Namsoon Lee

Effects of surface modification on the resin-transfer moulding (RTM) of glass-fibre/unsaturated-polyester composites

Abstract The effects of glass fibre surface modification on the flow characteristics of unsaturated polyester (UPE) resin were investigated in the resin-transfer moulding (RTM) process. γ-Methacryloxypropyl trimethoxy silane (γ-MPS) was used as a glass fibre surface modifier. It was found that surface energy of glass fibre was decreased by γ-MPS treatment by advancing contact-angle measurement. Unsteady state permeability of glass fabric preforms was measured according to Darcys law. The apparent permeability of γ-MPS-treated glass fabric preforms was slightly lower than that of untreated fabric performs because of the macro/micro flow induced by capillary action. The void contents and the flexural properties of the cured glass-fibre/UPE composites were estimated and morphological study of the glass-fibre/UPE composites was also performed by SEM. When the fibre surface was treated with γ-MPS, the void content and the flexural properties of the glass-fibre/UPE composites were different in different regions of the mould cavity.

Ultrasound-guided mesenteric lymph node iohexol injection for thoracic duct computed tomographic lymphography in cats.

Computed tomographic (CT) lymphography was performed in cats using percutaneous ultrasound-guided injection of contrast medium into a mesenteric lymph node. The thoracic duct and its branches were clearly delineated in CT images of seven cats studied. The thoracic duct was characterized by anatomic variation and appeared as single or multiple branches. The thoracic duct and the cisterna chyli were identified along the ventral or left ventral aspect of the vertebrae from the level of the cranial lumbar to the caudal cervical vertebrae. The thoracic duct was identified in the central caudal mediastinum, deviated to the left in the cranial mediastinum, and finally moved toward the venous system. Small volumes of extranodal contrast medium leakage were identified in all cats. After injection, the mesenteric lymph nodes were cytologically normal. Ultrasound-guided CT lymphography via percutaneous mesenteric lymph node injection appears safe and effective in cats.

CT THORACIC DUCT LYMPHOGRAPHY IN CATS BY POPLITEAL LYMPH NODE IOHEXOL INJECTION

Three different doses (1.0, 1.5, and 2.0 ml) of iohexol (300 mgl/ml) were injected percutaneously into the popliteal lymph node of eight adult cats under ultrasound guidance. Serial transverse CT images of five regions of interest (L3, T13, T8, T4, and T1 level) were performed at 2-min intervals, and the attenuation in Hounsfield Units (HU) of the lymphatic vessels was measured for determination of the optimal dose of iohexol and CT scan parameters. The optimal dose was 1.5 ml and helical CT acquisition is recommended to be performed as soon as possible after iohexol injection. In helical scans, the thoracic duct was characterized by variable branch numbers that formed a single trunk and entered the venous system at variable levels. CT lymphography using this protocol was performed in a cat with chylothorax. The thoracic duct was tortuous and focally dilated, and leakage of contrast medium was observed. Percutaneous CT lymphography using ultrasound-guided administration of iohexol into the popliteal lymph node appears reliable for delineation of the thoracic duct in cats.

Assessment of feline abdominal adipose tissue using computed tomography

Obesity is a common nutritional disorder in cats and it increases the risk factors for various diseases. The aim of this study is to suggest a method for the evaluation of feline obesity using computed tomography. The attenuation range from −156 to −106 was determined as the range of feline abdominal adipose tissue. With this range, total (TAT), visceral (VAT) and subcutaneous (SAT) adipose tissues were measured. The best correlation between the adipose tissue in cross-sectional image and entire abdomen volume was obtained at the L3 and L5 levels. The mean VAT/SAT ratio was 1.18±0.32, which was much higher than in humans. The cats with an overweight body condition had a significantly lower VAT/SAT ratio than cats with an ideal body condition. This technique may contribute to both the clinical diagnosis and the experimental study of feline obesity.

Zygomatic Sialolithiasis Diagnosed with Computed Tomography in a Dog

ABSTRACT A 10-year-old castrated Shih-Tzu male dog was referred for examination of acute right exophthalmos, protrusion of the third eyelid and soft tissue swelling ventral to the globe. Ultrasonography revealed echogenic fluid around the right globe. Computed tomography (CT) showed an enlarged right zygomatic salivary gland compared with the left zygomatic gland and an amorphous cystic mass ventral to the right globe. Hyperdense material, which we suspected to be a sialolith, was identified in the right zygomatic gland. The zygomatic gland and the cystic lesion were removed, and a zygomatic sialocele with sialolith and ductal obstruction were found by histopathological examination. CT was a useful diagnostic tool for zygomatic sialolithiasis.

Evaluation of diaphragmatic motion in normal and diaphragmatic paralyzed dogs using M-mode ultrasonography.

