Ultrasonographic Appearance of Gallbladder Neoplasia in 14 Dogs and 1 Cat.

Ultrasonography is the most commonly used diagnostic imaging tool for gallbladder disease in veterinary medicine. Primary gallbladder neoplasia is an uncommon finding with variable prognosis for which no studies have been published describing their ultrasonographic appearance and diagnosis. This retrospective, multicenter, case series study examines the ultrasonographic appearance of gallbladder neoplasia with histologically or cytologically confirmed diagnoses. A total of 14 dogs and 1 cat were analyzed. All discrete masses were sessile in shape and varied in size, echogenicity, location, and gallbladder wall thickening. All studies with images showing Doppler interrogation exhibited vascularity. Cholecystoliths were an uncommon finding, being present in only one case in this study, unlike in humans. The final diagnosis of the gallbladder neoplasia was neuroendocrine carcinoma (8), leiomyoma (3), lymphoma (1), gastrointestinal stromal tumor (1), extrahepatic cholangiocellular carcinoma (1), and adenoma (1). Findings from this study indicate that primary gallbladder neoplasms have variable sonographic appearances and cytologic and histologic diagnoses.

Interpretation of cardiac chamber size on canine thoracic radiographs is limited and may result in the false identification of right-sided cardiomegaly in the presence of severe left-sided cardiomegaly.

Qualitative assessment of individual cardiac chamber enlargement on thoracic radiographs was assessed using echocardiography as the gold standard in dogs. Using this method, the presence of severe left-sided cardiomegaly was hypothesized to contribute to the false identification of right-sided cardiomegaly on radiographs. 175 dogs with three-view thoracic radiographs were retrospectively included in this diagnostic accuracy study if echocardiography was done within 24 h, and no rescue therapy was provided in the interim. All radiographic studies were reviewed by two groups of five board-certified veterinary radiologists with greater and less than 10 years of experience for grading of cardiac chamber enlargement as normal or mildly, moderately, or severely enlarged. The agreement, sensitivity, and specificity of the radiologists' interpretation of cardiac chamber size on thoracic radiographs to measured echocardiographic grades were evaluated. A total of 147 cases had complete echocardiographic data available for analysis. Intragroup agreement was moderate for the evaluation of left atrial enlargement and slight to fair for all other cardiac chambers. Between the mode of the radiologists' responses in the two groups and the echocardiographic grades, there was slight agreement for all cardiac chambers with higher severity grades reported using echocardiography. When moderate to severe left-sided cardiomegaly was identified on echocardiography, the sensitivity, specificity, and accuracy of radiographs were low, identifying dogs with radiographic evidence of right-sided cardiomegaly in the absence of corresponding right-sided cardiomegaly on echocardiography. Therefore, thoracic radiographs should be used with caution for the evaluation of cardiac chamber enlargement, particularly in the presence of severe left-sided cardiomegaly.

Ultrasound elastography of the liver, spleen, and kidneys in clinically normal cats.

A large amount of overlap exists in the B-mode ultrasound appearance of normal and abnormal liver, spleen, and kidney tissues in cats. Therefore, invasive tissue sampling procedures remain the standard method for diagnosing diseases in these organs. The purpose of our study was to assess the feasibility of ultrasound elastography as a technique for improving noninvasive characterization of the feline liver, spleen, and kidneys. Elastography was performed on 10 unsedated, clinically healthy cats. Numeric (strain) values (0 = softest to 255 = firmest) assigned to color pixels within regions of interest resulted in median scores (interquartile ranges) of body wall, 207.50 (189.75-224.00); liver, 119.00 (105.00-138.25); spleen, 127.50 (121-00-142.00); right renal cortex, 83.50 (64.00-130.00); right renal near field, 125.50 (110.75-139.75); left renal cortex, 77.50 (52.00-116.25); and left renal near field, 126.00 (114.00-145.25). Strain values were not different between organs. Body wall median was the only significantly different value (P < 0.05). Strain ratio values of body wall:organ were as follows: liver, 1.76 (1.38-2.00); spleen, 1.68 (1.47-1.83); right renal cortex, 2.31 (1.61-3.15); right renal near field, 1.62 (1.41-2.01); left renal cortex, 2.66 (1.45-4.13); and left renal near field, 1.51 (1.29-1.89). Subjectively, hepatic and splenic parenchymal tissues were homogeneous in compressibility and similar in elasticity to one another. Renal cortical tissue was softer compared to medullary tissue. Findings indicated that ultrasound elastography is a feasible technique for objectively and subjectively characterizing the feline liver, spleen, and kidneys. Further research is needed in cats with confirmed diseases of these organs, to compare the diagnostic sensitivity of ultrasound elastography vs. B-mode ultrasonography.

