Min Scan Research Articles

Automated video analysis of pig activity at pen level highly correlates to human observations of behavioural activities

Automated collection of continuous activity data of pigs can be performed easily using video analysis. In welfare and health research, this technique can be economically advantageous over manual observations. However, the relationship between activity measures by automated video analysis and manually scored behavioural activity has never been established. We correlated automated activity measures through video analysis to ethological scores of pig activity, using off-line video recordings of four pens with grower pigs. Human observations (HO) of different behavioural activities were carried out by 2-min scan sampling during four 30-min sessions on 6 observation days. HO of pig activity was expressed as a mean proportion per session. Automated observations (AO) of pig activity were calculated by the relative number of moving pixels between two consecutive image frames (1 frame/s) and expressed as a mean image activity index per session. The overall correlation between pig activity data from AO and HO was strong and positive (Rs=0.92, P<0.0001). When comparing AO and HO data at session level, the correlation coefficients for the two afternoon sessions were lower. Both static activities and activities involving locomotion had a significant effect on the activity index of AO (P<0.05), but activities that included locomotion had a three times higher effect than static activities. Further validation research is necessary, but it can be concluded that automated video analysis is a promising technique to continuously monitor behavioural activity level of pigs at pen level.

Electroencephalography/functional magnetic resonance imaging responses help predict surgical outcome in focal epilepsy

Simultaneous electroencephalography/functional magnetic resonance imaging (EEG/fMRI) recording can noninvasively map in the whole brain the hemodynamic response following an interictal epileptic discharge. EEG/fMRI is gaining interest as a presurgical evaluation tool. This study aims to determine how hemodynamic responses related to epileptic activity can help predict surgical outcome in patients considered for epilepsy surgery. Thirty-five consecutive patients with focal epilepsy who had significant hemodynamic responses and eventually surgical resection, were studied. The statistical map of hemodynamic responses were generated and co-registered to postoperative anatomic imaging. Patients were classified into four groups defined by the relative relationship between the location of the maximum hemodynamic response and the resection: group 1, fully concordant; group 2, partially concordant; group 3, partially discordant; and group 4, fully discordant. These findings were correlated with surgical outcome with at least 12-month follow-up. Ten patients in group 1 had the maximum t value (t-max) inside the resection; nine in group 2 had the t-max outside but close to the resection and the cluster with t-max overlapped the resection; five in group 3 had the t-max remote from resection, but with another less significant cluster in the resection; and 11 in group 4 had no response in the resection. The degree of concordance correlated largely with surgical outcome: a good surgical outcome (Engel's class I) was found in 7 of 10 patients of group 1, 4 of 9 of group 2, 3 of 5 of group 3, and only 1 of 11 of group 4. These results indicate that the partially concordant and partially discordant groups are best considered as inconclusive. In contrast, in the fully concordant and fully discordant groups, the sensitivity, specificity, positive predictive value, and negative predictive value were high, 87.5%, 76.9%, 70%, and 90.9%, respectively. This study demonstrates that hemodynamic responses related to epileptic activity can help delineate the epileptogenic region. Full concordance between maximum response and surgical resection is indicative of seizure freedom, whereas a resection leaving the maximum response intact is likely to lead to a poor outcome. EEG/fMRI is noninvasive but is limited to patients in whom interictal epileptic discharges can be recorded during the 60-90 min scan.

Ultrashort echo time (UTE) magnetic resonance imaging of the short T2 components in white matter of the brain using a clinical 3T scanner

White matter of the brain contains a majority of long T2 components as well as a minority of short T2 components. These are not detectable using clinical magnetic resonance imaging (MRI) sequences with conventional echo times (TEs). In this study we used ultrashort echo time (UTE) sequences to investigate the ultrashort T2 components in white matter of the brain and quantify their T2*s and relative proton densities (RPDs) (relative to water with a proton density of 100%) using a clinical whole body 3T scanner. An adiabatic inversion recovery prepared dual echo UTE (IR-dUTE) sequence was used for morphological imaging of the ultrashort T2 components in white matter. IR-dUTE acquisitions at a constant TR of 1000ms and a series of TIs were performed to determine the optimal TI which corresponded to the minimum signal to noise ratio (SNR) in white matter of the brain on the second echo image. T2*s of the ultrashort T2 components were quantified using mono-exponential decay fitting of the IR-dUTE signal at a series of TEs. RPD was quantified by comparing IR-dUTE signal of the ultrashort T2 components with that of a rubber phantom. Nine healthy volunteers were studied. The IR-dUTE sequence provided excellent image contrast for the ultrashort T2 components in white matter of the brain with a mean signal to noise ratio of 18.7±3.7 and a contrast to noise ratio of 14.6±2.4 between the ultrashort T2 white matter and gray matter in a 4.4min scan time with a nominal voxel size of 1.25×1.25×5.0mm3. On average a T2* value of 0.42±0.08ms and a RPD of 4.05±0.88% were demonstrated for the ultrashort T2 components in white matter of the brain of healthy volunteers at 3T.

