MAGNETIC RESONANCE IMAGING APPEARANCE OF THE CISTERNA CHYLI

Thoracolumbar spinal magnetic resonance imaging (MRI) examinations in dogs frequently include the region of the cisterna chyli within the field of view. It is important to be aware of the appearance and location of this structure to avoid confusing it for a pathologic periaortic lesion. MRI examinations of the thoracolumbar spine were reviewed in 30 dogs. The cisterna chyli was identified in 26 dogs and was most commonly located caudal to the diaphragmatic crura at the level of L4; afferent and efferent lymphatics were seen in all dogs. Transverse T2-weighted images were the most useful to locate the cisterna chyli. It was isointense to fluid on T2-weighted images and isointense to muscle on T1-weighted images. Mild contrast enhancement was seen in three dogs. The cisterna always wrapped around the aorta, but varied in shape, with the most common being the wide right dorsolateral ellipse. The thoracic duct was also visible in 30 dogs. MRI may have potential for noninvasive evaluation of the abdominal and thoracic lymphatic ducts in dogs.     

Comparison of mesenteric lymphadenography performed via surgical and laparoscopic approaches in dogs

OBJECTIVE: To determine whether injection of a mesenteric lymph node with iodinated aqueous contrast medium results in radiographic delineation of the thoracic duct and its branches, ascertain the ideal interval between injection and radiographic imaging, and evaluate mesenteric lymphadenography performed via laparoscopic and surgical approaches in dogs. ANIMALS: 10 adult dogs. PROCEDURE: In each dog, a right paracostal laparotomy or a right laparoscopic approach was performed to identify a mesenteric lymph node for injection of an iodinated aqueous contrast agent (0.22 mL/kg [81.4 mg of iodine/kg]). Lateral radiographic views were obtained at 60, 120, 180, 240, and 300 seconds after injection. RESULTS: A mesenteric lymph node was identified and injected with contrast medium in each dog. Via paracostal laparotomy, lymph node injection resulted in successful lymphangiographic evaluation in 4 of 5 dogs, whereas via the laparoscopic approach, lymph node injection resulted in successful lymphangio-graphic evaluation in 2 of 5 dogs. In successful radiographic evaluations, injected lymph nodes, mesenteric lymphatics, and the thoracic duct and its branches were delineated. Radiographs obtained at 60 and 120 seconds after injection of contrast medium provided the most detail. CONCLUSIONS AND CLINICAL RELEVANCE: Injection of a mesenteric lymph node directly with contrast medium appears to be a feasible technique for delineation of the thoracic duct and its branches in dogs and might be useful in small animals in which mesenteric lymphatic catheterization can be difficult and lymphangiography is more likely to fail. Refinement of the laparoscopic technique may provide a minimally invasive approach to lymphadenography.     

A cardiomyopathy in the English Cocker Spaniel: a clinico-pathological investigation

This report describes some of the characteristics of a cardiomyopathy in English Cocker Spaniels. Forty-nine dogs from a kennel with a history of a cardiomyopathy were assessed clinically, electrocardiographically and radiographically. Angiography, haemodynamic and post-mortem examinations were carried out on selected dogs. On electrocardiographic (ECG) and radiographic criteria the dogs were classified into five groups. Twenty-six dogs (Group 1) were normal. Seven dogs (Group 2) showed ECG changes compatible with left or biventricular hypertrophy in the absence of radiographic abnormality. This was interpreted as concentric hypertrophy. Seven dogs (Group 3) showed ECG and radiographic evidence of cardiac hypertrophy with five of the seven exhibiting enlargement of both chambers. The changes were considered to be compatible with eccentric hypertrophy. Post-mortem findings in dogs with ECG characteristics of Groups 2 and 3 have shown concentric hypertrophy in three cases and eccentric hypertrophy in one case. Six dogs (Group 4) had right axis deviations. Three dogs (Group 5) showed left axis deviations. It is suggested that a cardiomyopathy exists in English Cocker Spaniels initially developing as a concentric hypertrophy and progressing to eccentric hypertrophy. At present the aetiology is unknown.     