Radiographic analysis of the dorsal hoof wall thickness in clinically normal draft horses.

OBJECTIVE: To evaluate the radiographic thickness of the dorsal hoof wall in normal draft horse feet. ANIMALS: 33 adult draft horses with no history of laminitis, no clinically obvious lameness, and visibly unremarkable front feet were included. METHODS: This was a prospective, descriptive study of clinically normal draft horses' front feet. Lateromedial radiographs were acquired of the front feet. A ratio of the dorsal hoof wall thickness to the length of the distal phalanx (DHWP3 ratio) was calculated. RESULTS: The dorsal hoof wall thickness to length of the distal phalanx was calculated as 0.33 ± 0.03 (range of 0.28 to 0.39) in this population of draft horses. CLINICAL RELEVANCE: With very few exceptions, the heterogeneous population of draft horses evaluated in this study had a DHWP3 ratio greater than previously published values in lighter breeds (< 0.30).

Comparison of thoracic and abdominal cavity volumes during abdominal CO2 insufflation and abdominal wall lift.

OBJECTIVE: To compare thoracic and abdominal cavity volumes during abdominal CO2 insufflation and abdominal wall lift (AWL) conditions. STUDY DESIGN: In vitro cadaveric study. ANIMALS: Mature medium-to-large breed fresh canine cadavers (n = 6). METHODS: Each cadaver was imaged with computed tomography (CT) under baseline, abdominal CO2 insufflation, and AWL conditions. Measurements of thoracic and abdominal cavities were performed for each condition using image-analyzing software. Resulting volumes for each cadaver were converted to percent change from baseline to normalize the data. The t-tests were used to compare percent changes of both thoracic and abdominal volumes. RESULTS: Thoracic volume significantly decreased from baseline during CO2 insufflation (P < .01). No significant difference in thoracic volume occurred with AWL when compared with baseline. Abdominal volume increased by 80% with CO2 insufflation (95% CI: 56.4-107.0%) but only 25% with AWL (95% CI: 12.3-37.8%). CONCLUSIONS: Abdominal CO2 insufflation results in decreased thoracic volume when compared with baseline. AWL preserved thoracic volume similar to baseline. Abdominal volumes achieved with abdominal CO2 insufflation are significantly greater than those attained with AWL.

Pandemic swine-origin H1N1 influenza A virus isolates show heterogeneous virulence in macaques.

The first influenza pandemic of the new millennium was caused by a newly emerged swine-origin influenza virus (SOIV) (H1N1). This new virus is characterized by a previously unknown constellation of gene segments derived from North American and Eurasian swine lineages and the absence of common markers predictive of human adaptation. Overall, human infections appeared to be mild, but an alarming number of young individuals presented with symptoms atypical for seasonal influenza. The new SOIV also showed a sustained human-to-human transmissibility and higher reproduction ratio than common seasonal viruses, altogether indicating a higher pathogenic potential for this newly emerged virus. To study the virulence of the SOIV, we used a recently established cynomolgus macaque model and compared parameters of clinical disease, virology, host responses, and pathology/histopathology with a current seasonal H1N1 virus. We here show that infection of macaques with two genetically similar but clinically distinct SOIV isolates from the early stage of the pandemic (A/Mexico/4108/2009 and A/Mexico/InDRE4487/2009) resulted in upper and lower respiratory tract infections and clinical disease ranging from mild to severe pneumonia that was clearly advanced over the mild infection caused by A/Kawasaki/UTK-4/2009, a current seasonal strain. Unexpectedly, we observed heterogeneity among the two SOIV isolates in virus replication, host transcriptional and cytokine responses, and disease progression, demonstrating a higher pathogenic potential for A/Mexico/InDRE4487/2009. Differences in virulence may explain more severe disease, as was seen with certain individuals infected with the emerged pandemic influenza virus. Thus, the nonhuman primate model closely mimics influenza in humans.

