Does Dose Matter? Ionizing Radiation Exposure of the Veterinary Patient From Computed Tomography: A Discussion.

Advanced imaging techniques such as computed tomography are commonplace in human medicine and increasingly, are being utilized by the veterinary profession as scanners become more available and affordable. The benefit of computed tomography imaging is the provision of detailed cross-sectional imaging and 3D reconstruction, but this incurs higher doses of ionizing radiation to the patient. This paper reviews risks and effects associated with ionizing radiation, making comparisons to human models, and a hypothetical scenario is discussed using the human risk model for age at time of exposure and increased lifetime risk of cancer with a dog to human year's formula. Various issues are considered with respect to dose reduction, training, equipment and the reported "greater need for guidance and the establishment of best practice" which may lead to future guidance from the International Commission on Radiological Protection.

Clinical progression of cats with early-stage chronic kidney disease fed diets with varying protein and phosphorus contents and calcium to phosphorus ratios.

BACKGROUND: Dietary protein and phosphorus (P) restriction is the mainstay for nutritional management of chronic kidney disease (CKD). However, adequate restriction levels for cats with early CKD remain unclear. OBJECTIVES: To investigate responses in cats with early CKD to varying dietary protein, P, and calcium (Ca) : P ratio. ANIMALS: Nineteen research colony cats with International Renal Interest Society stages 1-2 CKD. METHODS: In an opportunistic longitudinal case study, cats were fed a low protein (59 g/Mcal), low P (0.84 g/Mcal) dry diet (LP-LP; Ca : P = 1.9) for 18 months and later transitioned onto a moderate protein (76-98 g/Mcal), moderate P (1.4-1.6 g/Mcal) dry-wet diet regimen (MP-MP; Ca : P = 1.4-1.6) for 22 months. Fold-changes in serum creatinine, total Ca (tCa) and P (primary outcomes) and fibroblast growth factor 23 (FGF23) were assessed by linear-mixed models. RESULTS: While feeding LP-LP, mean serum creatinine decreased (0.87-fold, 95% confidence interval [CI] 0.81, 0.93, P < .001) to within reference range after 6 months, while increases in total Ca (tCa; 1.16-fold, 95% CI 1.11, 1.22, P < .001) and FGF23 (2.72-fold, 95% CI 1.72, 4.31, P < .001), but not in P (1.03-fold, 95% CI 0.945, 1.124, P = .94), were observed after 17 months. On MP-MP, mean creatinine, tCa and P remained within reference ranges and did not significantly change (P = .11, P = .98, and P = 1, respectively), while FGF23 significantly decreased (0.58-fold, 95% CI 0.36, 0.95, P = .02) after 22 months. CONCLUSIONS AND CLINICAL IMPORTANCE: Cats with early CKD developed hypercalcemia after long-term feeding of a highly P-restricted diet. Increasing dietary P and reducing Ca : P ratio maintained renal markers, while improving Ca-P balance. Cats with early CKD could benefit from moderately protein- and P-restricted diets.

No Observed Adverse Effects on Health Were Detected in Adult Beagle Dogs When Fed a High-Calcium Diet for 40 Weeks.

The implications of long-term high calcium (Ca) intake are well documented in growing dogs and in adult dogs of large breed size, however, the consequences on other breeds and breed sizes are yet to be determined. Eighteen neutered adult beagles, nine males and nine females aged 1.4-4.4 years, were randomized to control or test diets providing in g∙4184 kJ-1 (1000 kcal-1): 1.44 and 7.19 total Ca balanced with 1.05 and 4.25 total phosphorus, respectively, for 40 weeks. Health parameters, ultrasound scans, radiographs, glomerular filtration rate, and mineral balance were measured at eight-week intervals. All dogs remained healthy with no measured evidence of orthopedic, urinary, or renal disease. The test diet resulted in a 5.2 fold increase in fecal Ca excretion. Apparent Ca digestibility (%) and Ca balance (g/d) did not significantly (p > 0.05) change from baseline in the test diet group, although dogs displayed a positive Ca balance (maximum at week 8, 1.11 g/d with 95% CI (0.41, 1.80)) before a neutral Ca balance was restored at week 32. Despite an initial positive Ca balance, we can conclude that no measurable adverse health effects were observed as a result of the test diet fed in this study in beagles over a period of 40 weeks.

Lacrimal bone agenesis in a dog.

A 20-month-old neutered male dachshund dog was referred because of a 10-week history of swelling close to the medial canthus of the left eye. Recurrence of the lesion and cytological appearance of the fluid content were suggestive of inflammation. Computed tomography revealed a triangular-shaped bone defect in the skull deep to the lesion. Computed tomography dacryocystography demonstrated contrast medium pooling within the maxillary recess and nasal cavity rather than filling the lacrimal duct. Lacrimal bone agenesis was diagnosed. Key clinical message: Congenital skull including lacrimal bone agenesis may be responsible for swelling of the medial canthus of the eye and computed tomography dacryocystography is helpful in making a diagnosis.