Popliteal and mesenteric lymph node injection with methylene blue for coloration of the thoracic duct in dogs

OBJECTIVE:To describe and compare the time of onset and intensity of thoracic duct coloration after injection of methylene blue into a mesenteric or popliteal lymph node. STUDY DESIGN: Experimental study. ANIMALS: Twenty adult dogs. METHODS: A right tenth intercostal thoracotomy, a right paracostal laparotomy, and an approach to the right popliteal lymph node were performed on each dog. Methylene blue (0.5 mg/kg of a 1% solution, maximum 10 mg) was injected into either a mesenteric (group M, 10 dogs) or popliteal (group P, 10 dogs) lymph node. Thoracic duct color was graded (0 to 3) every 5 minutes for 60 minutes. Statistical analysis was performed on mean thoracic duct color grade data, on number of successful outcomes between groups M and P, and between weight groups. RESULTS: Coloration of the thoracic duct occurred in all group M dogs and 6 group P dogs. Coloration was first recorded 0 to 10 minutes after injection in all dogs and persisted for 60 minutes in 15 dogs. Mean thoracic duct color grade was significantly increased postinjection compared with preinjection at all times in group M. More successful outcomes occurred in group M (P =.03). CONCLUSIONS: Methylene blue injected into mesenteric or popliteal lymph nodes was successful in coloring the thoracic duct, but both mean grade and number of successful outcomes were significantly higher after mesenteric injection. CLINICAL RELEVANCE: Thoracic duct coloration after lymph node injection occurred within 10 minutes and persisted for 60 minutes. This information is useful in planning thoracic duct ligation in cases of chylothorax when observation of the duct is desired. Injection of both lymph node sites was successful, but mesenteric node injection was a more reliable technique.     

Malignant haemangioendothelioma (angiosarcoma) in the dog

During the period from January 1969 to January 1975, twenty-five cases of malignant haemangioendothelioma were found in the course of routine post-mortem examinations. One case was observed in the period 1949–1952. The two periods are compared with respect to age, breed and sex of dogs examined.
The Alsatian was represented significantly more than other breeds (eleven out of twenty-five cases) and particularly in cases involving the right atrium (seven Alsatians in a total of eleven cases).
The post-mortem findings and histology are described. It is suggested that there are three groups of cases, namely, primary spleen, primary right atrium and primary at some other site.     

Lymphography of the thoracic duct by percutaneous injection of iohexol into the popliteal lymph node of dogs: experimental study and clinical application

OBJECTIVE: To evaluate the efficacy of percutaneous administration of iohexol into the popliteal lymph node as a non-invasive technique for thoracic duct lymphangiography in dogs. STUDY DESIGN: Experimental study and clinical report. ANIMALS: Normal adult dogs (n=4) and 1 dog with recurrent chylothorax. METHODS: For the experimental study, 4 dogs (weight, 8.4-12.3 kg) had 5-10 mL iohexol injected percutaneously into 1 popliteal lymph node and then thoracic radiographs were taken. Popliteal lymph nodes were examined by histopathology 8 days later. One 25-kg dog with recurrent chylothorax had 25 mL iohexol injected into the right popliteal lymph node followed by thoracic radiography. RESULTS: In experimental dogs, the thoracic duct was best visualized on thoracic radiographs after administration of 10 mL iohexol. Clinically, no abnormalities were identified in the injected limb and except for 1 dog that had large numbers of siderocytes and erythrophagocytic macrophages in the injected lymph node, the histopathologic findings in the other injected popliteal lymph nodes were not different from contralateral nodes. In the clinical case, the thoracic duct was visualized, but there was leakage of iohexol around the node. CONCLUSION: The thoracic duct in dogs can be visualized by lymphography after percutaneous injection of iohexol (1 mL/kg at 2 mL/min) into the popliteal lymph node. CLINICAL RELEVANCE: Percutaneous popliteal lymph node administration of iohexol should be considered as an alternative to mesenteric lymph node injection for radiographic identification of the thoracic duct in dogs.     

