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  • Author or Editor: Allison L. Zwingenberger x
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Abstract

Objective—To compare hepatic, pancreatic, and gastric perfusion on dynamic computed tomography (CT) scans of clinically normal dogs with those of dogs with portal vascular anomalies.

Sample Population—Dynamic computed tomography (CT) scans of 10 clinically normal dogs and 21 dogs with portal vascular anomalies.

Procedures—Retrospective analysis of dynamic CT scans. Hepatic arterial perfusion, hepatic portal perfusion, total hepatic perfusion, hepatic perfusion index, gastric perfusion, and pancreatic perfusion were calculated from time attenuation curves.

Results—Mean ± hepatic arterial perfusion was significantly higher in affected dogs (0.57 ± 0.27 mL/min•mL−1) than in clinically normal dogs (0.23 ± 0.11 mL/min•mL−1), and hepatic portal perfusion was significantly lower in affected dogs (0.52 ± 0.47 mL/min•mL−1) than in clinically normal dogs (1.08 ± 0.45 mL/min•mL−1). This was reflected in the hepatic perfusion index, which was significantly higher in affected dogs (0.59 ± 0.34), compared with clinically normal dogs (0.19 ± 0.07). Gastric perfusion was significantly higher in dogs with portal vascular anomalies (0.72 ± 0.44 mL/min•mL−1) than in clinically normal dogs (0.41 ± 0.21 mL/min•mL−1), but total hepatic perfusion and pancreatic perfusion were not significantly different. Among subgroups, dogs with congenital intrahepatic portosystemic shunts and dogs with arterioportal fistulae had higher hepatic arterial perfusion than did clinically normal dogs. Dogs with congenital intrahepatic portosystemic shunts also had an increase in gastric perfusion and hepatic perfusion index.

Conclusions and Clinical Relevance—Hepatic perfusion variables measured on CT scans revealed differences in hemodynamics between clinically normal dogs and those with portal vascular anomalies.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine which organs can be reliably visualized ultrasonographically in bearded dragons (Pogona vitticeps), describe their normal ultrasonographic appearance, and describe an ultrasonographic technique for use with this species.

Design—Cross-sectional study.

Animals—14 healthy bearded dragons (6 females and 8 males).

Procedures—Bearded dragons were manually restrained in dorsal and sternal recumbency, and coelomic organs were evaluated by use of linear 7- to 15-MHz and microconvex 5- to 8-MHz transducers. Visibility, size, echogenicity, and ultrasound transducer position were assessed for each organ.

Results—Coelomic ultrasonography with both microconvex and linear ultrasound transducers allowed for visualization of the heart, pleural surface of the lungs, liver, caudal vena cava, aorta, ventral abdominal vein, gallbladder, fat bodies, gastric fundus, cecum, colon, cloaca, kidneys, and testes or ovaries in all animals. The pylorus was visualized in 12 of 14 animals. The small intestinal loops were visualized in 12 of 14 animals with the linear transducer, but could not be reliably identified with the microconvex transducer. The hemipenes were visualized in 7 of 8 males. The adrenal glands and spleen were not identified in any animal. Anechoic free coelomic fluid was present in 11 of 14 animals. Heart width, heart length, ventricular wall thickness, gastric fundus wall thickness, and height of the caudal poles of the kidneys were positively associated with body weight. Testis width was negatively associated with body weight in males.

Conclusions and Clinical Relevance—Results indicated coelomic ultrasonography is a potentially valuable imaging modality for assessment of most organs in bearded dragons and can be performed in unsedated animals.

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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To perform qualitative and quantitative analysis of positron emission tomography (PET)/CT images using spontaneous ventilation (SV) and positive-pressure breath-hold (PPBH) techniques in order to demonstrate the feasibility of PPBH PET/CT to decrease respiration-induced artifacts.

ANIMALS

5 healthy female mixed-breed dogs.

PROCEDURES

2-([18F]fluoro)-2-deoxy-D-glucose (was administered to each anesthetized dog. An SV PET/CT scan was performed from the head to the femur using 8 bed positions (3 min/bed) followed by a PPBH scan centered over the diaphragm with a single bed position (1.5 min/bed). PET image quality, the misalignment of organs between PET and CT images, and standardized uptake values (SUVs) of liver adjacent to diaphragm were compared between SV and PPBH.

RESULTS

Overall image quality and conspicuity of anatomic structures were superior in PPBH than in SV PET images. PPBH induced significantly less misalignment of the liver and diaphragm in all planes compared to SV. For the gall bladder, PPBH showed significantly less misalignment than SV only in the transverse plane. The maximum SUV in all of the liver areas was significantly higher with PPBH compared to SV. PPBH exhibited significantly higher mean SUV in the liver adjacent to the left diaphragmatic dome and left lateral border and higher minimum SUV only in the liver adjacent to the left diaphragmatic dome.