Skeletal muscles of hibernating brown bears are unusually resistant to effects of denervation.

Hibernating bears retain most of their skeletal muscle strength despite drastically reduced weight-bearing activity. Regular neural activation of muscles is a potential mechanism by which muscle atrophy could be limited. However, both mechanical loading and neural activity are usually necessary to maintain muscle size. An alternative mechanism is that the signaling pathways related to the regulation of muscle size could be altered so that neither mechanical nor neural inputs are needed for retaining strength. More specifically, we hypothesized that muscles in hibernating bears are resistant to a severe reduction in neural activation. To test this hypothesis, we unilaterally transected the common peroneal nerve, which innervates ankle flexor muscles, in hibernating and summer-active brown bears (Ursus arctos). In hibernating bears, the long digital extensor (LDE) and cranial tibial (CT) musculotendon masses on the denervated side decreased after 11 weeks post-surgery by 18 ± 11 and 25 ± 10%, respectively, compared with those in the intact side. In contrast, decreases in musculotendon masses of summer-active bears after denervation were 61 ± 4 and 58 ± 5% in the LDE and CT, respectively, and significantly different from those of hibernating bears. The decrease due to denervation in summer-active bears was comparable to that occurring in other mammals. Whole-muscle cross-sectional areas (CSAs) measured from ultrasound images and myofiber CSAs measured from biopsies decreased similarly to musculotendon mass. Thus, hibernating bears alter skeletal muscle catabolic pathways regulated by neural activity, and exploration of these pathways may offer potential solutions for disuse atrophy of muscles.

An insertion mutation in ABCB4 is associated with gallbladder mucocele formation in dogs.

BACKGROUND: ABCB4 functions as a phosphatidylcholine translocater, flipping phosphatidylcholine across hepatocyte canalicular membranes into biliary canaliculi. In people, ABCB4 gene mutations are associated with several disease syndromes including intrahepatic cholestasis of pregnancy, progressive familial intrahepatic cholestasis (type 3), primary biliary cirrhosis, and cholelithiasis. Hepatobiliary disease, specifically gallbladder mucocele formation, has been recognized with increased frequency in dogs during the past decade. Because Shetland Sheepdogs are considered to be predisposed to gallbladder mucoceles, we initially investigated ABCB4 as a candidate gene for gallbladder mucocele formation in that breed, but included affected dogs of other breeds as well. RESULTS: An insertion (G) mutation in exon 12 of canine ABCB4 (ABCB4 1583_1584G) was found to be significantly associated with hepatobiliary disease in Shetland Sheepdogs specifically (P < 0.0001) as well as other breeds (P < 0.0006). ABCB4 1583_1584G results in a frame shift generating four stop codons that prematurely terminate ABCB4 protein synthesis within exon 12, abolishing over half of the protein including critical ATP and a putative substrate binding site. CONCLUSIONS: The finding of a significant association of ABCB4 1583_1584G with gallbladder mucoceles in dogs suggests that this phospholipid flippase may play a role in the pathophysiology of this disorder. Affected dogs may provide a useful model for identifying novel treatment strategies for ABCB4-associated hepatobiliary disease in people.

Kinetics of inhibition of purified bovine neutrophil matrix metalloproteinase 9 by low-molecular-weight inhibitors.