Effect of Tamoxifen Citrate on Canine Immobilization (Disuse) Osteoporosis

The effect of tamoxifen citrate on bone mass in immobilization osteoporosis was studied in 11 growing dogs. Immobilization osteoporosis was induced by fiberglass cast immobilization of the right hindlimb for 28 days, while the left hindlimb served as a nonimmobilized control. Six dogs received tamoxifen citrate (1.5 mg/kg per os) once daily for 28 days; five dogs received no treatment. All dogs were euthanatized on day 28 and bone samples were collected. Bone mineral content of the distal tibial metaphysis of casted and uncasted limbs was measured by single photon absorptiometry. Immobilization resulted in a significant reduction in bone mass in the casted limb of untreated and tamoxifen-treated dogs. However, tamoxifen-treated dogs had less severe immobilization osteoporosis than untreated dogs. The calculated bone mass sparing effect of tamoxifen was 24.4%. Because of the complexity of pathologic bone remodeling, use of a single therapeutic agent may not be the optimal means of preventing bone loss associated with immobilization.     

COMPUTED TOMOGRAPHIC CHARACTERISTICS OF PRESUMED NORMAL CANINE ABDOMINAL LYMPH NODES

Though identification of lymph nodes is essential in staging cancer patients, little has been reported about the CT features of canine abdominal lymph nodes. The purpose of this retrospective study was to describe the visibility, location, and characteristics of abdominal lymph nodes in abdominal CT studies of dogs considered unlikely to have lymphadenopathy. The relationship between the number of identified lymph nodes and intraabdominal fat ranking, body weight, and slice thickness was also investigated. A total of 19 dogs were included. At least two jejunal lymph nodes and both left and right medial iliac lymph nodes were identified in all dogs. Colic lymph nodes were not identified in any of the dogs. Visualization of all other lymph nodes varied. There were significantly more lymph nodes visible in dogs with more intraabdominal fat (P < 0.0001). No correlation between the number of identified lymph nodes and body weight (P = 0.64) or slice thickness (P = 0.76) was found. Though most of all identified lymph nodes had an elongated shape, a rounded shape was most common in splenic, pancreaticoduodenal, renal, ileocolic and caudal mesenteric lymph nodes. Most lymph nodes had a homogeneous structure before and following the intravenous administration of contrast medium. Some lymph nodes had a slightly irregular structure or were relatively more hyper attenuating in the periphery than centrally before and/or after contrast administration. Mean attenuation before contrast was 37 Hounsfield Units (HU) (range 20–52 HU), and 109 HU after contrast (range 36–223 HU). Findings indicated that the CT visibility, characteristics of different abdominal lymph nodes may be variable in dogs.     

ULTRASONOGRAPHIC CHARACTERISTICS OF THE CISTERNA CHYLI IN EIGHT DOGS AND FOUR CATS

Ultrasonography of the cisterna chyli has been used in humans to diagnose increased lymphatic flow or lymph flow obstruction and to guide percutaneous embolization of the thoracic duct via the cisterna chyli. The aim of this study was to describe the ultrasonographic characteristics of the dorsal portion of cisterna chyli in dogs and cats with chylous ascites or chylothorax and in a group of healthy dogs and cats. The aorta and the cranial mesenteric artery were used as anatomic landmarks. Ultrasonography was performed before and 2 h after a fatty meal in healthy dogs and cats. The visualized structure was confirmed to be a dilated cisterna chyli at necropsy in a dog with chylous ascites. The confirmed or presumed cisterna chyli was consistently detected using ultrasonography in nonfasted healthy animals and clinically affected animals and appeared as an anechoic tubular structure, without detectable flow, at the right dorsolateral aspect of the aorta. It had a similar ultrasonographic appearance in patients with chyloabdomen and in nonfasted healthy dogs and cats. There was considerable overlap in diameters of the cisterna chyli for affected and healthy animals. The shape and size of the cisterna chyli in an individual animal were variable during the same ultrasound examination and between different examinations. This study demonstrated the appearance of the presumed dorsal portion of the cisterna chyli by ultrasonography and might provide useful preliminary data for further studies into the feasibility of ultrasound‐guided injections or aspirations of the cisterna chyli in dogs and cats.     