Agénésie de l'os lacrymal chez un chien. Un teckel mâle castré âgé de 20 mois a été référé en raison d'une histoire de 10 semaines d'enflure près du canthus médial de l'oeil gauche. La récidive de la lésion et l'aspect cytologique du contenu liquidien suggéraient une inflammation. La tomodensitométrie a révélé un défaut osseux de forme triangulaire dans le crâne profondément à la lésion. La dacryocystographie par tomodensitométrie a démontré une accumulation de produit de contraste dans la cavité maxillaire et la cavité nasale plutôt que de remplir le canal lacrymal. Une agénésie de l'os lacrymal a été diagnostiquée.Message clinique clé :Le crâne congénital, y compris l'agénésie de l'os lacrymal, peut être responsable de l'enflure du canthus médial de l'oeil et la dacryocystographie par tomodensitométrie est utile pour poser un diagnostic.(Traduit par Dr Serge Messier).

Gallbladder adenoma in a domestic shorthair cat.

A 13-year-old neutered female domestic shorthair rescue cat presented asymptomatically with raised hepatic enzymes following a routine pre-anaesthetic blood test. Cholangitis was suspected, and supportive treatment with 2 weeks of amoxicillin-clavulanic acid and 4 weeks of ursodeoxycholic acid and S-adenosylmethionine was trialled, with no improvement in biochemistry parameters. Clinicopathological investigations also revealed a markedly raised total bilirubin and abnormal bile acid stimulation test. Abdominal ultrasonography revealed pathological changes in the gallbladder, hepatomegaly with increased echogenicity and markedly thickened common bile duct walls. An exploratory laparotomy was performed revealing a grossly abnormal gallbladder with a small rupture at the dorsal fundus, which was managed via cholecystectomy. Pancreatic and hepatic biopsies were collected concurrently. Histopathology from the submitted samples revealed a gallbladder adenoma, chronic neutrophilic cholangitis and nodular hyperplasia of the pancreas. Culture of the gallbladder bile was negative but may be attributable to the initial treatment with antibiosis. At the time of writing, 5 months postoperatively, the cat had recovered well and remained asymptomatic and clinically healthy, but hepatic enzymes and bilirubin were only mildly reduced from the preoperative levels, despite the cat remaining clinically normal. RELEVANCE AND NOVEL INFORMATION: To our knowledge, this is the first case of a gallbladder adenoma confirmed histopathologically in a feline patient. Our findings suggest that although gallbladder neoplasia is rare in cats, this benign tumour should be considered a differential diagnosis.

A case of an intramural, cavitated feline gastrointestinal eosinophilic sclerosing fibroplasia of the cranial abdomen in a domestic longhair cat.

CASE SUMMARY: A 5-year-old neutered male domestic longhair cat was presented for the investigation of a cranial abdominal mass following a 1-month history of inappetence and lethargy. Abdominal ultrasound revealed a large cavitated mass confluent with the mesenteric aspect of the descending duodenum. At surgery, the mass was found to involve the pylorus, proximal duodenum and pancreas, and was non-resectable. Histopathological examination of surgical biopsies revealed a non-neoplastic process involving eosinophils and fibroplasia. RELEVANCE AND NOVEL INFORMATION: This case report describes an uncommon feline gastrointestinal pathology with an unusual appearance that may provide an additional differential diagnosis other than neoplasia or abdominal abscess when confronted with a cavitated abdominal mass in cats.

Intranasal proliferative fibro-osseous dysplasia in a domestic longhair cat.

CASE SUMMARY: A 13-year-old female domestic longhair cat was presented for further investigation of chronic sneezing combined with a right-sided nasal discharge. A CT scan of the head revealed a locally invasive, aggressive right nasal mass radiographically consistent with a malignant neoplastic process. Histopathology on rhinoscopically guided biopsies revealed an unusual pathology consistent with fibro-osseous hyperplasia/dysplasia. Surgical treatment via a ventral rhinotomy and curettage was performed, and the diagnosis confirmed by repeat histopathology. The cat's clinical signs significantly improved postoperatively. RELEVANCE AND NOVEL INFORMATION: This case report describes an unusual feline nasal pathology. To our knowledge, there are no previous reports of a non-neoplastic, non-inflammatory expansile feline nasal tumour. Also described are the CT and histological appearance of the mass, and the difficulties encountered obtaining the definitive diagnosis. Information regarding the prognosis following surgical removal of proliferative fibro-osseous lesions in cats is poor, especially from the nasal cavity where clean margins may well be impossible to obtain. In this case, surgical resection improved clinical signs and the cat remains well at 15 months post-procedure.

Sterile osteomyelitis in the ulnar diaphysis of a young indoor cat.

