CT imaging features of fat stranding in cats and dogs with abdominal disorder

BackgroundFat stranding is a non-specific finding of an increased fat attenuation on computed tomography (CT) images. Fat stranding is used for detecting the underlying lesion in humans.ObjectivesTo assess the clinical significance of fat stranding on CT images for identifying the underlying cause in dogs and cats.MethodsIn this retrospective study, the incidence, location, extent, distribution, and pattern of fat stranding were assessed on CT studies obtained from 134 cases.ResultsFat stranding was found in 38% (51/134) of all cases and in 35% (37/107) of tumors, which was significantly higher in malignant tumors (44%) than benign tumors (12%). Moreover, fat stranding was found in more than two areas in malignant tumors (16/33) and in a single area in benign tumors (4/4). In inflammation, fat stranding was demonstrated in 54% (7/13) in a single area (7/7) as a focal distribution (6/7). In trauma, fat stranding was revealed in 50% (7/14) and most were in multiple areas (6/7). Regardless of the etiologies, fat stranding was always around the underlying lesion and a reticular pattern was the most common presentation. Logistic regression analysis revealed that multiple areas (p = 0.040) of fat stranding and a reticulonodular pattern (p = 0.022) are the significant predictors of malignant tumor.ConclusionsThese findings indicated that CT fat stranding can be used as a clue for identifying the underlying lesion and can be useful for narrowing the differential list based on the extent and pattern.     

土壤大孔隙及其研究方法

  目的  土壤大孔隙是土壤水气迁移交换的主要通道,研究土壤大孔隙与水分入渗特征对探究水文连通时空变化强烈的山丘区坡地有重要意义,可为红壤丘陵区土地高效利用提供参考。  方法  研究通过电子计算机断层扫描技术和双水头渗透计法,定量研究了粤北红壤丘陵区不同土地利用方式土壤大孔隙与水分入渗特征。  结果  不同土地利用方式的土壤理化性质存在明显差异。林地为砂质黏壤土,园地为黏土,耕地为黏壤土,土壤容重随着土层深度的增加而变大,土壤有机质含量随土层深度的增加而减小。土壤大孔隙度、大孔隙总体积和总表面积表现为：林地 > 园地 > 耕地,大孔隙数量则表现为：园地 > 林地 > 耕地,随着土层深度的增加,土壤大孔隙度和大孔隙数量呈减少趋势;土壤大孔隙平均直径表现为：林地 > 耕地 > 园地,不同土地利用方式的土壤大孔隙直径都主要集中在0 ~ 3 mm。土壤大孔隙度与土壤容重呈显著负相关,与有机质和砂粒含量呈显著正相关性。土壤饱和导水率表现为：园地 > 林地 > 耕地,土壤饱和导水率除受容重影响外,还与有机质含量、大孔隙长度相关。  结论  不同土地利用方式会使大孔隙和饱和导水率等土壤理化性质产生显著差异。林地的大孔隙度和大孔隙总表面积最大,而园地的大孔隙数量和饱和导水率最大。     

PROSPECTIVE COMPARISON OF TUMOR STAGING USING COMPUTED TOMOGRAPHY VERSUS MAGNETIC RESONANCE IMAGING FINDINGS IN DOGS WITH NASAL NEOPLASIA: A PILOT STUDY

Identification of nasal neoplasia extension and tumor staging in dogs is most commonly performed using computed tomography (CT), however magnetic resonance imaging (MRI) is routinely used in human medicine. A prospective pilot study enrolling six dogs with nasal neoplasia was performed with CT and MRI studies acquired under the same anesthetic episode. Interobserver comparison and comparison between the two imaging modalities with regard to bidimensional measurements of the nasal tumors, tumor staging using historical schemes, and assignment of an ordinal scale of tumor margin clarity at the tumor‐soft tissue interface were performed. The hypotheses included that MRI would have greater tumor measurements, result in higher tumor staging, and more clearly define the tumor soft tissue interface when compared to CT. Evaluation of bone involvement of the nasal cavity and head showed a high level of agreement between CT and MRI. Estimation of tumor volume using bidimensional measurements was higher on MRI imaging in 5/6 dogs, and resulted in a median tumor volume which was 18.4% higher than CT imaging. Disagreement between CT and MRI was noted with meningeal enhancement, in which two dogs were positive for meningeal enhancement on MRI and negative on CT. One of six dogs had a higher tumor stage on MRI compared to CT, while the remaining five agreed. Magnetic resonance imaging resulted in larger bidimensional measurements and tumor volume estimates, along with a higher likelihood of identifying meningeal enhancement when compared to CT imaging. Magnetic resonance imaging may provide integral information for tumor staging, prognosis, and treatment planning.     

COMPUTED TOMOGRAPHIC ANATOMY OF THE CANINE INNER AND MIDDLE EAR

A series of high-resolution computed x-ray tomography (CT) images of the normal canine middle and inner ear are presented to serve as a reference for optimal interpretation of clinical CT images of animals with diseases affecting this region.     

