Dystocia as a prolonged stage II parturition (>30 min) was associated with a higher risk of complications. The hypothesis of the study was that any type of dystocia could affect the foal's health, even when the stage II was <30 min. Clinical reports on 222 Standardbred mares and their foals hospitalized at the Veterinary Teaching Hospital of the University of Bologna from 2004 to 2020 were reviewed. Mares were divided into the Eutocia Group (165, eutocic delivery) and the Dystocia Group (57, dystocic delivery). The incidence of dystocia was 4.9%. Stage II was longer in the Dystocia Group (median 20 min) than in the Eutocia Group (median 12 min). All occurrences of dystocia were retrospectively classified into three categories of severity: mild, moderate and severe dystocia. The occurrence of postpartum complications in mares and neonatal diseases and failure of passive transfer of immunity in foals was higher in the Dystocia Group. Foal venous lactatemia and serum creatine kinase were significantly higher in the Dystocia Group (median 3.9 mmol/L; 262 UI/L respectively) than in the Eutocia Group (median 3.1 mmol/L; 187 UI/L respectively). The APGAR score was lower in the Dystocia Group (median 8) than in the Eutocia Group (median 10) and significantly lower in severe dystocia (median 3). The duration of stage II should not be considered the only parameter of dystocia in mares: even a rapid resolution of dystocia could pose health risks to the foal and the mare.
The Animals - Retrospective 2004
Canine mast cell tumors (MCTs) are the most common cutaneous neoplasm in the dog. It has been suggested that MCT in certain locations may behave in a more biologically aggressive fashion than MCTs located in others; however, no published data are available for MCTs of canine pinnae treated with surgical excision. A retrospective study of 28 animals with surgical excision of MCTs of pinnae was completed with a medical record review and follow-up questionnaire to the operating veterinarian. The effect of tumor grade, clean or dirty excision, cartilage penetration, and mitotic index (MI) on local recurrence and survival time (ST) was evaluated. There was local recurrence in one dog with a grade 2 MCT and in seven of eight dogs with grade 3 MCTs. The median ST of animals with grade 1 and 2 MCTs was not reached, whereas the median ST of animals with grade 3 MCTs was 10 mo. There was no statistical association between histologically clean and dirty margins and either local recurrence or ST. A prolonged disease free interval without local recurrence may be achieved with local excision of grade 1 and 2 MCTs. Animals with grade 3 MCTs had a uniformly poor outcome with short times to local recurrence and death.
The most common clinical signs observed were inappetence (41.3%), lethargy/depression (35.6%), vomiting (32.4%), fever (18.5%), paleness (8.2%), and epistaxis (6.6%) (Table-3). In other studies, lethargy, epistaxis, apathy, anorexia, pale mucous membrane, lymphadenopathy, splenomegaly, and uveitis [30,31] were also observed. However, fever was not frequently observed by Inokuma et al. [20]. In a study by Stockham et al. [16], fever was shown to occur at 18-24 days after E. canis inoculation. In the same manner, epistaxis was not consistently seen in infected patients. David et al. [32] suggested that it is the most dramatic sign of the disease in experimentally infected German shepherd dogs. Based on records, it can be deduced that not all the observed clinical signs with the highest frequency are congruent with the other reports. Thus, clinical signs of CME appear to be varied and non-specific. This may be attributed to the infection of E. canis to circulating monocytes, which affects different body systems and produce varied clinical signs or combinations [6]. CME can be multi-systemic affecting several organs [32]. It may also be due to the different disease stages of the presented animals [6].
The evidence available consists of all retrospective studies. Retrospective studies are low on the hierarchy of evidence due to the difficulty in avoiding sources of bias and confounding. Inconsistent findings were found between the critically reviewed studies and could be due to a variety of reasons including study design, disease processes that led to complete splenectomy, inclusion and exclusion criteria, and inconsistent follow-up times, among other reasons. Based on the weak level of evidence and inconsistent findings, it is difficult to make a conclusion regarding the benefit of performing concurrent gastropexy in dogs receiving splenectomy.