Idiopathic hemorrhagic pericardial effusion in eight dogs

Idiopathic hemorrhagic pericardial effusion was diagnosed in 8 dogs. The patients were typically males of large or giant breeds and a wide age range was represented. In all dogs clinical features of acute or chronic cardiac tamponade and right-sided heart failure were present. The pericardial effusion in each case was identified by thoracic radiography, electrocardiography, and echocardiography. Cytologic examination of the fluid did not allow differentiation from hemorrhagic effusions caused by neoplasia. Bacterial and fungal cultures were negative in 5 dogs. In 6 cases, a presumptive diagnosis was based on the absence of cardiac masses on 2-dimensional echocardiography, contrast pericardiography, or both. The condition was managed successfully by partial pericardiectomy in 5 cases. The definitive diagnosis in each case was established by gross cardiac examination at surgery or necropsy and by histologic examination of tissues. Blood vessels and lymphatics of the parietal and visceral pericardia appeared to be the primary targets of the disease process.     

ULTRASONOGRAPHIC APPEARANCE OF JEJUNAL LYMPH NODES IN DOGS WITHOUT CLINICAL SIGNS OF GASTROINTESTINAL DISEASE

The jejunal lymph nodes of 57 dogs without clinical signs of gastrointestinal disease were examined to characterize their ultrasonographic appearance on B-mode and power Doppler examination, and to obtain ultrasonographic measurements. The lymph nodes were mildly hypoechoic to the mesentery in 71% of dogs and isoechoic in 29%. All dogs, 6 years of age or older had jejunal lymph nodes of uniform echogenicity. In dogs less than 6 years of age, nonuniform lymph nodes with different echopatterns were observed. Although most lymph nodes had no blood flow based on power Doppler examination, hilar blood flow was detected in 33% of dogs, which were generally less than 2 years of age. The median maximum thickness of the jejunal lymph nodes was 3.9 mm (range 1.6–8.2 mm), and their median maximum width 7.5 mm (range 2.6–14.7 mm). There was a significant correlation between larger lymph node diameter and younger age and higher body weight. We concluded that patient age should be considered when interpreting the echopattern and vascularity of jejunal lymph nodes in dogs, and that the jejunal lymph nodes of dogs without clinical signs of gastrointestinal disease may exceed the previously stated upper limit of 5–6 mm thickness.     

Ultrasonographic assessment of abdominal lymph nodes in puppies

The jejunal and medial iliac lymph nodes of 53 clinically normal dogs between the age of 4 and 6 weeks were examined ultrasonographically. At least two jejunal and both left and right medial iliac lymph nodes were seen in all dogs. One hundred forty‐five jejunal, 53 right medial iliac and 53 left medial iliac lymph nodes in six litters of dogs, for a total of 251 lymph nodes, were measured for cross sectional maximum diameters. Mean jejunal lymph node length was 16.4 mm (range 6.4–34.9 mm) and mean width was 6.0 mm (range 2.3–15.7 mm). The mean medial iliac lymph node length was 13.6 mm (range 7.2–27.8 mm) and mean width was 4.4 mm (range 1.9–8.2 mm). Significant differences of lymph node size, noted between and within breeds, may not be of clinical significance. The mean size of the combined left and right medial iliac nodes was within previously published ranges for normal adult dogs. Lymph nodes were described in four litters of dogs (162 lymph nodes). Lymph nodes were either uniformly hypoechoic (108/163, 66%) or centrally hyperechoic with a hypoechoic rim (55/163, 34%). Although most (60%) lymph nodes were oval, a variety of shapes were seen, including vermiform and complex branching shapes. We concluded that in 4‐ to 6‐week‐old dogs, medial iliac lymph nodes are similar in size to adult dogs and jejunal lymph nodes are multiple, routinely seen, are larger than in adults and often have unconventional shapes.     

