Ki-Ja Lee

Comparison of the diagnosis of intervertebral disc herniation in dogs by CT before and after contrast enhancement of the subarachnoid space

Eleven miniature dachshunds with a herniated intervertebral disc were examined by CT, first before and then after contrast enhancement of the subarachnoid space. The images were classified into three grades by three veterinarians. In four cases, lesions observed on the scans obtained after contrast enhancement had not been observed on the preliminary scans and in one case a lesion observed on the preliminary scan was not observed on the scan obtained after contrast enhancement. Hemilaminectomies were performed on the basis of the enhanced CT results, and a clinical improvement was observed in each of the dogs. Calcification was detected in all the samples of herniated intervertebral disc material.

Clinical experience of using multidetector-row CT for the diagnosis of disorders in cattle

To determine the clinical usefulness of multidetectorrow CT for the diagnosis of disorders in cattle, images were obtained from 27 cattle, which were then subjected to postmortem and histopathological examinations. The cattle were divided into three categories of disorder: neurological (18 cases), skeletal (four cases) and other (five cases). In five cattle, which were suspected to have brain diseases, no abnormalities were identified by either CT or histopathological examination. Eight types of lesions were detected by CT in the cattle with neurological and vestibular disorders. The diseases diagnosed included hydrocephalus (three cases), intracranial arachnoid cysts (three cases), otitis media (five cases), cerebral abscess (one case), meningoencephalocele (one case), porencephaly (one case), bicephalus (one case) and rupture of the spinal cord (one case). Lesions were identified in all the cattle with skeletal disorders, including luxation (two cases), fracture (two cases), spondylosis (one case) and congenital disorders of the skeletal system (one case). Morphological disorders in the eyes (one case), nasal cavity (two cases), frontal sinuses (one case), thyroid glands (two cases), lung fields (two cases) and abdominal organs (two cases) were diagnosed by CT.

Virtopsy in a Red Kangaroo with Oral Osteomyelitis

Abstract This report describes the use of computed tomography (CT) in a nondomestic species. Postmortem CT was performed on a red kangaroo (Macropus rufus) and a diagnosis of oral osteomyelitis was made. CT examination revealed bony remodeling of the right mandible, an intraosseous lesion of the right temporal bone, muscle necrosis around the right mandible, and the absence of the right, first, upper molar tooth. Cardiac and intrahepatic gas and a distended intestine due to postmortem gas accumulation were also seen. All the lesions identified with CT were also identified by conventional necropsy, except the cardiac and intrahepatic gases. Virtopsy may be a useful procedure for the noninvasive identification of cause of death and as a guide for necropsy in animals.

Computed tomography of the prostate gland in apparently healthy entire dogs

OBJECTIVES To describe the computed tomography (CT) features of the prostate gland and determine prostate size using CT in entire male dogs. METHODS The prostate gland was evaluated in 35 dogs. Morphological features including homogeneity, delineation, shape and intraprostatic differentiation were assessed. Height, length, width, area, volume and attenuation values of the prostate gland were measured. Ratios of prostatic height (rH), length and width to the sixth lumbar vertebral body length were calculated. Relationships of prostatic dimensions with body weight and age were evaluated. RESULTS The prostate gland was homogeneous in 29 dogs on non-contrast images and 18 of 24 dogs on postcontrast images. Transverse images revealed a semi-oval prostate gland in 29 dogs and irregularly shaped prostate gland in 6 dogs. A prominent median septum was observed in postcontrast images. Significant positive correlations were found between body weight and age and all prostatic dimensions except between age and rH. The mean ± sd values for attenuation were 59·3 ± 9·1 and 121·3 ± 22·7 HU in non-contrast and postcontrast image, respectively. CLINICAL SIGNIFICANCE CT can be useful for evaluating morphological features of the prostate gland. Prostatic length or width is a better measure than height for computed tomographic estimation of prostate size.

Influence of osmolarity of contrast medium and saline flush on computed tomography angiography: Comparison of monomeric and dimeric iodinated contrast media with different iodine concentrations at an identical iodine delivery rate

PURPOSE To evaluate the influence of osmolarity of iodinated contrast media and saline flush on the contrast effect in thoracic computed tomography angiography (CTA) at an identical iodine delivery rate (IDR). MATERIALS AND METHODS Seven beagles were used in a cross-over experiment. The contrast media used were iohexol 350 mgI/ml (IOH350; osmolarity 844 mmol/kg) and iodixanol 320 mgI/ml (IDX320; osmolarity 290 mmol/kg). Each contrast medium was administered to groups with and without saline flush at 40.0 mgI/kg/s for all experiments. Dynamic CT scanning was performed at the ninth thoracic vertebra level. The peak value, area under the curve (AUC), and time to peak (TTP) were calculated from the time attenuation curves of the pulmonary artery and aorta. RESULTS There was no significant difference between IOH350 and IDX320 with or without saline flush in the peak values for the pulmonary artery and aorta. AUC was significantly higher in groups with saline flush for both contrast media and arteries (p<0.05) with no significant difference between contrast media. TTP was significantly longer in groups with saline flush than without saline flush for both contrast media and arteries (p<0.05), with no significant difference between contrast media. CONCLUSIONS There were no significant differences in the contrast effects of monomeric IOH350 and dimeric IDX320 in thoracic CTA when used at an identical IDR. Moreover, saline flush prolonged the peak duration at 600 mgI/kg.