Large-Scale Brain Networks in the Awake, Truly Resting Marmoset Monkey

Resting-state functional MRI is a powerful tool that is increasingly used as a noninvasive method for investigating whole-brain circuitry and holds great potential as a possible diagnostic for disease. Despite this potential, few resting-state studies have used animal models (of which nonhuman primates represent our best opportunity of understanding complex human neuropsychiatric disease), and no work has characterized networks in awake, truly resting animals. Here we present results from a small New World monkey that allows for the characterization of resting-state networks in the awake state. Six adult common marmosets (Callithrix jacchus) were acclimated to light, comfortable restraint using individualized helmets. Following behavioral training, resting BOLD data were acquired during eight consecutive 10 min scans for each conscious subject. Group independent component analysis revealed 12 brain networks that overlap substantially with known anatomically constrained circuits seen in the awake human. Specifically, we found eight sensory and "lower-order" networks (four visual, two somatomotor, one cerebellar, and one caudate-putamen network), and four "higher-order" association networks (one default mode-like network, one orbitofrontal, one frontopolar, and one network resembling the human salience network). In addition to their functional relevance, these network patterns bear great correspondence to those previously described in awake humans. This first-of-its-kind report in an awake New World nonhuman primate provides a platform for mechanistic neurobiological examination for existing disease models established in the marmoset.

MAGNETIC RESONANCE IMAGING CONTRAST ENHANCEMENT OF EXTRA‐OCULAR MUSCLES IN DOGS WITH NO CLINICAL EVIDENCE OF ORBITAL DISEASE

Enhancement of extra-ocular muscles has been reported in cases of orbital pathology in both veterinary and medical magnetic resonance imaging. We have also observed this finding in the absence of orbital disease. The purpose of this retrospective study was to describe extra-ocular muscle contrast enhancement characteristics in a group of dogs with no known orbital disease. Magnetic resonance images (MRI) from dogs with no clinical evidence of orbital disease and a reportedly normal MRI study were retrieved and reviewed. Contrast enhancement percentages of the medial, lateral, ventral, and dorsal rectus muscles were calculated based on signal-to-noise ratios that were in turn determined from hand-traced regions of interest in precontrast, immediate postcontrast and 10-min postcontrast scans. Comparison measurements were made in the pterygoid muscle. Contrast enhancement of the extra-ocular muscles was observed in all patients (median contrast enhancement percentage 45.0%) and was greater than that of pterygoid muscle (median contrast enhancement percentage 22.7%). Enhancement of the extra-ocular muscles persisted 10 min after contrast administration (median contrast enhancement percentage 43.4%). Findings indicated that MRI contrast enhancement of extra-ocular muscles is likely normal in dogs.

Quantification of 18F-JNJ-42259152, a Novel Phosphodiesterase 10A PET Tracer: Kinetic Modeling and Test–Retest Study in Human Brain