CLINICAL RELEVANCE

PPBH was demonstrated to be a feasible PET/CT protocol with higher PET image quality, less organ misalignment on fused PET/CT, and more accurate SUVs of the liver compared to SV PET/CT in healthy dogs.

Full access
in American Journal of Veterinary Research

Abstract

CASE DESCRIPTION

4 cats (6 to 9 months old) were evaluated because of clinical signs consistent with a portosystemic shunt (PSS).

CLINICAL FINDINGS

Among the 4 cats, 3 had neurologic abnormalities including ataxia, head pressing, disorientation, and obtundation. One cat was evaluated because of urethral obstruction; a retrieved urethral stone was determined to have urate composition. Clinicopathologic findings (hypoproteinemia, low BUN concentration, and high serum bile acids concentration) were consistent with a PSS in all cats. A diagnosis of intrahepatic PSS (IHPSS) was made for all cats on the basis of ultrasonographic and CT findings.

TREATMENT AND OUTCOME

All cats underwent percutaneous transvenous coil embolization (PTCE). No major intraprocedural complications were encountered, and all cats were discharged from the hospital. For the 3 cats that were presented with neurologic signs, an evaluation performed at 12, 14, or 48 months after the procedure revealed resolution of the neurologic signs, and owners reported that the behavior of each cat appeared normal. One cat that initially had neurologic and gastrointestinal signs had lower urinary tract signs after PTCE and developed an acquired extrahepatic PSS.

CLINICAL RELEVANCE

Although IHPSSs in cats are uncommon, the outcomes of PTCE for the 4 cats of the present report suggested that this treatment may benefit cats with an IHPSS. No short-term complications were encountered, and all cats had improvement in clinical signs following PTCE, although an acquired extrahepatic PSS was later identified in 1 cat. Further investigation of the use of endovascular techniques for the treatment of IHPSSs in cats and other species is warranted.

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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To characterize the extent and location of atelectasis in healthy anesthetized dogs positioned in lateral recumbency and to determine whether repositioning dogs in sternal recumbency would resolve atelectasis.

ANIMALS 6 healthy adult Beagles.

PROCEDURES Each dog was anesthetized and underwent a CT examination twice with a 2-week interval between examinations. Once anesthetized, each dog was positioned in sternal recumbency, and a breath-hold helical transverse thoracic CT scan was acquired. The dog was then positioned in lateral recumbency for 30 minutes, and images were obtained at 5 preselected sites at 3, 8, 13, 20, and 30 minutes after repositioning (phase 1). Then, the dog was repositioned in sternal recumbency, and CT images were obtained at the 5 preselected sites at 5, 10, and 20 minutes after repositioning (phase 2). The protocol for the second examination was the same as the first except the dog was positioned in the opposite lateral recumbency during phase 1. The attenuation and cross-sectional area of the lung lobes at the preselected sites were measured and compared over time.

RESULTS Lateral recumbency did not cause atelectasis in any of the dogs. Patchy areas of abnormally increased attenuation were infrequently detected in the left cranial lung lobe when dogs were positioned in left lateral recumbency, and those areas failed to resolve when dogs were positioned in sternal recumbency.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the extent of lung attenuation changes was minimal in healthy anesthetized Beagles positioned in lateral recumbency and should not preclude CT examination.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To determine whether extent of collateral circulation would change during temporary occlusion of the caudal vena cava (CVC) in ferrets (Mustela putorius), a pressure change would occur caudal to the occlusion, and differences would exist between the sexes with respect to those changes.

ANIMALS 8 adult ferrets (4 castrated males and 4 spayed females).

PROCEDURES Ferrets were anesthetized. A balloon occlusion catheter was introduced through a jugular vein, passed into the CVC by use of fluoroscopy, positioned cranial to the right renal vein, and inflated for 20 minutes. Venography was performed 5 and 15 minutes after occlusion. Pressure in the CVC caudal to the occlusion was measured continuously. A CBC, plasma biochemical analysis, and urinalysis were performed immediately after the procedure and 2 or 3 days later.

RESULTS All 8 ferrets survived the procedure; no differences were apparent between the sexes. Vessels providing collateral circulation were identified in all ferrets, indicating blood flow to the paravertebral venous plexus. Complications observed prior to occlusion included atrial and ventricular premature contractions. Complications after occlusion included bradycardia, seizures, and extravasation of contrast medium. Mean baseline CVC pressure was 5.4 cm H2O. During occlusion, 6 ferrets had a moderate increase in CVC pressure (mean, 24.3 cm H2O) and 2 ferrets had a marked increase in CVC pressure to > 55.0 cm H2O.

CONCLUSIONS AND CLINICAL RELEVANCE Caval occlusion for 20 minutes was performed in healthy ferrets with minimal adverse effects noted within the follow-up period and no apparent differences between sexes. The CVC pressure during occlusion may be prognostic in ferrets undergoing surgical ligation of the CVC, which commonly occurs during adrenal tumor resection.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To describe clinical and diagnostic imaging features of zygomatic sialadenitis in dogs.