COMPUTED TOMOGRAPHIC APPEARANCE OF A NORMAL VARIANT OF THE CANINE TENTORIUM CEREBELLI OSSEUM

A nine-year-old German Shepherd dog presented to the Veterinary Teaching Hospital at North Carolina State University with an eleven-day history of progressive depression, lethargy, inability to walk, blindness and intermittent vomiting. Computed tomography (CT) of the brain was unremarkable; however, bilateral regions of low photon absorption were noted within the tentorium cerebelli osseum. Mean CT numbers of −47.9 Hounsfield units (HU) and −26.4 HU were recorded within the left and right areas, respectively. These areas most likely represent diploë and are presumably a normal variant of the canine skull. A possible explanation for this finding includes a developmental variant where the medial and lateral plates of the tentorium cerebelli osseum fail to fuse, thus leaving a space for diploë accumulation. Use of various combinations of CT windows and numbers can be valuable for characterizing such variants.     

CT2000、T101在集约化鸡场的应用及其对蛋壳品质的影响

1 50 0只 455日龄伊莎褐蛋鸡 ,随机分为对照组、CT2 0 0 0组和T1 0 1组 3组。各组日粮处理分别为 :对照组为基础日粮 ;CT2 0 0 0组为基础日粮 +40 0mg/kgCT2 0 0 0 ;T1 0 1组为基础日粮 +1 0mg/kgT1 0 1。试验为期 9周。结果表明 :与对照组比较 ,CT2 0 0 0、T1 0 1可显著提高产蛋后期蛋鸡生产性能 ;CT2 0 0 0组蛋壳厚度平均增加 0 0 0 3cm (P <0 0 1 ) ,蛋壳强度提高 0 0 4 1kg/cm2 (P <0 0 1 ) ;T1 0 1组蛋壳厚度平均增加 0 0 0 2cm (P <0 0 1 ) ,蛋壳强度提高 0 0 9kg/cm2 ,但各组蛋形指数无显著变化 (P >0 0 5)。结论 :CT2 0 0 0与T1 0 1均可以改善蛋壳品质 ,但CT2 0 0 0效果更好     

基于人工神经网络的原木CT图像缺陷识别

以欧洲白蜡为例,利用训练好的神经网络识别原木CT图像中的各种木材缺陷.不同隐蔽层节点的神经网络可以正确地识别树皮、节子、腐朽和无疵木材;但是对于细小裂纹尚还不能准确识别.计算机快速、自动识别图像中的各种缺陷,有利于实现最优化的锯切方案.     

Predicting spiral grain by computed tomography of Norway spruce

Spiral grain is a feature of wood that affects the shape of the sawn timber. Boards sawn from logs with a large spiral grain have a tendency to twist when the moisture content changes. The aim of this study was to investigate the possibility of predicting spiral grain based on variables that should be measurable with an X-ray LogScanner. The study was based on 49 Norway spruce (Picea abies) logs from three stands in Sweden. The logs were scanned with a computed tomography (CT) scanner every 10mm along the log. Concentric surfaces at various distances from the pith were then reconstructed from the stack of CT images. The spiral grain angle was measured in these concentric surface images, and a statistical model for predicting spiral grain was calibrated using partial least squares (PLS) regression. The PLS model predicts the spiral grain of a log at a distance 50mm from the pith based on different variables that should be measurable with an industrial X-ray LogScanner. The result was a PLS model withR ²=0.52 for the training set andR ²=0.37 for the test set. We concluded that it should be possible to predict the spiral grain of a log based on variables measured by an industrial X-ray LogScanner. The most important variables for predicting spiral grain were measures of sapwood content, variation in the ratio between the heartwood and log areas, and the standard deviation for the mean log density in 10mm thick cross slices along the log. The accuracy when sorting the logs into two groups with spiral grain of 2.0° and of <2.0°, respectively, was 84% of the correctly sorted logs.     

A computed tomography–based method for the assessment of canine retrobulbar cone volume for ophthalmic anaesthesia

ObjectiveTo develop a comprehensive formula for calculating the volume of local anaesthetic solution used for retrobulbar anaesthesia in dogs with different skull morphologies.Study designRetrospective cohort imaging study.AnimalsSkull computed tomography (CT) images of 188 dogs of different breeds collected between January 2009 and December 2017.MethodsAnatomical integrity of the orbit and adjacent structures, presenting complaint, clinical signs and CT findings were verified to exclude ocular abnormalities. The volume of the retrobulbar cone of 376 eyes was calculated using CT scans of the dogs’ skulls. Additional data recorded included morphology of the skull, body weight, sex and size of the dogs, all of which were matched for possible association to the retrobulbar cone volume through univariable and multivariable linear regression models. Results of linear regression models were expressed as estimated beta coefficients with the corresponding 95% confidence intervals (95% CIs).ResultsUsing univariate analysis, the retrobulbar cone volume was positively associated with weight and male sex. In addition, brachycephalic and dolichocephalic dogs showed a larger retrobulbar cone volume than mesocephalic dogs, while sex was no longer significantly associated with the retrobulbar cone volume. In multivariate analysis, when considering all variables in the model, weight emerged as the strongest predictor (beta coefficient: 0.062 mL kg^–1, 95% CI: 0.056–0.067 mL kg^–1, p < 0.001).Conclusionsand clinical relevance In the veterinary literature, there is no agreement on the precise volume of local anaesthetic solution that should be used to achieve intraconal retrobulbar anaesthesia in dogs. Here we suggest a formula to calculate the retrobulbar cone volume and, accordingly, the injection volume of local anaesthetic solution for effective retrobulbar anaesthesia.