Computed tomographic features of focal lipogranulomatous lymphangitis for differentiating from malignant intestinal lesions in a dog

An eight-year-old Maltese dog presented with diarrhea and anorexia. Ultrasonography revealed marked focal wall thickening with loss of layering in the distal ileum. Contrast-enhanced computed tomography (CT) revealed a preserved wall layer with hypoattenuating middle wall thickening. In some segments of the lesion, small nodules protruding toward the mesentery from the outer layer were observed. Histopathology revealed focal lipogranulomatous lymphangitis (FLL) with lymphangiectasia. This is the first report to describe the CT features of FLL in a dog. CT features of preserved wall layers with hypoattenuating middle wall thickening and small nodules can assist in diagnosing FLL in dogs.

Assessment of neovascularization during bone healing using contrast-enhanced ultrasonography in a canine tibial osteotomy model: a preliminary study

Assessment of neovascularization during bone healing using contrast-enhanced ultrasonography in a canine tibial osteotomy model: a preliminary study

Blood perfusion of skeletal muscle and callus was evaluated using contrast-enhanced ultrasonography (CEUS) in a canine osteotomy model to determine the applicability of CEUS in the assessment of neovascularization during fracture healing and to compare the vascular signals on CEUS between external skeletal fixation and cast-applied dogs. In 6 Beagle dogs, a simple transverse osteotomy was performed at the left tibial shaft and external skeletal fixation (n = 3) or a cast (n = 3) was applied. Radiography, power Doppler ultrasonography (power Doppler), and CEUS were performed until complete union was achieved. On CEUS, vascular changes were quantitatively evaluated by measuring peak intensity (PI) and time to PI in the soft tissue and callus and by counting the vascular signals. Vascular signals from the soft tissue were detected on power Doppler and CEUS on day 2. Significantly more vascular signals were detected by CEUS than by power Doppler. On CEUS, PI in the surrounding soft tissue was markedly increased after the fracture line appeared indistinctively changed on radiography in all dogs. In the cast-applied dogs, vascular signals from the periosteal and endosteal callus were detected on CEUS before mineralized callus was observed on radiography. CEUS was useful in assessing the vascularity of soft tissue and callus, particularly in indirect fracture healing, and provided indications of a normally healing fracture.

Assessment of neovascularization during bone healing using contrast-enhanced ultrasonography in a canine tibial osteotomy model: a preliminary study

Blood perfusion of skeletal muscle and callus was evaluated using contrast-enhanced ultrasonography (CEUS) in a canine osteotomy model to determine the applicability of CEUS in the assessment of neovascularization during fracture healing and to compare the vascular signals on CEUS between external skeletal fixation and cast-applied dogs. In 6 Beagle dogs, a simple transverse osteotomy was performed at the left tibial shaft and external skeletal fixation (n = 3) or a cast (n = 3) was applied. Radiography, power Doppler ultrasonography (power Doppler), and CEUS were performed until complete union was achieved. On CEUS, vascular changes were quantitatively evaluated by measuring peak intensity (PI) and time to PI in the soft tissue and callus and by counting the vascular signals. Vascular signals from the soft tissue were detected on power Doppler and CEUS on day 2. Significantly more vascular signals were detected by CEUS than by power Doppler. On CEUS, PI in the surrounding soft tissue was markedly increased after the fracture line appeared indistinctively changed on radiography in all dogs. In the cast-applied dogs, vascular signals from the periosteal and endosteal callus were detected on CEUS before mineralized callus was observed on radiography. CEUS was useful in assessing the vascularity of soft tissue and callus, particularly in indirect fracture healing, and provided indications of a normally healing fracture.

Electromagnetic tracking-based ultrasound/computed tomography fusion imaging in dogs: preliminary application to ocular and periocular regions

In ultrasound/computed tomography (CT) fusion images, ultrasound allows visualization of the target in real time. CT provides a navigation for ultrasound scanning and improves the overview in areas of limited visualization with ultrasound. This study was performed to investigate the feasibility of ultrasound/CT fusion based on an electromagnetic tracking technique using external fiducial markers for canine ocular and periocular regions. In 7 Beagle dogs, contrast-enhanced CT images of the head were obtained with placing external fiducial markers over the frontal region and both sides of the forepaws of the dog. Ultrasonography was performed under a magnetic field by installing a position sensor in the linear probe, without changing the dog's position. The positions of the external fiducial markers were adjusted and matched, based on the CT images. The execution time of co-registration and the distance between the regions of interest and the co-registration points, the frontal bone, cornea, retina, and optic nerve, were estimated. Approximately 60% of external fiducial markers were properly recognized in all dogs. After adjustment, all external fiducial markers were precisely matched. The co-registration execution time was less than 1 min. The distances between the regions of interest and co-registration points were less than 3 mm in all dogs. The electromagnetic tracking technique using external fiducial markers was a simple and applicable method for fusion imaging of a canine head using real-time ultrasonography and CT. This technique can be useful for interventional procedures of retrobulbar and periorbital lesions.

