Kangjae Yi

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.

Evaluation of fluid leakage into the canine vitreous humor during phacoemulsification using contrast‐enhanced magnetic resonance imaging

OBJECTIVE To evaluate the effects of phacoemulsification with different fluidic parameters on the intraocular tissues using contrast-enhanced magnetic resonance imaging (CE-MRI). PROCEDURES Phacoemulsification with intraocular lens (IOL) implantation was performed on 10 pairs of enucleated canine eyes. Irrigation fluid containing diluted MRI contrast agent was used, with the bottle height/the vacuum pressure set at 50 cm/80 mmHg for one eye (Group L) and at 120 cm/150 mmHg for the opposite eye (Group H). CE-MRI was carried out immediately after phacoemulsification to evaluate the presence of anterior hyaloid membrane detachment (AHD) and the leakage volume-to-vitreous volume ratio (LV/VV%). The ultrasound time, the volume of irrigation solution used, and the total irrigation time were recorded. RESULTS AHD was seen in seven of the 10 eyes in Group L and in nine of the 10 eyes in Group H. Fluid leakage into the vitreous humor (LV/VV%) was significantly greater in Group H than in Group L (P < 0.01). The LV/VV% was also correlated with the total irrigation time in both groups (P < 0.05). The volume of irrigation solution used in Group H was significantly greater than that used in Group L (P < 0.001). There was no statistically significant difference in the ultrasound time between the two groups. CONCLUSIONS Low fluidic parameters led to decreased fluid passage through the zonules, reducing fluid passage into the vitreous. These may also lead to reduced surgical stress on the intraocular tissues by decreasing the amount of irrigation solution used during phacoemulsification in the dog.

Contrast-enhanced ultrasound analysis of renal perfusion in normal micropigs.

Contrast-enhanced ultrasound is one of method for evaluating renal perfusion. The purpose of this project was to assess perfusion patterns and dynamics in normal micropig kidney using ultrasonographic contrast media. Eight young healthy micropigs were included in this study. Micropigs were anesthetized with propofol and received an intravenous bolus of microbubble contrast media through an ear vein. Time/mean pixel value (MPV) curves were generated for selected regions in the right renal cortex and medulla. The parenchyma was enhanced in two phases. The cortex was first enhanced followed by a more gradual enhancement of the medulla. A significant difference in perfusion was detected between the cortex and medulla. Following the bolus injection, the average upslope was 0.68 ± 0.27 MPV/sec, downslope was -0.27 ± 0.13 MPV/sec, baseline was 73.9 ± 16.5 MPV, peak was 84.6 ± 17.2 MPV, and time-to-peak (from injection) was 17.5 ± 6.6 sec for the cortex. For the medulla, the average upslope was 0.50 ± 0.24 MPV/sec, downslope was -0.12 ± 0.06 MPV/sec, baseline was 52.7 ± 7.0 MPV, peak was 65.2 ± 9.3 MPV, and time-to-peak (from injection) was 27.5 ± 5.0 sec. These data can be used as normal reference values for studying young micropigs.

Clinical applications and characteristics of apparent diffusion coefficient maps for the brain of two dogs

Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping are functional magnetic resonance imaging techniques for detecting water diffusion. DWI and the ADC map were performed for intracranial lesions in two dogs. In necrotizing leukoencephalitis, cavitated lesions contained a hypointense center with a hyperintense periphery on DWI, and hyperintense signals on the ADC maps. In metastatic sarcoma, masses including a necrotic region were hypointense with DWI, and hyperintense on the ADC map with hyperintense perilesional edema on DWI and ADC map. Since DWI and ADC data reflect the altered water diffusion, they can provide additional information at the molecular level.

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.