CASE SUMMARY: A 3-year-old neutered male indoor British Shorthair cat was referred for a 2-week history of intermittent right forelimb lameness. Radiographic examination showed a diaphyseal monostotic, expansile, fusiform, lytic lesion in the right ulna. CT further defined the lesion and also demonstrated ipsilateral pulmonary consolidation. Histology was conclusive of osteomyelitis, and microbiology and fluorescence in situ hybridisation analysis (FISH) were negative on aerobic and anaerobic bacterial culture, as well as fungal culture. Clinical and radiographic improvement was seen after anti-inflammatory treatment and a short initial period of antibiosis. RELEVANCE AND NOVEL INFORMATION: This is an unusual monostotic diaphyseal cortical location for osteomyelitis in cats and, moreover, may represent a rare case of sterile osteomyelitis. To our knowledge, non-traumatic osteomyelitis in this location in cats has not been reported in the veterinary literature.

Effects of the long-term feeding of diets enriched with inorganic phosphorus on the adult feline kidney and phosphorus metabolism.

Renal disease has a high incidence in cats, and some evidence implicates dietary P as well. To investigate this further, two studies in healthy adult cats were conducted. Study 1 (36 weeks) included forty-eight cats, stratified to control or test diets providing 1·2 or 4·8 g/1000 kcal (4184 kJ) P (0 or approximately 3·6 g/1000 kcal (4184 kJ) inorganic P, Ca:P 1·2, 0·6). Study 2 (29 weeks) included fifty cats, stratified to control or test diets, providing 1·3 or 3·6 g/1000 kcal (4184 kJ) P (0 or approximately 1·5 g/1000 kcal (4184 kJ) inorganic P, Ca:P 1·2, 0·9). Health markers, glomerular filtration rate (GFR) and mineral balance were measured regularly, with abdominal ultrasound. Study 1 was halted after 4 weeks as the test group GFR reduced by 0·4 (95 % CI 0·3, 0·5) ml/min per kg, and ultrasound revealed changes in renal echogenicity. In study 2, at week 28, no change in mean GFR was observed (P >0·05); however, altered renal echogenicity was detected in 36 % of test cats. In agreement with previous studies, feeding a diet with Ca:P <1·0, a high total and inorganic P inclusion resulted in loss of renal function and changes in echogenicity suggestive of renal pathology. Feeding a diet containing lower total and inorganic P with Ca:P close to 1·0 led to more subtle structural changes in a third of test cats; however, nephrolithiasis occurred in both diet groups, complicating data interpretation. We conclude that the no observed adverse effects level for total dietary P in adult cats is lower than 3·6 g/1000 kcal (4184 kJ), however the effect of inorganic P sources and Ca:P require further investigation.

Adult dogs are capable of regulating calcium balance, with no adverse effects on health, when fed a high-calcium diet.

Although the implications of long-term high Ca intakes have been well documented in growing dogs, the health consequences of Ca excess in adult dogs remain to be established. To evaluate the impact of feeding a diet containing 7·1 g/4184 kJ (1000 kcal) Ca for 40 weeks on Ca balance and health parameters in adult dogs, eighteen neutered adult Labrador Retrievers, (nine males and nine females) aged 2·5-7·4 years were randomised to one of two customised diets for 40 weeks. The diets were manufactured according to similar nutritional specifications, with the exception of Ca and P levels. The diets provided 1·7 and 7·1 g/4184 kJ (1000 kcal) (200(SD26) and 881(SD145) mg/kg body weight0·75 per d, respectively) Ca, respectively, with a Ca:P ratio of 1·6. Clinical examinations, ultrasound scans, radiographs, health parameters, metabolic effects and mineral balance were recorded at baseline and at 8-week intervals throughout the study. Dogs in both groups were healthy throughout the trial without evidence of urinary, renal or orthopaedic disease. In addition, there were no clinically relevant changes in any of the measures made in either group (all P>0·05). The high-Ca diet resulted in a 3·3-fold increase in faecal Ca excretion (P0·05). Ca intakes of up to 7·1 g/4184 kJ (1000 kcal) are well tolerated over a period of 40 weeks, with no adverse effects that could be attributed to the diet or to a high mineral intake.

Congenital Extrahepatic Abdominal Arteriovenous Fistula and Apparent Patent Ductus Venosus in a Dog.

A 3 mo old male German shepherd dog presented with a 2 wk history of diarrhea with possible melena followed by inappetence and progressive abdominal distension. Clinical findings, serum biochemical analysis, and abdominal ultrasound were highly suggestive of an extrahepatic abdominal arteriovenous fistula and concurrent patent ductus venosus, which were confirmed during an abdominal exploratory surgery. Renal biopsies taken at the time of surgery confirmed a chronic glomerulopathy. The dog made a good initial recovery from the procedure but was euthanatized 6 wk postoperatively for medically unresponsive renal disease.

Radiographic and ultrasonographic features of canine paraprostatic cysts.

Mineralization of paraprostatic cysts is reported to be uncommon. This retrospective study was performed to review the imaging findings of eight histologically confirmed canine paraprostatic cysts. Radiographic patterns of mineralization seen are described. Four of the eight dogs had mineralized cysts. Mineralization seen on radiography was not consistently seen on ultrasonography, probably due to the lack of acoustic shadowing artefact from the small depth of mineralized tissue. It is thus concluded that mineralization of paraprostatic cysts is more common than implied in the literature, and that radiography is superior to ultrasonography in identifying its presence.