Phosphodiesterase 10A (PDE10A) plays a central role in striatal signaling and is implicated in several neuropsychiatric disorders, such as movement disorders and schizophrenia. We performed initial brain kinetic modeling of the novel PDE10A tracer (18)F-JNJ-42259152 (2-[[4-[1-(2-(18)F-fluoroethyl)-4-(4-pyridinyl)-1H-pyrazol-3-yl]phenoxy]methyl]-3,5-dimethyl-pyridine) and studied test-retest reproducibility in healthy volunteers. Twelve healthy volunteers (5 men, 7 women; age range, 42-77 y) were scanned dynamically up to 135 min after bolus injection of 172.5 ± 10.3 MBq of (18)F-JNJ42259152. Four volunteers (2 men, 2 women) underwent retest scanning, with a mean interscan interval of 37 d. Input functions and tracer parent fractions were determined using arterial sampling and high-performance liquid chromatography analysis. Volumes of interest for the putamen, caudate nucleus, ventral striatum, substantia nigra, thalamus, frontal cortex, and cerebellum were delineated using individual volumetric T1 MR imaging scans. One-tissue (1T) and 2-tissue (2T) models were evaluated to calculate total distribution volume (VT). Simplified models were also tested to calculate binding potential (BPND), including the simplified reference tissue model (SRTM) and multilinear reference tissue model, using the frontal cortex as the optimal reference tissue. The stability of VT and BPND was assessed down to a 60-min scan time. The average intact tracer half-life in blood was 90 min. The 2T model VT values for the putamen, caudate nucleus, ventral striatum, substantia nigra, thalamus, frontal cortex, and cerebellum were 1.54 ± 0.37, 0.90 ± 0.24, 0.64 ± 0.18, 0.42 ± 0.09, 0.35 ± 0.09, 0.30 ± 0.07, and 0.36 ± 0.12, respectively. The 1T model provided significantly lower VT values, which were well correlated to the 2T VT. SRTM BPND values referenced to the frontal cortex were 3.45 ± 0.43, 1.78 ± 0.35, 1.10 ± 0.31, and 0.44 ± 0.09 for the respective target regions putamen, caudate nucleus, ventral striatum, and substantia nigra, with similar values for the multilinear reference tissue model. Good correlations were found for the target regions putamen, caudate nucleus, ventral striatum, and substantia nigra between the 2T-compartment model BPND and the SRTM BPND (r = 0.57, 0.82, 0.70, and 0.64, respectively). SRTM BPND using a 90- and 60-min acquisition interval showed low bias. Test-retest variability was 5%-19% for 2T VT and 5%-12% for BPND SRTM. Kinetic modeling of (18)F-JNJ-42259152 shows that PDE10A activity can be reliably quantified and simplified using a reference tissue model with the frontal cortex as reference and a 60-min acquisition period.

Longitudinal Amyloid Imaging in Mouse Brain with 11C-PIB: Comparison of APP23, Tg2576, and APPswe-PS1dE9 Mouse Models of Alzheimer Disease

Follow-up of β-amyloid (Aβ) deposition in transgenic mouse models of Alzheimer disease (AD) would be a valuable translational tool in the preclinical evaluation of potential antiamyloid therapies. This study aimed to evaluate the ability of the clinically used PET tracer (11)C-Pittsburgh compound B ((11)C-PIB) to detect changes over time in Aβ deposition in the brains of living mice representing the APP23, Tg2576, and APP(swe)-PS1(dE9) transgenic mouse models of AD. Mice from each transgenic strain were imaged with 60-min dynamic PET scans at 7-9, 12, 15, and 18-22 mo of age. Regional (11)C-PIB retention was quantitated as distribution volume ratios using Logan graphical analysis with cerebellar reference input, as radioactivity uptake ratios between the frontal cortex (FC) and the cerebellum (CB) during the 60-min scan, and as bound-to-free ratios in the late washout phase (40-60 min). Ex vivo autoradiography experiments were performed after the final imaging session to validate (11)C-PIB binding to Aβ deposits. Additionally, the presence of Aβ deposits was evaluated in vitro using staining with thioflavin-S and Aβ1-40, Aβ1-16, and AβN3(pE) immunohistochemistry. Neocortical (11)C-PIB retention was markedly increased in old APP23 mice with large thioflavin-S-positive Aβ deposits. At 12 mo, the Logan distribution volume ratio for the FC was 1.03 and 0.93 (n = 2), increasing to 1.38 ± 0.03 (n = 3) and 1.34 (n = 1) at 18 and 21 mo of age, respectively. An increase was also observed in bound-to-free ratios for the FC between young (7- to 12-mo-old) and old (15- to 22-mo-old) APP23 mice. Binding of (11)C-PIB to Aβ-rich cortical regions was also evident in ex vivo autoradiograms of APP23 brain sections. In contrast, no increases in (11)C-PIB retention were observed in aging Tg2576 or APP(swe)-PS1(dE9) mice in vivo, although in the latter, extensive Aβ deposition was already observed at 9 mo of age with immunohistochemistry. The results suggest that (11)C-PIB binding to Aβ deposits in transgenic mouse brain is highly dependent on the AD model and the structure of its Aβ plaques. Longitudinal in vivo (11)C-PIB uptake studies are possible in APP23 mice.