Diagnosis of unilateral diaphragmatic paralysis in dogs is currently based on fluoroscopic detection of unequal movement between the crura. Bilateral paralysis may be more difficult to confirm with fluoroscopy because diaphragmatic movement is sometimes produced by compensatory abdominal muscle contractions. The purpose of this study was to develop a new method to evaluate diaphragmatic movement using M-mode ultrasonography and to describe findings for normal and diaphragmatic paralyzed dogs. Fifty-five clinically normal dogs and two dogs with diaphragmatic paralysis were recruited. Thoracic radiographs were acquired for all dogs and fluoroscopy studies were also acquired for clinically affected dogs. Two observers independently measured diaphragmatic direction of motion and amplitude of excursion using M-mode ultrasonography for dogs meeting study inclusion criteria. Eight of the clinically normal dogs were excluded due to abnormal thoracic radiographic findings. For the remaining normal dogs, the lower limit values of diaphragmatic excursion were 2.85-2.98 mm during normal breathing. One dog with bilateral diaphragmatic paralysis showed paradoxical movement of both crura at the end of inspiration. One dog with unilateral diaphragmatic paralysis had diaphragmatic excursion values of 2.00 ± 0.42 mm on the left side and 4.05 ± 1.48 mm on the right side. The difference between left and right diaphragmatic excursion values was 55%. Findings indicated that M-mode ultrasonography is a relatively simple and objective method for measuring diaphragmatic movement in dogs. Future studies are needed in a larger number of dogs with diaphragmatic paralysis to determine the diagnostic sensitivity of this promising new technique.

IMAGING ASSESSMENT OF THE MODIFIED DOUBLE CONTRAST BARIUM ENEMA USING CARBOXYMETHYLCELLULOSE ON RADIOGRAPHY AND ULTRASONOGRAPHY IN DOGS

A modified double contrast barium enema using carboxymethylcellulose was evaluated in beagle dogs and compared with dogs receiving a conventional barium enema. The experimental group was divided into three groups (1, 2, and 3) and given 30 ml/kg of different volume ratios of a barium vs. carboxymethylcellulose mixture. Each group underwent sonography following radiography. The volume ratio of one part barium to three parts carboxymethylcellulose was judged to be the optimal mixture, resulting in a general distribution of contrast and bowel radiolucency on radiographs and adequate postradiography sonography. The modified barium enema using carboxymethylcellulose is useful for assessing the general morphology and mucosal layers of the colon simultaneously on radiographs and ultrasonographs.

Evaluation of computed tomographic enterography with an orally administered lactulose solution in clinically normal dogs

OBJECTIVE To determine optimal techniques for CT enterography in clinically normal dogs and to evaluate luminal distention after oral administration of lactulose solution as a contrast agent. ANIMALS 15 healthy dogs. PROCEDURES CT was performed in a control group (2 dogs that underwent CT to evaluate metastasis and 5 other dogs). In a bolus administration group (5 dogs from the control group), lactulose solution (1.34 g/mL) was administered (60 mL/kg) rapidly via gastric tube to anesthetized dogs, and CT was performed every 10 minutes for 1 hour. In a continuous administration group of 8 other dogs, lactulose solution (60 mL/kg) was administered slowly via nasoesophageal tube over a period of 45 minutes. Then, 15 minutes after anesthetic induction, CT was performed every 10 minutes for 1 hour. Luminal distention of the small intestines was evaluated qualitatively by use of a 3-point scale. RESULTS All small intestinal segments had poor luminal distention in the control group. The terminal ileum had poor luminal distention for the bolus administration group. Nearly all segments had good luminal distention for the continuous administration group with mild adverse effects. Luminal distention scores from 0 to 20 minutes after lactulose administration were significantly higher than scores from 30 to 60 minutes. Interobserver reproducibility was high for all intestinal segments. CONCLUSIONS AND CLINICAL RELEVANCE CT performed between 0 and 20 minutes after continuous administration of lactulose solution (60 mL/kg) may reveal adequate luminal distention for examination of small intestinal segments in dogs.

Usefulness of CT imaging for segmental lung lobe torsion without typical radiographic imaging in a Pomeranian.

A 3-year-old, intact female Pomeranian presented with a 1-month history of coughing. Thoracic radiography showed focal infiltration of the left cranial lung lobe and widening of the cranial mediastinum. Subsequent computed tomography revealed torsion of the caudal segment of the left cranial lung lobe, which was confirmed by exploratory thoracotomy. There was no apparent underlying etiology for the condition. To the authors’ knowledge, this is the first report of lung lobe torsion in this breed and the first detailed CT imaging report for segmental lung lobe torsion.