Micro-computed tomography techniques have been developed and reported for non-invasive monitoring of various respiratory diseases modeled in rodents[1] -[7] . To obtain structural and functional information from the images, respiratory-gated imaging at multiple time points in the respiratory cycle is required.Both prospective[8] -[11] and retrospective[12] -[14] techniques have been previously reported.Prospective gating techniques ensure that all projection views are acquired in the desired respiratory phase; however, multiple image acquisitions of different respiratory phases are required to provide sufficient data to measure lung function.Retrospective gating acquires projection views throughout the respiratory cycle, with the projections sorted based on the phase of the respiratory cycle the animal was in when the projection was acquired.Although any portion of the respiratory cycle can be reconstructed, some of the data will be discarded because it is not in the desired phase, which may lead to missing view artefacts in the image or increased X-ray dose to the animal due to acquiring redundant projections for a given phase in the cycle.
For retrospective gating, improvements in the projection selection algorithms may improve the signal-to-noise ratio and reduce or eliminate artefacts due to missing projection views and respiratory motion.Ford et al. describe a method using a temporal window positioned at a specific portion of the externally monitored respiratory trace to select the projections that were acquired during the desired respiratory phase[12] .Since the respiratory trace was based on the motion of the diaphragm monitored externally, the motion of the diaphragm and the recorded trace may not be perfectly synchronized.Furthermore, for free-breathing animals, the portion of the trace that is included in the window may be slightly different from breath-to-breath.An alternate means of retrospectively gating uses information from the projection views to determine the respiratory phase during which the projection was acquired.Hu et al. used the diaphragm position to select projections[13] , whereas Ertelet al. measured diaphragm motion with a Kymogram function to select projections from the desired respiratory phase[14] .Ertel demonstrated a reduction in blurring with good temporal efficiency using the Kymogram technique.Armitageet al. implemented a least error method to ensure that all angular positions were filled in the reconstructed image [20] .In this approach, redundant projections are required at each angle, and some of the angular positions may not exactly be in the same respiratory phase, but image quality metrics showed an improvement for phantom images.
In this paper, we aim to optimize our previously reported[12] scanning protocols for retrospectively respiratory-gated micro-CT imaging for rats to reduce the imaging time and X-ray dose to the animal. We also investigate the effects of including projection views that are not quite in phase to completely fill projection space and eliminate missing view artefacts in the resulting images.Quantitative measurements of image quality and physiologically relevant metrics will be performed in the images using only in-phase projections and compared with those images that add nearly in-phase projections to completely fill projection space.
During the scanning protocol, the animals were free-breathing but under anaesthesia.The micro-CT scanner was a high-speed, cone beam CT scanner (Locus Ultra, General Electric HealthCare, London, Canada), which has been characterised previously [21] -[23] .The scanning protocol acquired 4160 projection views over 10 continuous gantry rotations at 80 kVp and 50 mA with a 50 s X-ray exposure time (5 s per gantry rotation), in accordance with the optimized exposure settings described by Du et al.[23] .The acquisition time for each projection was 12 ms. The entrance dose for this protocol has been measured previously and is approximately 0.28 Gy in air at scanner isocentre[12] .For calibration purposes, a small tube of water is included in each image to convert the recorded signal intensities into Hounsfield units.
A retrospective respiratory-sorting algorithm was used to identify the projections that were acquired during each desired phase of the respiratory cycle.Retrospectively sorting the projection data allows images to be reconstructed at any phase of the respiratory cycle from a single acquisition; however, since some of the projection views are rejected because they are not in the specified phase, the images may suffer from reduced image quality if projection space is not completely filled.To assess the effects of missing view artefacts in the images, we reconstructed each dataset using two respiratory sorting techniques, in-phase and least error, outlined below.
Using a similar approach to our previous work describing an optimized retrospective gating technique for use with mice [12] , we optimized the protocol for imaging the lungs of rats to improve measurements of physiologically relevant parameters with minimal loss of image quality.In the previous mouse study, we only included in-phase projections in the reconstructed images.Optimization of the technique is needed for different species due to the differences in respiratory rates.To optimize the technique for rats, we simulated scanning with fewer gantry rotations, implying fewer projections acquired but with a shorter scan-time and lower dose. We reconstructed images using all 10 rotations, using the first 9 rotations, and so on down to 3 rotations, at which point the image quality suffered from too few projections acquired in the desired respiratory phase.We reconstructed images using continuous gantry rotations ranging from 3 to 10 to optimize between the image quality, scan time and x-ray dose delivered to the animal for both sets of images (in-phase and least error) gated to peak inspiration and to end expiration. 2ff7e9595c
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