Sarah Nemanic

Characterization, treatment, and outcome of bacterial cholecystitis and bactibilia in dogs

Objective-To characterize historical, clinicopathologic, ultrasonographic, microbiological, surgical, and histopathologic features of bacterial cholecystitis and bactibilia in dogs and evaluate response to treatment and outcomes in these patients. Design-Retrospective case-control study. Animals-40 client-owned dogs (10 with bacterial cholecystitis on histologic analysis or bactibilia on cytologic examination [case dogs] and 30 without bactibilia [controls]) evaluated at a veterinary teaching hospital between 2010 and 2014. Procedures-Signalment, history, clinicopathologic findings, ultrasonographic features, microbiological results, surgical findings, histopathologic changes, treatments, and outcomes of case dogs were derived from medical records and summarized. Demographic and clinicopathologic data and ultrasonographic findings were compared between case and control dogs. Relationships among prior antimicrobial treatment, sediment formation in the gallbladder, presence of immobile biliary sludge, and presence of bactibilia or bacterial cholecystitis were assessed. Results-No finding was pathognomonic for bactibilia or bacterial cholecystitis in dogs. Case dogs were significantly more likely to have immobile biliary sludge and had a greater degree of biliary sediment formation than did control dogs. All case dogs for which gallbladders were examined histologically (6/6) had bacterial cholecystitis. Five of 10 case dogs were Dachshunds. Medical or surgical treatment resulted in good outcomes. Conclusions and Clinical Relevance-Bactibilia and bacterial cholecystitis were important differential diagnoses in dogs with signs referable to biliary tract disease. Dachshunds were overrepresented, which may suggest a breed predisposition. Cytologic evaluation of bile should be considered in the routine assessment of dogs with hepatobiliary disease if immobile biliary sludge is present. (J Am Vet Med Assoc 2015;246:982-989).

In vitro evaluation of a novel fiducial marker for computed tomography and magnetic resonance imaging of soft tissues in small animals

OBJECTIVE To construct and optimize a fiducial marker suitable for both CT and MRI. SAMPLE Fiducial markers containing serial dilutions of iopamidol mixed with water. PROCEDURES IV tubing sets were infused with serial dilutions (0% to 100%; increments of 10%) of iopamidol. Tubing ends were sealed; additional seals were added to create an equilateral triangle. A reference point was created by placing a crimp in 1 side. Markers were fixed to a gelatin soft tissue-attenuating phantom and evaluated by use of CT and MRI. For CT, simple linear regression analysis was used to assess the relationship between the percentage of marker contrast medium and quantitative variables, including marker attenuation, attenuation changes in the phantom, and beam-hardening artifact length. A subjective grading scheme for artifact creation on CT images and marker visibility on MRI images was used. Measurements were obtained by investigators who were unaware of the contents of each marker. RESULTS Percentage of contrast medium in each marker was strongly correlated with marker attenuation (r(2) = 0.96), artifact length (r(2) = 0.765), and mean attenuation changes within the phantom (r(2) = 0.826) for CT. Subjective CT scores indicated that concentrations of contrast medium > 50% resulted in excessive artifacts. Markers with concentrations of iopamidol > 50% had poor subjective MRI visibility scores. No artifacts were seen on MRI. CONCLUSIONS AND CLINICAL RELEVANCE A marker containing a 10% solution of iodinated contrast medium mixed with water provided ideal contrast for both CT and MRI.

Use of computed tomography to compare two femoral head and neck excision ostectomy techniques as performed by two novice veterinarians.

OBJECTIVES To compare the results of femoral head and neck excision (FHNE) ostectomy performed by two novice veterinarians using an osteotome and mallet or microsagittal saw. METHODS In this ex vivo cadaveric study, hindlimbs of eight canine cadavers were randomized to FHNE with osteotome or micro sagittal saw as performed by two recently graduated veterinarians. The hindimbs were imaged by computed tomography (CT) before and after the osteotomy. Post FHNE CT images were evaluated by a board certified radiologist blinded to the ostectomy technique for assessment of the number of bone fragments, fissures, smoothness of osteotomy margination, and volume of residual femoral neck. RESULTS Femoral head and neck excision performed with the osteotome produced more peri-ostectomy bone fragments, cortical fissures, irregular margins, and residual femoral neck volume, compared with osteotomy using a saw. CLINICAL RELEVANCE Compared to FHNE performed with a sagittal saw, osteotome FHNE resulted in a greater bone trauma and residual neck bone volume, which would require post-ostectomy modification in a clinical setting.