Ultrasonographic diagnosis of unusual portal vascular abnormalities in two cats

Two cases of ascites secondary to portal vascular abnormalities associated with portal hypertension are described. In the first case a five-month-old cat was presented with recurrent ascites and investigations showed that the underlying cause was a hepatic arteriovenous fistula. Ultrasonography showed direct communication of the coeliac artery and right branch of the portal vein. There was also hepatofugal flow in the main portal vein consistent with portal hypertension. The ultrasonographic features were similar to those seen in dogs with hepatic arteriovenous fistulae. In the second case, ascites, portal hypertension and an intraluminal mass in the main portal vein was diagnosed in a 16-year-old cat that had been presented with hyperthyroidism and hepatomegaly. Acquired portosystemic collaterals involving the left renal vein were present. Additional diagnostic investigations were not permitted. Ultrasonography was useful in both cases to document portal hypertension and the underlying cause.     

Two cases of paraprostatic cysts in castrated male dogs

Two castrated male dogs presented for evaluation of tenesmus. Presurgical evaluations included complete physical examinations, serum biochemistry, abdominal ultrasonography, and MRI (case 2 only). Paraprostatic cysts were diagnosed in both cases based on the results of abdominal ultrasonography, MRI, and histopathology of tissue samples obtained during exploratory laparotomy. To the authors' knowledge, the two cases presented herein are the first documented cases of paraprostatic cysts that developed after castration in male dogs. Paraprostatic cysts should be considered in the differential diagnoses for castrated male dogs with prostatic disease.     

Two cases of severe iron-deficiency anaemia due to inflammatory bowel disease in the dog

Two dogs were referred for investigation of lethargy and anaemia. Preliminary examinations by the referring veterinary surgeons had revealed severe anaemia, which was poorly regenerative. In one case, the anaemia was microcytic and, in the other, it was hypochromic. These findings were suggestive of chronic blood loss anaemia. Neither dog had external signs of gastrointestinal disease, although one had vomited on a single occasion during the two weeks preceding referral. Although both dogs were producing grossly normal faeces, further investigations detected faecal occult blood. Multiple full thickness gastrointestinal biopsies were taken at laparotomy. These showed segmental eosinophilic enteritis of the duodenum and proximal jejunum in one case, and marked chronic lymphocytic gastritis in the other. Both cases illustrate the fact that severe systemic disease can result from gastrointestinal pathology in the absence of clinical signs of gastrointestinal disease.     

Electroretinographic changes after intravenous lipid emulsion therapy in a dog and a foal with ivermectin toxicosis

This case report describes ivermectin‐induced blindness in a dog and a foal with normal ophthalmic fundic examinations and attenuated electroretinography (ERG). Subsequent recovery in ERG was noted following intravenous lipid emulsion (ILE) therapy. A dog and a foal were evaluated for ivermectin‐induced blindness. Clinical signs included dull mentation, absent pupillary light reflexes (PLRs), and absent menace on presentation. The animals had normal fundoscopic examinations; however, in both cases ERG was consistent with neurosensory retinal dysfunction. Following ILE therapy for ivermectin toxicosis, return of menace, PLRs, and normal mentation were noted, as was improvement in ERG and serum ivermectin levels. These are the first documented cases of ivermectin‐induced blindness in a dog and a foal with normal fundic examinations and attenuated ERG. ERG improved in both animals after ILE therapy. ERG may assist in the diagnosis of ivermectin toxicosis in dogs and horses. ILE therapy may hasten recovery in treatment of ivermectin‐induced blindness.     