OBJECTIVE: To measure the effects of lowmolecular-weight inhibitors on the activity of bovine neutrophil matrix metalloproteinase 9 (MMP-9). SAMPLE POPULATION: Bovine MMP-9 purified from bovine neutrophilconditioned medium. PROCEDURES: Neutrophils were degranulated by stimulation with phorbol ester. Enzyme purification was performed by use of gelatin affinity and gel-filtration chromatography. Activated enzyme was incubated with inhibitors prior to addition of substrate (gelatin fluorescein conjugate or fluorogenic peptide). Rates of enzymatic cleavage were determined by monitoring fluorescence as the reactions progressed. Values of IC(50) (molar concentration of compound that inhibits specific activity by 50%) and K(I) (in vitro inhibition constant) were determined. RESULTS: Rates of enzymatic activity of monomeric and dimeric bovine MMP-9 measured by use of gelatin and peptide substrates were linear with respect to time and concentrations of enzyme and substrate. The MMP-9 was potently inhibited by hydroxamic acids (IC(50) for gelatin, 29.2 to 55.7 nM; IC(50) for peptide, 4.8 to 24.6 nM; K(I), 0.2 to 0.5 nM), whereas tetracyclines (IC(50) for gelatin, 30.1 to 112.7 MM; IC(50) for peptide, 48.0 to 123.8 MM; K(I), 25.2 to 61.4 microM) and chlorhexidine (IC(50) for gelatin, 139.1MM; IC(50) for peptide, 672.5MM to 1.7 mM; K(I), 495.0 to 663.0 MM) had limited inhibition. Gelatinase-specific inhibitor SB-3CT had intermediate potency (IC(50) for peptide, 185.0 to 290.0 nM; K(I), 66.5 to 86.0 nM). CONCLUSIONS AND CLINICAL RELEVANCE: Bovine MMP-9 was potently inhibited by hydroxamic acids and gelatinase inhibitor. These compounds may be useful as modulators of neutrophil-mediated protease activity in cattle.

Use of non-contrast-enhanced computed tomography to identify deep digital flexor tendinopathy in horses with lameness: 28 cases (2014-2016).

OBJECTIVE: To describe the use of non-contrast-enhanced CT to identify deep digital flexor (DDF) tendinopathy in horses with lameness attributed to pain in regions distal to the metatarsophalangeal or metacarpophalangeal joints. DESIGN: Retrospective case series. ANIMALS: 28 client-owned horses. PROCEDURES: Medical records were searched to identify horses that underwent non-contrast-enhanced CT with or without high-field MRI as part of an evaluation for lameness localized to areas distal to the metacarpophalangeal or metatarsophalangeal joint in ≥ 1 limb. Horses were included in the study if they had ≥ 1 DDF tendon lesion (DDF tendinopathy) identified. Signalment, lameness examination findings and response to perineural anesthesia, imaging modality, anesthetic agents and duration of anesthesia, and imaging findings were recorded. Data were summarized descriptively. RESULTS: Bilateral imaging was performed for all horses, irrespective of unilateral or bilateral lameness. Nine of 28 horses underwent both CT and MRI, and all DDF tendon lesions identified by one modality were identified by the other. Of 48 limbs with DDF tendinopathy, 46 (96%) had core lesions and 35 (73%) had dorsal border irregularities. Median anesthesia time for CT and CT followed by MRI was 15 and 110 minutes, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that non-contrast-enhanced CT was useful for identifying DDF tendinopathy in horses with lameness localized to the phalangeal regions, and this was supported by consistency of findings in a subset of horses that underwent MRI. Further research is needed to confirm these results.

Radiographic evaluation of patellar ligament length after tibial plateau leveling osteotomy in dogs.