Augmentation of diaphyseal fractures of the radius and ulna in toy breed dogs using a free autogenous omental graft and bone plating

OBJECTIVES Evaluation of the short-term outcome, duration of bone healing, and complications following bone plate fixation in dogs weighing ≤6 kg, with and without the use of a free autogenous greater omental graft (OG). MATERIALS AND METHODS A retrospective clinical study reviewed the medical records of 25 dogs of body weight <6 kg with mid to distal diaphyseal fractures of the radius and ulna (29 fractures) treated with open reduction bone plate fixation. Thirteen out of 29 fractures were implanted with an additional 2-3 cm³ OG lateral, cranial, and medial to the fracture site, adjacent to the bone plate. RESULTS Median time to radiographic healing in OG fractures (n = 11) was 70 days (range 28-98) compared to 106 days (range: 56-144) in non-OG grafted fractures (n = 14). The OG dogs had no major complications; minor complications included oedema, erythema, and mild osteopenia. Six of the eight non-OG dogs for which follow-up could be obtained developed osteopenia necessitating implant removal, four of which re-fractured the radius one to five months after implant removal, with one dog re-fracturing the limb a second time and resulting in amputation. Telephone follow-up of owners of OG dogs (n = 11) three to 15 months (median 10) post-surgery did not identify any signs of lameness or other complications. Owners of the non-OG dogs (n = 8) reported that there were not any signs of lameness six to 48 months (median 36) post-surgery. CLINICAL RELEVANCE Free autogenous omental grafting of diaphyseal fractures of the radius and ulna was associated with radial and ulnar healing with minimal complications in dogs weighing less than 6 kg.

COMBINATION OF COMPUTED TOMOGRAPHIC IMAGING CHARACTERISTICS OF MEDIAL RETROPHARYNGEAL LYMPH NODES AND NASAL PASSAGES AIDS DISCRIMINATION BETWEEN RHINITIS AND NEOPLASIA IN CATS

Feline nasal diseases are a diagnostic challenge. The objective of this retrospective, cross-sectional study was to determine whether computed tomography (CT) imaging characteristics of the medial retropharyngeal lymph nodes (MRPLN), alone or in combination with CT imaging characteristics of the nasal passages, could aid in differentiation between rhinitis and nasal neoplasia. Cats were recruited from record archives at two veterinary facilities during the period of 2008-2012. Selection criteria were presentation for chronic nasal discharge, contrast-enhanced CT of the head that included the MRPLN, and rhinoscopic nasal biopsy resulting in diagnosis of rhinitis or neoplasia. For each CT scan, two board-certified veterinary radiologists recorded MRPLN size, attenuation, heterogeneity, contrast-medium enhancement, margination, shape, presence of a lymph node hilus, perinodal fat, turbinate lysis, paranasal bone lysis, and nasal mass. Both readers were unaware of patient information at the time of CT interpretation. Thirty-four cats with rhinitis and 22 cats with neoplasia were included. Computed tomographic characteristics significantly associated with neoplasia included abnormal MRPLN hilus (OR 5.1), paranasal bone lysis (OR 5.6), turbinate lysis (5.6), mass (OR 26.1), MRPLN height asymmetry (OR 4.5), and decreased MRPLN precontrast heterogeneity (OR 7.0). The combined features predictive of neoplasia were a nasal mass with abnormal hilus (OR 47.7); lysis of turbinates/paranasal bones with abnormal MRPLN hilus (OR 16.2). Findings supported the hypothesis that combining CT features of the nasal passages and MRPLN aided in differentiating rhinitis from neoplasia in cats.

Use of Multidetector Computed Tomography in the Assessment of Dogs with Pericardial Effusion

Background Contrast‐enhanced multidetector computed tomography (MDCT) allows high spatial and temporal resolution imaging of cardiac, thoracic, and abdominal structures. Accurate determination of the cause of pericardial effusion (PE) is essential to providing appropriate treatment and prognosis. Echocardiography and pericardial fluid analysis may not differentiate between causes of PE and cannot identify extracardiac metastasis. Hypothesis/Objectives Describe the thoracic and abdominal MDCT findings and evaluate the utility of MDCT to differentiate between neoplastic and nonneoplastic causes of PE in dogs. Animals Eleven client‐owned dogs with PE diagnosed by echocardiography. Methods Prospective observational study. Transthoracic echocardiography (TTE), 3‐view thoracic radiography, and contrast‐enhanced thoracic and abdominal MDCT images were evaluated for the presence of cardiac masses, pulmonary metastases, and abdominal masses. Histopathology in 5 dogs and survival analysis in all dogs were evaluated. Results A neoplastic cause was identified in 6/11 dogs and a nonneoplastic cause was identified in 5/11. Cardiac MDCT findings were consistent with TTE findings in all dogs with right atrial (5/5) and heart base masses (1/1). Pulmonary metastases were identified in 1/11 dogs by thoracic radiography and in 2/11 dogs by MDCT. MDCT identified splenic or hepatic lesions consistent with neoplasia in 6/11 and 5/11 dogs, respectively. Focal MDCT pericardial changes at the pericardiocentesis site were noted in 3/11 dogs. Conclusions and Clinical Importance Multidetector computed tomography did not improve the detection of cardiac masses in dogs with PE over echocardiography. The benefit of MDCT was primarily in the detection of pulmonary metastases and extracardiac lesions using a single imaging modality.