Effect of a saline chaser for contrast enhancement of computed tomographic angiography in cattle.

Computed tomographic angiography was performed on nine normal Holstein calves in a crossover method to investigate the effect of a saline chaser for enhancement of the maxillary arteries and dorsal sagittal sinus. One group was administered a contrast injection (600 mg iodine/kg at 4 ml/s) followed by 50 ml of a saline chaser at the same rate as the contrast material. The second group was administered a contrast injection without a saline chaser. Addition of the saline chaser to the contrast material resulted in a higher peak attenuation in the maxillary artery (244.45 ± 36.19 v 202.20 ± 27.07, P<0.05) and dorsal sagittal sinus (241.2 ± 31.51 v 198.88 ± 21.09, P<0.05). These results indicate that a contrast injection followed by saline chaser increased uptake in contrast-enhanced CT.

The relationship between the size of caudolateral curvilinear osteophyte of the canine femoral neck and the radiographic view.

Caudolateral curvilinear osteophyte (CCO), an osteophyte at the site of joint capsule attachment on the caudal aspect of the femoral neck, has been advocated as a radiographic criterion for coxofemoral subluxation. The correlation between the presence of CCO on radiographs (radiographic-CCO), the size of the CCO (CCO index) on three-dimensional computed tomographic (CT) images, and hip evaluation using transverse CT images was assessed in 22 Border Collies. CCOs were detected on the radiographs and CT images of 32% and 100% femurs, respectively. The CCO index correlated significantly with radiographic-CCO, but a large CCO index did not necessarily imply that the CCO was visible on radiographs. Hence, radiographic-CCO findings should be used cautiously in hip evaluation of Border Collies.

Use of a saline chaser to reduce the dose of contrast material for dynamic CT in cattle.

To investigate the effectiveness of a saline chaser in reducing the required dose of contrast material while carrying out dynamic CT scans in cattle, six clinically normal Holstein calves were subjected to CT scans of the head in a study using a crossover design. The calves were studied as three groups: group A received only contrast material (600 mgI/kg); group B received a 30 per cent lower dose of the same contrast material followed by 50 ml of saline solution; and group C received a 40 per cent lower dose of the same contrast material followed by 50 ml of saline solution. In all the animals, a power injector was used for administering the contrast material, with an injection rate of 4 ml/s and a pressure of 4.7 to 5.7 kg/cm2. Attenuation values were obtained from the right and left maxillary arteries and dorsal sagittal sinus. There were no significant differences in the maximum enhancement value (MEV) of the maxillary arteries and dorsal sagittal sinus between groups A and B. The MEVs of the maxillary arteries and dorsal sagittal sinus in groups A and B were significantly greater than the MEV in group C (P<0.05). The use of a saline chaser allowed a 30 per cent reduction in the dose of contrast material without decreasing vascular enhancement.

Magnetic Resonance Characteristics of Ischemic Brain Infarction in Three Dogs

This case study describes the magnetic resonance characteristics of brain infarction in three dogs. Locations of the brain infarcts were cerebella, thalamus, and multifocal. The infarcts were sharply demarcated from adjacent brain parenchyma, homogeneous, T1-hypointense, T2-hyperintense with/without contrast enhancement, and minimal or no mass effect. Diffusion-weighted imaging (DWI) sequences were available in a dog and the infarcts were hyperintense on DWI and were hypointense on the apparent diffusion coefficient map.

Comparison of varying injection rates of saline chasers on intravascular contrast enhancement for dynamic CT in cattle

Dynamic CT was performed in five normal Holstein calves to investigate the effect of saline chasers on intravascular contrast enhancement when administered at three different rates. The five calves were imaged using dynamic CT in a crossover study design. Group A was administered only contrast medium (600 mg iodine/kg, 4 ml/s), while groups B, C and D were administered contrast medium at 30 per cent reduction followed by saline chasers injected at 2, 4 and 8 ml/s, respectively. Attenuation values were obtained from the right and left maxillary arteries and dorsal sagittal sinus. Maximum enhancement value and mean value of the enhancement plateau obtained from the maxillary arteries were significantly lower in group B than in the other groups. The duration of the enhancement plateau was longer in group C than in groups B and D (P<0.05).