Exploratory analyses of regional human brain distribution of the PET tau tracer F18-labeled T807 (AV-1541) in subjects with normal cognitive function or cognitive impairment thought to be due to Alzheimer's disease

Recently, [F-18]-T807 was reported as having high affinity and selectivity to PHF-tau in brain sections from Alzheimer's disease patients (Xia et al, 2013). Chien et al, (2012) described initial imaging results in 6 subjects. We now have extended these initial observations. Ten subjects (6 F / 4 M; mean age 69) were recruited that were either cognitively normal (n=3) or had cognitive impairment of varying degrees thought to be due to Alzheimers Disease (AD; n=7). Mini-Mental State Exam (MMSE) scores ranged from 29 to 30 (mean = 29.7) and 7 to 29 (mean = 20.3), respectively. PET scanning consisted of dynamic (0–60 min) and static (80–100 min) scans after injection of approximately 10 mCi (370 MBq) iv [F-18]-T807 (AV-1541). Static PET scans were visually reviewed and also processed quantitatively by spatial normalization to MNI space and the AAL atlas. Cerebellum uptake was used as a visual and quantitative reference region for SUVr. Pearson's correlations examined possible relationships between [F-18]-T807 uptake and MMSE. Visually, the 3 cognitively normal subjects showed cortical uptake restricted to mesial temporal lobe regions only. In contrast, 6/7 of the cognitively impaired subjects had multiple focal areas of increased uptake (typically parts of lateral and medial temporal, lateral and medial parietal, and occipital lobes). The entire set of AAL regions for all subjects had SUVr range of 0.69 to 2.24. Intra-subject correlations of MMSE scores to mean and peak SUVr values were -0.75 (p=0.011) and -0.76 (p=0.011), respectively. Uptake in some regions, and combinations of regions, showed variably higher correlations to MMSE, up to r = -0.90. The observed patterns of regional [F-18]-T807 uptake are consistent with previous observations at autopsy in AD patients (levels and extent of tau deposits and neurofibrillary tangles correlating with cognitive decline) and non-affected elderly (mesial temporal lobe deposits in Braak stages I-II), and support [F-18]-T807 as a suitable PET tracer for quantification of PHF-tau in human brain. Further studies are important to replicate these results, to better understand the relationship of specific PET brain regions to cognitive function and to comprehensively study tau deposition across the lifespan.

Design of a Four-Channel Surface Receiver Coil Array Without Preamplifiers for the Decoupling Between Elements: Validation for High-Resolution Rat Knee MR Imaging

In magnetic resonance imaging, multichannel coil arrays are increasingly being used to improve signal-to-noise ratio in order to increase spatial and/or temporal image resolution. A recent decoupling technique allows conception of two-channel surface transceiver coil arrays. This technique, based on a common conductor, does not require an additional preamplifier for the decoupling between elements. In this case, the coil array loops are directly connected to the independent transmit/receive switches and preamplifiers of the MR system. Using this common conductor decoupling technique, a topology of a four-channel coil array is developed and described in this paper. A four-channel surface receiver coil array is designed to perform the simultaneous acquisition of both rat knee joints at 7 T. Without the use of additional preamplifiers, a good decoupling between channels is obtained and very high spatial resolution 3-D images with a voxel size of $49\times 49\times 98~\mu{\rm m}^{3}$ is achieved in 1 h 22 min scan time. Acquisitions allow the quantification of cartilage morphological parameters such as thickness and volume.