Ultrasound-guided transhepatic computed tomography cholecystography in beagle dogs

This study was performed to evaluate the feasibility of ultrasound-guided computed tomography (CT) cholecystography and to establish an optimal protocol. In 8 healthy beagles, CT cholecystography was conducted using four contrast formulas; two dilution ratios (1:1 vs. 1:3) and two total volumes (8 mL vs. 16 mL) of 300 mgI/kg iohexol after ultrasound-guided percutaneous contrast injection into the gallbladder. CT images were obtained at 3, 10, and 30 min after injection and assessed qualitatively and quantitatively. For all contrast formulas, CT cholecystography showed the gallbladder and the intra- and extrahepatic bile ducts. The volume of the gallbladder and size of bile duct were significantly larger when using a volume of 16 mL iohexol than an 8 mL volume regardless of the dilution ratio. The distinction between the common bile duct and duodenum, the filling of the gallbladder, and the patency of bile duct were effectively assessed using a 16 mL volume of contrast agent with either dilution ratio. Beam-hardening artifacts deteriorated CT image quality for visualizing the biliary system when using the dilution ratio of 1:1. Patency of the bile tract could be easily evaluated using a curvilinear planar reconstruction. There was no significant difference in CT scan time among the different conditions. Minor leakage of contrast agent temporarily occurred after contrast injection in 30% of 32 sets of CT cholecystography. Ultrasound-guided percutaneous cholecystography can visualize both gallbladder and biliary tract with minimal artifacts using a contrast agent volume of 16 mL with a 1:3 dilution ratio.

Variation of canine vertebral bone architecture in computed tomography

Focal vertebral bone density changes were assessed in vertebral computed tomography (CT) images obtained from clinically healthy dogs without diseases that affect bone density. The number, location, and density of lesions were determined. A total of 429 vertebral CT images from 20 dogs were reviewed, and 99 focal vertebral changes were identified in 14 dogs. Focal vertebral bone density changes were mainly found in thoracic vertebrae (29.6%) as hyperattenuating (86.9%) lesions. All focal vertebral changes were observed at the vertebral body, except for a single hyperattenuating change in one thoracic transverse process. Among the hyperattenuating changes, multifocal changes (53.5%) were more common than single changes (46.5%). Most of the hypoattenuating changes were single (92.3%). Eight dogs, 40% of the 20 dogs in the study and 61.6% of the 13 dogs showing focal vertebral changes in the thoracic vertebra, had hyperattenuating changes at the 7th or 8th thoracic vertebra. Our results indicate that focal changes in vertebral bone density are commonly identified on vertebral CT images in healthy dogs, and these changes should be taken into consideration on interpretation of CT images.

Clinical usefulness of post-operative 18F-fluorodeoxyglucose positron emission tomography-computed tomography in canine hemangiosarcoma

This report describes the usefulness of positron emission tomography-computed tomography (PET-CT) for evaluating recurrent or residual tumors following surgery. CT and 18F-fluorodeoxyglucose PET-CT were pre- and post-operatively applied to multiple masses in a dog with hemangiosarcoma. The distinction between the left subcutaneous mass and the peritoneum was clarified on pre-operative CT examination, and malignancy was suspected based on PET-CT. A recurrent or residual tumor in the left subcutaneous region was suspected on post-operative PET-CT, and confirmed through histopathologic examination.

Tissue Doppler and strain imaging of left ventricle in Beagle dogs with iatrogenic hypercortisolism

Changes in radial and longitudinal left ventricular (LV) function were investigated in beagles with iatrogenic hypercortisolism. A total of 11 normal dogs were used, and 2 mg/kg prednisone was administered per oral q12 h for 28 days to 7 out of 11 dogs to induce iatrogenic hypercortisolism. Body weight, blood pressure, conventional echocardiography and tissue Doppler imaging (TDI) of normal and iatrogenic hypercortisolism groups were conducted. The myocardial wall velocity of the LV was measured using color TDI and myocardial deformation was determined by the strain and strain rate. Conventional echocardiography revealed that the diastolic LV free wall and interventricular septum in the hypercortisolism group were thickened relative to those in the normal group. The peak early diastolic myocardial velocity and early to late diastolic myocardial velocity ratio of TDI in the hypercortisolism group were significantly lower than those in the normal group. The strain values in the hypercortisolism group were significantly lower than those in the normal group, particularly for longitudinal wall motion. The lower values of myocardium from TDI and strain imaging could be used to investigate subclinical LV systolic and diastolic dysfunction in dogs with the iatrogenic hypercortisolism.