ms), which is known to underestimate , while values from the proposed approach ( ms) were in good agreement with those from a 2D GraSE sequence ( ms). The proposed technique provides 3D and maps and cine images with isotropic spatial resolution in a single 3.3-min scan.

5 The Use of Alginate Hydrogel Beads During Pig Transportation

Abstract During marketing, pigs are exposed to multiple stressors, including feed/water withdrawal, physical assertion, and mixing with unfamiliar pigs. These stressors can disrupt the homeostasis of the market pig, that in-turn could result in non-ambulatory-non-injured, non-ambulatory injured pigs or death. The objective of this study was to provide pigs electrolytes and a glucose source in alginate hydrogel beads (AHB) to determine if they could mitigate transportation stressors. A maternal neonatal pheromone was added to the AHB to encourage consumption. Sixty (PIC USA Camborough-22 sow line) market pigs (BW 122.27± 32.72 kg), including barrows and gilts were allocated to two treatment groups, either AHB (n= 30) or control (CON) without AHB (n= 30). Pigs were acclimated to the AHB 72-h prior to transport and fasted 12-h before being loaded on a straight trailer and transported for a total of 4-h. Pig body weights were collected before and after transport and blood samples were collected via jugular venipuncture. Active and inactive postures and drinking behavior were recorded using GoPro Cameras during transport and 24-h post-transport using a DVR in one min scan sample. The study was a complete randomized design with pen as the experimental unit. The AHB did not affect the pigs body weight (P &amp;gt; 0.05). Blood chemistry and blood hematology measures showed treatment by time interactions for PH, PCO2, HCO3, BE, TCO2, TBIL and GLU (P ≤ 0.05). During transport AHB pigs displayed more lying than CON pigs (P &amp;lt; 0.05). After transport AHB pigs sat more (P &amp;lt; 0.05) and tended (P &amp;gt; 0.05) to move more than CON pigs. CON pigs engaged in more drinking than AHB pigs after transport (P &amp;lt; 0.05). In conclusion, AHBs had some positive welfare effects on pig physiology and behavior during and immediately after short transportation and show promise as a tool that could be practically implemented by the industry.

Comparison between a dual-time-window protocol and other simplified protocols for dynamic total-body 18F-FDG PET imaging

PurposeEfforts have been made both to avoid invasive blood sampling and to shorten the scan duration for dynamic positron emission tomography (PET) imaging. A total-body scanner, such as the uEXPLORER PET/CT, can relieve these challenges through the following features: First, the whole-body coverage allows for noninvasive input function from the aortic arteries; second, with a dramatic increase in sensitivity, image quality can still be maintained at a high level even with a shorter scan duration than usual. We implemented a dual-time-window (DTW) protocol for a dynamic total-body 18F-FDG PET scan to obtain multiple kinetic parameters. The DTW protocol was then compared to several other simplified quantification methods for total-body FDG imaging that were proposed for conventional setup.MethodsThe research included 28 patient scans performed on an uEXPLORER PET/CT. By discarding the corresponding data in the middle of the existing full 60-min dynamic scan, the DTW protocol was simulated. Nonlinear fitting was used to estimate the missing data in the interval. The full input function was obtained from 15 subjects using a hybrid approach with a population-based image-derived input function. Quantification was carried out in three areas: the cerebral cortex, muscle, and tumor lesion. Micro- and macro-kinetic parameters for different scan durations were estimated by assuming an irreversible two-tissue compartment model. The visual performance of parametric images and region of interest-based quantification in several parameters were evaluated. Furthermore, simplified quantification methods (DTW, Patlak, fractional uptake ratio [FUR], and standardized uptake value [SUV]) were compared for similarity to the reference net influx rate Ki.ResultsKi and K1 derived from the DTW protocol showed overall good consistency (P < 0.01) with the reference from the 60-min dynamic scan with 10-min early scan and 5-min late scan (Ki correlation: 0.971, 0.990, and 0.990; K1 correlation: 0.820, 0.940, and 0.975 in the cerebral cortex, muscle, and tumor lesion, respectively). Similar correlationss were found for other micro-parameters. The DTW protocol had the lowest bias relative to standard Ki than any of the quantification methods, followed by FUR and Patlak. SUV had the weakest correlation with Ki. The whole-body Ki and K1 images generated by the DTW protocol were consistent with the reference parametric images.ConclusionsUsing the DTW protocol, the dynamic total-body FDG scan time can be reduced to 15 min while obtaining accurate Ki and K1 quantification and acceptable visual performance in parametric images. However, the trade-off between quantification accuracy and protocol implementation feasibility must be considered in practice. We recommend that the DTW protocol be used when the clinical task requires reliable visual assessment or quantifying multiple micro-parameters; FUR with a hybrid input function may be a more feasible approach to quantifying regional metabolic rate with a known lesion position or organs of interest.