TU‐G‐134‐03: MR‐Only‐Based Generation of Electron Density Maps and Digitally Reconstructed Radiographs of the Pelvis

Purpose: To generate electron density (ED) maps and digitally reconstructed radiographs (DRRs) of the pelvis based only on magnetic resonance imaging (MRI). Methods: A conventional 3D fast‐field dual‐echo sequence was used to acquire image data of 8 healthy subjects with a Philips 3.0T Ingenia TX system in approximately 1:50 min scan time per volunteer. Dixon reconstruction of the nearly out‐of‐phase (echo 1) and in‐phase images (echo 2) allowed for water and fat classification. A bone‐enhanced image was generated by automatically thresholding the noise level of the in‐phase image with subsequent background removal. ED maps were then produced by assigning known bulk electron densities to the classified bone and tissue fractions. A bone probability atlas derived from CT data was registered to the ED map in order to filter out misclassified voxels. Finally, DRRs were reconstructed from bone‐enhanced images as well as from ED maps. Results: The proposed MRI sequence with subsequent Dixon reconstruction and probabilistic filtering makes it possible to classify cortical bone, soft tissue and adipose tissue in the pelvis and yields ED maps and corresponding DRRs. Bowel content was misclassified as cortical bone or air and compromised the segmentation in some slices as well as in the DRRs. Automatic probabilistic atlas filtering can significantly reduce artifacts induced by bowel content without affecting pelvic bone structures markedly. In total, the artifact/bone fraction dropped from 1.7 before filtering to 0.2 after filtering. The average reduction of artifact volume is 87%, and the average bone preservation is 99%. Remaining artifacts are spatially close to the true bone in areas of positive bone probability. Conclusion: This study demonstrated the feasibility of generating realistic ED maps of the pelvis by using MRI only. The method has the potential to become an essential component of emerging applications such as MR‐only‐based radiation therapy planning. All authors have the following relevant financial interest or relationship to disclose with regard to the subject matter of this presentation: Company name: Philips Research; Type of relationship: Employee

Safety of retained microcatheters: an evaluation of radiofrequency heating in endovascular microcatheters with nitinol, tungsten, and polyetheretherketone braiding at 1.5 T and 3 T

BackgroundThe use of ethylene-vinyl alcohol copolymer for liquid embolization of cranial vascular lesions has resulted in microcatheter fragments entrapped in patients following endovascular procedures. Undergoing subsequent diagnostic MRI examinations poses...

FEASIBILITY FOR MAPPING CARTILAGE T1 RELAXATION TIMES IN THE DISTAL METACARPUS3/METATARSUS3 OF THOROUGHBRED RACEHORSES USING DELAYED GADOLINIUM‐ENHANCED MAGNETIC RESONANCE IMAGING OF CARTILAGE (dGEMRIC): NORMAL CADAVER STUDY

Osteoarthritis of the metacarpo/metatarsophalangeal joints is one of the major causes of poor performance in horses. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) may be a useful technique for noninvasively quantifying articular cartilage damage in horses. The purpose of this study was to describe dGEMRIC characteristics of the distal metacarpus3/metatarsus3 (Mc3/Mt3) articular cartilage in 20 cadaver specimens collected from normal Thoroughbred horses. For each specimen, T1 relaxation time was measured from scans acquired precontrast and at 30, 60, 120, and 180 min post intraarticular injection of Gd-DTPA(2-) (dGEMRIC series). For each scan, T1 relaxation times were calculated using five regions of interest (sites 1-5) in the cartilage. For all sites, a significant decrease in T1 relaxation times occurred between precontrast scans and 30, 60, 120, and 180 min scans of the dGEMRIC series (P < 0.0001). A significant increase in T1 relaxation times occurred between 60 and 180 min and between 120 and 180 min post Gd injection for all sites. For sites 1-4, a significant increase in T1 relaxation time occurred between 30 and 180 min postinjection (P < 0.05). Sites 1-5 differed significantly among one another for all times (P < 0.0001). Findings from this cadaver study indicated that dGEMRIC using intraarticular Gd-DTPA(2-) is a feasible technique for measuring and mapping changes in T1 relaxation times in equine metacarpo/metatarsophalangeal joint cartilage. Optimal times for postcontrast scans were 60-120 min. Future studies are needed to determine whether these findings are reproducible in live horses.