Maxillofacial rhabdomyosarcoma in the canine maxillofacial area

Three dogs had a diagnosis of maxillofacial rhabdomyosarcoma. These dogs were treated with surgery and/or radiotherapy, and had poor clinical responses. The tumor tissues in all three cases were observed around the upper premolar teeth with ulcerative lesions and CT examinations in each case revealed extensive bony involvement into the maxilla. Two cases were subjected to surgical excision of the tissues, followed by an external radiation therapy. The other case was only treated with palliative radiation. Outcomes of the treatment of all the cases were quite poor because of the invasive and refractory nature of the tumor cells, leading to the local recurrence and lung metastasis early in the clinical course. All dogs died within two months of the first admission.     

Management of cervical spondylopathy-associated intervertebral, disc protrusions using metal washers in 78 dogs

Intervertebral 7.5 mm (n = 75) and 6.0 mm (n = 22) metal washers were used to distract intervertebral spaces in 78 consecutive cases of canine cervical spondylopathy-associated disc protrusions, where myelography had demonstrated traction-responsive spinal cord compression. Nineteen dogs had compressive lesions at two sites. Fifty lesions were evaluated myelographically on immediate postoperative radiographs; of these, 32 compressions had been eliminated and 18 had been reduced. Euthanasia was performed in nine dogs within six months of surgery and 15 dogs had varying degrees of neck pain during this period. Long-term follow-up information was available on 65 dogs nine to 70 months following surgery (median 32 months). Sixty-three of these dogs improved postoperatively. Neurological function subsequently deteriorated in 17 dogs 10 to 59 months following surgery (median 34 months). Eight of these 17 cases had further myelographic investigations and all had additional disc protrusions with no evidence of cord compression at the previous sites of surgery. The remaining nine cases had a deterioration in hindlimb function but were not investigated further.     

Observations on the development of congestive heart failure in Irish wolfhounds with dilated cardiomyopathy

Records of previous electrocardiographic (ECG) and echocardiographic examinations of 39 Irish wolfhounds with cardiac failure, obtained during a 10-year survey, were examined to establish whether previously detected abnormalities might be prognostic indicators for the development of congestive heart failure (CHF) due to dilated cardiomyopathy (DCM) in later life. Eighteen dogs (46 per cent) had had atrial fibrillation (AF) at their first examination. Other ECG abnormalities detected at previous examinations were ventricular and supraventricular premature contractions, first and second degree atrioventricular block, P mitrale and left anterior fascicular and right bundle branch blocks. All 39 dogs had developed AF by the time of onset of CHF. The mean age at which CHF was diagnosed was 77 months in males and 86 months in females. The mean age at which AF was first detected was 45 months in males and 59 months in females, and the mean time from the first detection of AF to CHF was 27 months in males and 24 months in females. Previous echocardiographic examinations in eight dogs, over a period of up to five years, revealed progressive left atrial and left ventricular dilatation. Fractional shortening was reduced to below the normal range at the onset of CHF compared with previous examinations in three cases but increased in five. It appears, therefore, that certain ECG abnormalities, especially AF, and/or progressive ventricular and atrial dilatation, may be indicators of 'occult' DCM in wolfhounds.     

Closed reduction of coxofemoral luxation in a goat: case report

Hip luxations have been reported in many ruminants, and several treatments have been described for them. However, successful closed reduction of hip joint luxation has not been reported in goats to date. This case report describes the closed reduction of coxofemoral luxation in a three-month-old male Saanen dairy goat. The goat showed non-weightbearing lameness and abnormal mobility of the proximal right hindlimb. Luxation of the right coxofemoral joint in craniodorsal direction was diagnosed by radiography. The femoral head was repositioned under sedation, and physiotherapy including non-weightbearing hindlimb movement and supported walking exercise was performed. Fifteen days after closed reduction the animal was discharged from the clinic. At that time the animal was sound at a slow walk but lameness was still present at faster gaits. Follow-up examinations revealed normal development of the animal, which subsequently showed no lameness and served successfully as a breeding goat.