JS07.4.A Correspondence of glutamine and glycine imaging based on 7T MRSI to amino acid PET

Abstract Background New approaches for 7 Tesla magnetic resonance spectroscopic imaging (MRSI) allow the simultaneous imaging of multiple neuro-oncological biomarkers with 3-4 mm resolution in clinically feasible measurement times. Specifically, the amino acids glutamine (Gln) and Glycine (Gly), were previously limited to single voxel detection at lower fields. Both could add to our capabilities to resolve heterogeneous tumour metabolism. Purpose To progress the validation of Gln and Gly as neuro-oncological markers by conducting the first comparison to amino acid PET in a cohort of glioma patients. Material and Methods In 24 glioma patients (WHO 2021 classification), we quantitatively compared 7T MRSI (3D, 3.4 mm isotropic resolution, 15 min scan time) and routine PET (FET or MET). Within manual tumour segmentations, we defined hotspot volumes of interest (VOI) for the ratios of total choline (tCho, clinical standard reference), Gln, Gly to total N-acetylaspartate (tNAA) and PET tumour-to-brain ratios (TBR), all with a cut-off threshold of 1.6. For these VOIs, we calculated VOI volumes and median ratios as well as Dice similarity coefficients (DSC) and centre of intensity distance (CoI), between MRSI and PET ratios. Results We found that Gln and Gly ratios to tNAA had a higher correspondence to PET-based amino acid metabolism than tCho. Our resulting median VOI volumes were 19.08±23.10 cm³ for tCho/tNAA, 33.68±24.60 cm³ for Gln/tNAA, and 22.38±18.49 cm³ for Gly/tNAA compared to 24.33±30.46 cm³ for PET, with correlation coefficients &amp;gt;0.5 for all MRSI hotspot values in relation to PET volumes. Median ratios were 0.52±0.13 for tCho/tNAA, 0.61±0.25 for Gln/tNAA, 0.33±0.15 for Gly/tNAA and 2.11±0.42 for PET. The median DSCs to PET amounted to 0.53±0.36 for tCho/tNAA, 0.66±0.40 for Gln/tNAA, and 0.57±0.36 for Gly/tNAA, while the median CoI distances were 0.56±0.43 cm for tCho/tNAA, 0.39±0.22 cm for Gln/tNAA, and 0.45±0.48 cm for Gly/tNAA. Conclusion With this first study that compared high-resolution 3D-MRSI at 7 Tesla to amino acid PET and a quantitative evaluation, we demonstrated that Gln and Gly corresponded better to PET than tCho, which is the main marker used in clinical MR, both within the study and compared to previous literature. Future research is needed to clearly define the benefits of 7T MRSI for neuro-oncology such as the identification of tumour microenvironments or non-invasive determination of molecular-pathologic markers. Gln could be further explored by the application of Gln-based PET tracers to MR-PET. We still see further developments of MRSI methods, such as motion correction or absolute quantification of concentrations instead of ratios, as necessary to obtain such goals.

Probing the New Generation Geodetic Radio Telescopes for FRB Observations

We investigate the possibility of fast radio burst (FRB) observation on new special geodetic 13[Formula: see text]m wideband radio telescopes in Very Large Base Interferometry (VLBI) and single-dish modes. The Crab Pulsar Giant Pulses (GPs) were used as a reference source of FRB. In order to verify our results we use joint simultaneous observations with 32[Formula: see text]m legacy and 13[Formula: see text]m new VLBI Global Observing System (VGOS) radio telescopes of the Quasar VLBI network in the L and S/X frequency bands. The special observation session contains two 10-min scans of Crab Pulsar. We successfully detect a total of 712 pulses with flux density [Formula: see text][Formula: see text]Jy at 1653.5[Formula: see text]MHz on 32-m antenna and 262 pulses with flux density [Formula: see text][Formula: see text]Jy at 2406.3[Formula: see text]MHz on 13-m antenna in Badary observatory. The VLBI fringes were obtained for approximately every third pulse. The energy distribution of detected pulses has a break in the power law fit at [Formula: see text] and [Formula: see text]-values are [Formula: see text]0.2 and [Formula: see text]1.8 for lower and higher energies. A GP with a fluence of the order of 190[Formula: see text][Formula: see text] in L-band was detected and 48[Formula: see text][Formula: see text] in S-band. We found that the peak coincidence of right and left circular polarizations of dedispersed data on a single antenna can provide a maximum detection rate with fixed false probability. It was shown that the best GP detection rate on 13[Formula: see text]m VGOS radio telescope was achieved at Badary observatory with 13 pulses per minute in the S-band.

Cognitive enrichment in a social setting: assessing the use of a novel food maze in sanctuary-housed chimpanzees

Foraging devices are effective enrichment tools for non-human primates, as they provide both cognitive and manipulative stimulation that may enhance these animals’ welfare. We assessed the behavioral effects of a novel tool-based enrichment on 14 chimpanzees (Pan troglodytes) housed at Fundació Mona (Girona, Spain). The device consisted of a vertical maze filled with food rewards, which chimpanzees could extract by using tools. We conducted behavioral observations in two conditions over an approximately 2.5-month period: when the food maze was loaded (12 enrichment days), and when it was empty (12 baseline days). Data were collected using 2-min scan sampling and untimed-event focal sampling during two daily sessions of 80 min each. We expected that the chimpanzees’ interest in the enrichment would decrease over time, but that its use would be linked to an increase in the occurrence of species-typical behaviors, a reduction in negative indicators of welfare, and changes in social behaviors. We found that participation widely varied among subjects, being higher in females and decreasing through time. Furthermore, participation was linked to an increase in tool use and a decrease in inactivity, but also to an increase in aggression-related behaviors. In contrast, participation had no effect on the occurrence of abnormal behaviors, social proximity or affiliation-related behaviors. Finally, we detected an increase in self-directed behaviors only when subjects actively interacted with the device. We conclude that, in future studies, these types of devices should be evaluated for longer periods of time and more attention should be paid to individuals’ preferences and abilities.