4:02 PM Abstract No. 172 - Tungsten and nitinol braided endovascular catheters: an evaluation of heating in 1.5 t

Purpose Interventional MRI offers the ability to provide soft tissue contrast and functional information in the absence of ionizing radiation. However, performing endovascular procedures in MRI raises safety concerns due to heating from the metallic braid incorporated into catheters. Heating in tungsten and nitinol braided catheters was assessed in an in vitro model simulating a patient undergoing a scan at specific absorption rate (SAR) level of 4 W/kg. Materials and Methods Heating adjacent to the catheters was assessed with fluoroptic temperature probes placed at the device tip, 5cm, 10cm, and 20cm proximal to the tip in a polyacrylamide gel in the head portion of a phantom. A 2.8F tungsten braided catheter (Terumo Progreat, Somerset, NJ) and a 1.9F nitinol braided catheter (eV3 Echelon, Irvine, CA) were serially embedded in a laterally offset conformation. A 5F stainless steel braided catheter (Cook Beacon Tip Torcon Advantage, Bloomington, IN) was used as a positive control and a temperature sensor was placed in background gel, well away from devices. Endovascular devices were immersed at 98cm and exposed to 2-min of scanning followed by 8-min without scanning. The immersed length was shortened by 5cm and this cycle was repeated until the immersed length was 63cm. MR scanning was based on modified fast spin echo imaging on a 1.5T scanner. Results The tungsten braided catheter did not show heating. The maximal heating for the nitinol braided catheter occurred at 20cm proximal to the tip at an immersed length of 93cm. The maximal initial rate of heating was 4.00°C/min and the maximal temperature rise during a 2-min scan was 2.32°C. Heating varied along the catheter, with the most heating at 10cm and 20cm proximal to the tip. The maximal temperature rise during a 2-min scan was 0.33°C for the background and 2.65°C for the positive control. Conclusion The study provides information on the magnitude of focal heating induced in a head simulating a “worst-case” scenario of a patient undergoing a neurovascular procedure. Nitinol displayed substantial heating when compared to the tungsten device. This tungsten braided catheter showed potential safe use in interventional MRI without substantial SAR restrictions.

Seasonal variation of the lying and standing behavior indexes of dairy cattle at different daily time periods in free‐stall housing

The lying and standing behavior of dairy cattle reveal whether dairy cattle housing is appropriate to cow comfort. Lying and standing behavior indexes, such as cow comfort index (CCI), cow stress index (CSI) and stall usage index (SUI) are often used as an indication of animal welfare. This study was performed to determine the seasonal and hourly variation of cow behavioral indexes at different daily time periods (DTP) and evaluate appropriate DTP better representing daily behavioral activity of dairy cattle in free-stall housing (FHS) in Konya, Turkey. Animal behaviors were videotaped for a total of 24 days (576 h) over four seasons in a FHS at a commercial dairy farm from November 2007 to March 2009 using continuous video data (24 h per day). The behaviors of cows in the barn were evaluated using 60-min scan sampling. All phenotypes were evaluated on an hourly basis during the experimental period. The results show how these indexes can be accurately evaluated by analyzing video recordings taken on DTP between 08.00-15.00 and 19.00-24.00 hours for autumn and summer and 10.00-12.00 and 20.00-22.00 hours for spring, instead of continuous observation (r > 0.93, P < 0.01). Consequently, the evaluated method provides saving time and labor to accurately analyze cow behavior instead of observations over a long time.

Sodium quantification in the spinal cord at 3T

Sodium channels are involved in neuronal function and therefore methods to assess tissue sodium concentration in vivo are exceptionally appealing. Recently there has been a renewed interest for brain sodium magnetic resonance imaging (MRI), thanks to higher magnetic field strength scanners. However, sodium measures in the spinal cord are lacking due to major technical challenges. Here we propose for the first time a clinically feasible non-invasive method for quantifying sodium in the spine using magnetic resonance spectroscopy. Sodium spectra from the cervical cord were collected using image selected in vivo spectroscopy (∼14 min scan time) and quantified using a reference phantom. The sodium magnetic resonance spectroscopy measures provided in vivo concentration estimates of 31.2±2.4 mM. Repeat scans showed good reproducibility with a coefficient of variation of <6%. Proposed here for the first time is a fast non-invasive technique to quantify total sodium in the spinal cord in vivo. This newly proposed technique has a great potential for translation into clinic, thanks to its simplicity.