Ultrasonography and noncontrast computed tomography of medial retropharyngeal lymph nodes in healthy cats.

OBJECTIVE To determine various measurements of medial retropharyngeal lymph nodes (MRPLNs) in healthy cats via ultrasonography and CT. ANIMALS 45 cats (age range, 2 to 8 years). PROCEDURES Cats underwent CT of the head and ultrasonography of the cervical region. Various measurements of MRPLNs were obtained, and parenchymal heterogeneity, presence of a hilus, appearance of margins, and attenuation of MRPLNs were determined. RESULTS Data for 7 cats were excluded because they did not meet inclusion criteria; data for 38 cats were evaluated. Measurements of left and right MRPLNs were not significantly different. Mean length × rostral height × rostral width dimensions of MRPLNs were 20.7 × 12.4 × 3.7 mm and 20.7 × 13.1 × 4.7 mm in ultrasonographic and CT images, respectively. Maximum MRPLN dimensions were approximately 32 × 20 × 7 mm. Mean attenuation of MRPLNs was 40.2 Hounsfield units. Parenchyma of MRPLNs was mildly (via CT) to moderately (via ultrasonography) heterogeneous. A hilus was identified in 95% (via ultrasonography) and 24% or 92% (via CT [depending on criteria used to define a hilus]) of MPRLNs. Lymph node margins were smooth in CT images and mildly irregular in ultrasonographic images. A negative linear correlation was detected between age of cat and MRPLN volume. CONCLUSIONS AND CLINICAL RELEVANCE MRPLNs in cats were easily imaged via ultrasonography and CT. Left and right MRPLNs were symmetric, and MRPLNs were larger in young adult cats versus old cats. Data were intended to serve as references for evaluation of MRPLNs in healthy cats.

Quantification of surgical margin length changes after excision of feline injection site sarcomas—A pilot study

OBJECTIVE To evaluate degree length change of lateral surgical margins at various stages of processing for histological examination and quantify the length change between grossly normal surgical margins (GNSM) and pathologist-reported histologic tumor-free margin (HTFM) in widely resected feline injection site sarcoma (FISS) specimens. STUDY DESIGN Prospective clinical study. ANIMALS Five client-owned cats with injection site sarcomas. METHODS All cats underwent wide surgical excision (35-55 mm gross lateral margins, 2 fascial planes deep). Gross normal lateral margin measurements from tumor edge were recorded in 4 directions (cranial, caudal, dorsal, ventral) at 5 time points: intra-op (in vivo GNSM); immediately following excision (ex vivo GNSM); following formalin fixation (post-fixation GNSM); after trimming and mounting on glass slides (on-slide GNSM); and HTFM at the narrowest point from the HTFM from the same slides used for on-slide GNSM. Percent change in lateral margin length from in vivo measurements was quantified at each time point and compared using 1-way repeated measures ANOVA. RESULTS The largest mean decrease in percent GNSM length occurred immediately after excision (in vivo to ex vivo GNSM = 29%; P = .016). Formalin fixation, trimming, and mounting on slides did not result in additional significant changes in length. Mean HTFM length was significantly decreased compared to both in vivo GNSM (33%; P = .014) and on-slide GNSM (7%; P = .024). CONCLUSION Significant decreases in surgical margin length in FISS specimens occur immediately following excision (prior to formalin fixation). Subgross evaluation of tumor-free margins from on-slide GNSM to HTFM overestimates the actual (histologic) tumor-free margins.

Comparison of 2 fluid ingress/egress systems for canine stifle arthroscopy using computed tomography.