Design—Retrospective case series.

Animals—11 dogs with zygomatic sialadenitis and 20 control dogs without evidence of retrobulbar disease.

Procedures—Medical records were searched for dogs with zygomatic sialadenitis that underwent some combination of magnetic resonance imaging (MRI), computed tomography (CT), and ultrasonography. Signalment, clinical signs, results of clinicopathologic tests, cytologic and histologic diagnosis, treatment, qualitative disease features, and disease course were recorded. Images obtained via MRI or CT were analyzed for pre- and postcontrast signal intensity or density, respectively; zygomatic salivary gland area was determined. Results were compared with those of control dogs that underwent the same imaging procedures (n = 10/method). Ultrasonographic images of affected dogs were assessed qualitatively.

Results—Most (9/11) affected dogs were medium- or large-breed males (mean age, 8 years) with unilateral disease. Affected dogs had clinical signs of retrobulbar disease and cytologic or histologic evidence of zygomatic sialadenitis. Sialoceles were detected in 7 affected glands. Compared with values for control dogs, MRI findings in affected dogs (n = 7) included gland enlargement, T1-weighted hypointensity, T2-weighted hyperintensity, and increased contrast enhancement; CT features in affected dogs (2) included gland enlargement and hypodensity on unenhanced images. Retrobulbar masses were identified via ultrasonography in 9 of 10 orbits examined, and zygomatic salivary gland origin was detected in 4.

Conclusions and Clinical Relevance—Visualization of anatomic structures for diagnosis of zygomatic sialadenitis and evaluation of adjacent structures was excellent via MRI and CT Ultrasonography was less definitive but useful for sample collection.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the sensitivity, positive predictive value, and interobserver variability of CT in the detection of bullae associated with spontaneous pneumothorax in dogs.

Design—Retrospective case series.

Animals—19 dogs with spontaneous pneumothorax caused by rupture of bullae.

Procedures—Dogs that had CT for spontaneous pneumothorax caused by rupture of bullae confirmed at surgery (median sternotomy) or necropsy were included. Patient signalment, CT protocols, and bulla location, size, and number were obtained from the medical records. Computed tomographic images were reviewed by 3 board-certified radiologists who reported on the location, size, and number of bullae as well as the subjective severity of pneumothorax.

Results—Sensitivities of the 3 readers for bulla detection were 42.3%, 57.7%, and 57.7%, with positive predictive values of 52.4%, 14.2%, and 8.4%, respectively, with the latter 2 readers having a high rate of false-positive diagnoses. There was good interobserver agreement (κ = 0.640) for correct identification of bullae. Increasing size of the bulla was significantly associated with a correct CT diagnosis in 1 reader but not in the other 2 readers. Correct diagnosis was not associated with slice thickness, ventilation protocol, or degree of pneumothorax.

Conclusions and Clinical Relevance—Sensitivity and positive predictive value of CT for bulla detection were low. Results suggested that CT is potentially an ineffective preoperative diagnostic technique in dogs with spontaneous pneumothorax caused by bulla rupture because lesions can be missed or incorrectly diagnosed. Bulla size may affect visibility on CT.

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in Journal of the American Veterinary Medical Association

Abstract

CASE DESCRIPTION

A 14-year-old 120-kg (264-lb) sexually intact male Sumatran tiger (Panthera tigris sumatrae) and its 10-year-old 130-kg (286-lb) sexually intact male offspring were housed separately and evaluated independently after experiencing weeks of ongoing malaise, weight loss, and anorexia.

CLINICAL FINDINGS

Both animals were immobilized and anesthetized for physical examinations and diagnostic testing. Complete blood counts revealed leukopenia and anemia in both tigers. Splenomegaly was identified on abdominal ultrasonography. Cytologic examination and immunohistochemical staining of splenic samples confirmed intermediate to large B-cell lymphoma; no evidence of lymphoma in surrounding organs was noted.

TREATMENT AND OUTCOME

The sire was treated with lomustine and prednisolone. This tiger was euthanized 21 months after initiation of treatment because of chronic progressive renal disease. The male offspring was treated with l-asparaginase but did not respond to the treatment. A splenectomy was performed, and malaise and anorexia resolved. No further chemotherapy was administered, and the male offspring was instead maintained on a low dose of prednisolone. Thirty-two months after diagnosis, the male offspring was still considered to be in remission.

CLINICAL RELEVANCE

To our knowledge, this was the first known report of the diagnosis and management of a splenic B-cell lymphoma in a tiger. Both tigers achieved positive clinical responses and long-term survival by means of different treatment modalities. The finding of such an unusual neoplasm in a male tiger and its male offspring was noteworthy, raising the possibility of a genetic predisposition for this lymphoma type.

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in Journal of the American Veterinary Medical Association