Quantitative PET Imaging Detects Early Metabolic Remodeling in a Mouse Model of Pressure-Overload Left Ventricular Hypertrophy In Vivo

We proposed that metabolic remodeling in the form of increased uptake of the myocardial glucose analog (18)F-FDG precedes and triggers the onset of severe contractile dysfunction in pressure-overload left ventricular hypertrophy in vivo. To test this hypothesis, we used a mouse model of transverse aortic constriction (TAC) together with PET and assessed serial changes in cardiac metabolism and function over 7 d. Scans of 16 C57BL/6 male mice were obtained using a small-animal PET device under sevoflurane anesthesia. A 10-min transmission scan was followed by a 60-min dynamic (18)F-FDG PET scan with cardiac and respiratory gating. Blood glucose levels were measured before and after the emission scan. TAC and sham surgeries were performed after baseline imaging. Osmotic mini pumps containing either propranolol (5 mg/kg/d) or vehicle alone were implanted subcutaneously at the end of surgery. Subsequent scans were taken at days 1 and 7 after surgery. A compartment model, in which the blood input function with spillover and partial-volume corrections and the metabolic rate constants in a 3-compartment model are simultaneously estimated, was used to determine the net myocardial (18)F-FDG influx constant, Ki. The rate of myocardial glucose utilization, rMGU, was also computed. Estimations of the ejection fractions were based on the high-resolution gated PET images. Mice undergoing TAC surgery exhibited an increase in the Ki (580%) and glucose utilization the day after surgery, indicating early adaptive response. On day 7, the ejection fraction had decreased by 24%, indicating a maladaptive response. Average Ki increases were not linearly associated with increases in rMGU. Ki exceeded rMGU by 29% in the TAC mice. TAC mice treated with propranolol attenuated the rate of (18)F-FDG uptake, diminished mismatch between Ki and rMGU (9%), and rescued cardiac function. Metabolic maladaptation precedes the onset of severe contractile dysfunction. Both are prevented by treatment with propranolol. The early detection of metabolic remodeling may offer a metabolic target for modulation of hypertrophy.

Comparison of Myocardial Perfusion Imaging Between the New High-Speed Gamma Camera and the Standard Anger Camera

Cadmium-zinc-telluride (CZT) solid-state detectors have been recently introduced into the field of myocardial perfusion imaging. The aim of this study was to prospectively compare the diagnostic performance of the CZT high-speed gamma camera (Discovery NM 530c) with that of the standard 3-head gamma camera in the same group of patients. The study group consisted of 150 consecutive patients who underwent a 1-day stress-rest (99m)Tc-sestamibi or tetrofosmin imaging protocol. Image acquisition was performed first on a standard gamma camera with a 15-min scan time each for stress and for rest. All scans were immediately repeated on a CZT camera with a 5-min scan time for stress and a 3-min scan time for rest, using list mode. The correlations between the CZT camera and the standard camera for perfusion and function analyses were strong within narrow Bland-Altman limits of agreement. Using list mode analysis, image quality for stress was rated as good or excellent in 97% of the 3-min scans, and in 100% of the ≥4-min scans. For CZT scans at rest, similarly, image quality was rated as good or excellent in 94% of the 1-min scans, and in 100% of the ≥2-min scans. The novel CZT camera provides excellent image quality, which is equivalent to standard myocardial single-photon emission computed tomography, despite a short scan time of less than half of the standard time.

Progesterone administration reduces the behavioural and physiological responses of ewes to abrupt weaning of lambs