OBJECTIVE To evaluate volume of extra-articular fluid egress and complications associated with 2 fluid ingress/egress techniques for stifle arthroscopy. STUDY DESIGN Ex vivo study. STUDY SUBJECTS Canine cadavers (n = 14). METHODS Four cadavers (8 stifles) were used to validate 3D computed tomographic (CT) methods to quantify stifle joint intra- and extra-articular volumes of iodinated contrast medium. Ten canine cadavers (20 stifles) had preoperative CT, followed by stifle arthroscopy using a 10% solution of iodinated contrast enhanced ingress fluid delivered by pressure bag (2PB) or by arthroscopic peristaltic pump (3FP). All 3FP limbs had an additional fluid egress portal placed by cannula and obturator. Arthroscopy was limited to 20 minutes/joint. The volume of the contrast medium egress into the soft tissues was measured on postoperative 3D CT reconstructed images. RESULTS Mean percentage of total ingress fluids administered that remained in the joint and extra-articular tissues postoperatively was 8.8 ± 1.2% in 3FP and 33.2 ± 8% in 2PB (P = .014). Two 3FP joints had 4-5 mm egress obturator tracks on the proximal medial trochlear ridge. Two 2PB joints had severe joint collapse from extracapsular fluid precluding further examination. Intermittent visual blurring by joint fluid mixing or fat pad fragmentation/dissolution was noted in 2PB joints. CONCLUSIONS A superior technique was not identified: 2PB had greater egress fluid tissue accumulation, whereas 3FP had better viewing of intra-articular structures with less tissue egress fluid accumulation; however, cartilage damage was induced with the egress obturator.Objective To evaluate volume of extra-articular fluid egress and complications associated with 2 fluid ingress/egress techniques for stifle arthroscopy. Study Design Ex vivo study. Study Subjects Canine cadavers (n = 14). Methods Four cadavers (8 stifles) were used to validate 3D computed tomographic (CT) methods to quantify stifle joint intra- and extra-articular volumes of iodinated contrast medium. Ten canine cadavers (20 stifles) had preoperative CT, followed by stifle arthroscopy using a 10% solution of iodinated contrast enhanced ingress fluid delivered by pressure bag (2PB) or by arthroscopic peristaltic pump (3FP). All 3FP limbs had an additional fluid egress portal placed by cannula and obturator. Arthroscopy was limited to 20 minutes/joint. The volume of the contrast medium egress into the soft tissues was measured on postoperative 3D CT reconstructed images. Results Mean percentage of total ingress fluids administered that remained in the joint and extra-articular tissues postoperatively was 8.8 ± 1.2% in 3FP and 33.2 ± 8% in 2PB (P = .014). Two 3FP joints had 4–5 mm egress obturator tracks on the proximal medial trochlear ridge. Two 2PB joints had severe joint collapse from extracapsular fluid precluding further examination. Intermittent visual blurring by joint fluid mixing or fat pad fragmentation/dissolution was noted in 2PB joints. Conclusions A superior technique was not identified: 2PB had greater egress fluid tissue accumulation, whereas 3FP had better viewing of intra-articular structures with less tissue egress fluid accumulation; however, cartilage damage was induced with the egress obturator.

Computed tomographic assessment of sternal lymph node dimensions and attenuation in healthy dogs

OBJECTIVE To assess dimensions and attenuation of sternal lymph nodes (SLNs) observed by means of CT in healthy dogs. ANIMALS 12 healthy adult research dogs. PROCEDURES Precontrast and postcontrast enhanced CT of the thorax was performed on each dog. Objective and subjective contrast-enhanced CT measurements were obtained. RESULTS By use of CT, 2 SLNs were identified in 10 of the 12 dogs and 1 SLN was identified in 2. Median SLN length, height, and width were 8.5 mm (range, 4 to 22 mm), 6.0 mm (range, 3 to 10 mm), and 5.0 mm (range, 3 to 10 mm), respectively. Median SLN length-to-T4 ratio, height-to-T4 ratio, and width-to-T4 ratio were 0.64 (range, 0.24 to 1.22), 0.37 (range, 0.25 to 0.53), and 0.29 (range, 0.19 to 0.67), respectively. Median SLN volume was 123 mm3 (range, 38 to 484 mm3). Median height-to-length ratio, width-to-length ratio, and height-to-width ratio were 0.57 (range, 0.27 to 1.75), 0.51 (range, 0.31 to 1.25), and 1.27 (range, 0.50 to 2.50), respectively. All SLNs had homogenous contrast enhancement with median precontrast and postcontrast attenuation values of 18.3 Hounsfield units (HU; range, 4.4 to 36.9 HU) and 41.3 HU (range, 24.0 to 77.4 HU), respectively. All SLNs had a visible hilus, which was fat attenuating in 8 dogs and hypoattenuating in 4 dogs. CONCLUSIONS AND CLINICAL RELEVANCE CT imaging characteristics described in this study may provide a reference for dimensions and appearance of SLNs of healthy dogs and serve as a basis for comparison with results for diseased dogs.