Abrupt weaning, a usual management in sheep productive systems, may provoke behavioural and physiological responses indicative of stress in ewes and lambs. Progesterone (P4) has anxiolytic and sedative effects through the union of its metabolites that contain 3α-hydroxyl group to the γ-aminobutyricacidA receptor. Our first aim was to determine whether P4 administration reduces the behavioural and physiological responses of ewes to abrupt weaning of lambs. A complementary aim was to determine whether P4 treatment affects the milk yield and composition of ewes, and the BW of their lambs. In experiment 1, seven ewes received P4 treatment for 32 days (group E1-P4), and eight ewes remained as an untreated control group (group E1-C). BW of the lambs was recorded during P4 treatment. Lambs were weaned at 59 days (Day 0 = weaning). The main behaviours of the ewes before and after weaning were recorded using 10 min scan sampling. The ewes’ serum total protein, albumin and globulin concentrations were measured before and after weaning of the lambs. In experiment 2, milk yield and composition were determined in two different groups of six ewes treated with P4 (group E2-P4) for 16 days and in five untreated controls (group E2-C). The BW of lambs increased with time (P = 0.001) in both groups and did not differ. The percentage of observations in which the ewes were seen pacing on Day 0 was greater in the E1-C group than in the E1-P4 group (P = 0.0007). Similarly, the percentage of observations in which the ewes were recorded vocalizing on Day 0 was greater in the E1-C group than in the E1-P4 group (P = 0.04). The percentage of observations in which E1-C ewes were recorded lying did not change from Days 0 to 1; however, it increased in E1-P4 ewes. Total serum protein concentration did not change in E1-P4 ewes from Days 0 to 3, although a decrease was seen in E1-C ewes (P = 0.04). Serum globulin concentration was greater in E1-P4 ewes on Day 3 than in E1-C ewes (P = 0.0008). In experiment 2, there were no differences between E2-P4 and E2-C ewes in terms of milk yield, protein, fat and lactose content. Progesterone administration reduced the behavioural and physiological responses of ewes to abrupt weaning of lambs, and this effect was not mediated by changes in milk yield and composition, or by lambs’ BW.

Hourly and seasonal variations in the area preferences of dairy cows in freestall housing

Barn designs that promote animal comfort and that reflect preferences of dairy cattle play an important role in increasing animal production. This study was performed in freestall barn housing in Konya (Turkey) to determine the hourly and seasonal variation occurring in the barn area preferences of dairy cows. Behaviors of dairy cows were observed in a freestall barn at a commercial dairy farm from 2006 to 2007 using continuous video data (24h per d). The behaviors of the cows in the barn were videotaped for a total of 40d (960h) over 4 seasons (10d for each season) using a 60-min scan sampling technique. The study design included the hourly and seasonal rates of usage of 5 different parts of the barn area. In addition, temperature and humidity were measured on an hourly basis. The values of the cow comfort index, cow stress index, and stall usage index (SUI) were calculated. All behavioral phenotypes were analyzed with a factorial experimental design. The relationship between the barn area preferences of the dairy cattle and the climatic data for the barn area was significant. The open area (a courtyard) was used at a higher rate by dairy cattle for resting, standing, and walking. In addition, the courtyard area was preferred to the freestalls for resting or lying. The rates of usage of the courtyard during autumn, winter, spring, and summer were 39.0, 20, 66.1, and 52.2%, respectively. The usage rates of the stalls for these seasons were 22.5, 35.7, 4.6, and 8.6%, respectively. The cow comfort index values for autumn, winter, spring, and summer were 0.19, 0.29, 0.03, and 0.05, respectively. The cow stress index values for these seasons were 0.27, 0.29, 0.23, and 0.22, respectively. The qualities and size of the barn areas should allow comfortable movement of the animals. And, it is very important that new barn designs incorporate area preferences and the comfort of the cattle rather than high-cost investments.

Locomotion behavior of cao vit gibbon (Nomascus nasutus) living in karst forest in Bangliang Nature Reserve, Guangxi, China

The cao vit gibbon is a critically endangered species. Only approximately 110 individuals remain in degraded karst forest along the China-Vietnam border. Karst forest is unusual gibbon habitat. Currently, the canopy height of cao vit gibbon habitat is approximately 10 m. Research on the locomotor behavior of gibbons living in this particular forest type might provide important insight into locomotor stability and variability of gibbons. We used 5 min scan samples to record the locomotion mode, support use and canopy strata of gibbons in 3 groups for 2096 h between January 2008 and December 2009. Although cao vit gibbon habitat has a lower canopy in comparison to that of other forests inhabited by gibbons, cao vit gibbons displayed a similar overall locomotor pattern to other gibbon species (Symphalangus syndactylus, Hylobates lar and Hylobates agilis) in which brachiation dominate their locomotor behavior. Cao vit gibbons spent most of their time travelling on inclined branches (2-10 cm) in the middle stratum through the forest canopy. Adult females appear to more often employ safer modes of locomotion (bridging more often and brachiation less), while adult males choose riskier modes (leaping more and climbing less). As gibbons increased in body weight, as they grew from infant to adult, they tended to use larger supports. This research documented that locomotor behavior in Hylobatidae is strongly determined by anatomical characters, but cao vit gibbons also show the ability to use various supports, enabling them to survive in karst forest.