OBJECTIVE: To radiographically compare patellar ligament length (PLL) in dogs undergoing tibial plateau leveling osteotomy (TPLO) for unilateral cranial cruciate ligament rupture at preoperative, postoperative, and follow-up evaluations. ANIMALS: 105 dogs that underwent TPLO for unilateral cranial cruciate ligament rupture at a referral veterinary hospital from October 1, 2008, through November 30, 2017. PROCEDURES: Medical records were reviewed to obtain information on dog signalment, surgical procedure, and radiographically measured PLL at preoperative, postoperative, and follow-up evaluations. RESULTS: Dogs undergoing TPLO had a shorter PLL at the postoperative and follow-up evaluations, compared with the PLL at the preoperative evaluation. Mean ± SD overall unadjusted PLL decreased significantly by 2.3 ± 3.4% between the preoperative and postoperative evaluation and by 2.8 ± 3.9% between the preoperative and follow-up evaluation. The PLL did not differ significantly between the postoperative and follow-up evaluation; mean PLL decreased by 0.4 ± 3.8% between the postoperative and follow-up evaluation. CONCLUSIONS AND CLINICAL RELEVANCE: The PLL was shorter after TPLO in dogs, which was similar to changes observed for humans after high tibial osteotomy procedures. Further evaluation of clinical assessments, joint mobility, ultrasonographic assessments, and kinematic results are needed to determine the relevance of the PLL and whether a decrease in ligament length results in decreased mobility and persistent lameness in dogs, as has been reported for humans.

Metacarpophalangeal collateral ligament reconstruction using small intestinal submucosa in an equine model.

Xenogeneic porcine small intestinal submucosa (SIS) is a natural, biodegradable matrix that has been successfully used as a scaffold for repair of tissue defects. The goal of this study was to compare a collateral ligament transection surgically reconstructed with an anchored SIS ligament to a sham-operated control procedure for the correction of joint laxity using an equine model. Ten metacarpophalangeal joints from 10 horses had complete transection of the lateral collateral ligament. In 6 horses, the collateral ligament was reconstructed with a multilaminate strip of SIS anchored with screws into bone tunnels proximal and distal to the joint. The sham controls had similar screws, but no SIS placed. Clinical compatibility and effectiveness were evaluated with lameness, incisional quality, and joint range of motion, circumference and laxity. Ligament structure and strength was quantified with serial high resolution ultrasound, histology, and mechanical testing at 8 weeks. Surgical repair with SIS eliminated joint laxity at surgery. SIS-treated joints had significantly less laxity than sham treatment at 8 weeks (p < 0.001). SIS-treated ligaments demonstrated a progressive increase in repair tissue density and fiber alignment that by week 8 were significantly greater than sham-treated ligament (p < 0.03). SIS-repaired ligament tended to have greater peak stress to failure than sham-treatment (p < 0.07). Cellularity within the ligament repair tissue and inflammation within the bone tunnel was significantly greater in the SIS-treated limbs (p < 0.017). Within the first 8 weeks of healing, SIS implanted to reinforce collateral ligament injury was biocompatible in the joint environment, restored initial loss of joint stability, and accelerated early repair tissue quality. SIS ligament reconstruction might provide benefit to early ligament healing and assist early joint stability associated with ligament injury.

Ultrasound biomicroscopy of the iridocorneal angle of the eye before and after phacoemulsification and intraocular lens implantation in dogs.

OBJECTIVE: To compare the iridocorneal angle (ICA) and angle opening distance (AOD) in dogs with cataractous and noncataractous lenses; evaluate cataractous eyes ultrasono-graphically for association of postoperative ocular hypertension (POH) with the ICA, AOD, and postoperative echogenic anterior chamber debris; and evaluate intraobserver reliability associated with ICA and AOD measurements. ANIMALS: 56 dogs with 102 cataracts, and 23 clinically normal dogs. PROCEDURES: Ultrasound biomicroscopy was performed on 102 eyes of 56 dogs before and after cataract surgery and on 46 nondilated and dilated eyes of 23 clinically normal dogs. Cataract stage, ICA, AOD, and association with POH were assessed. RESULTS: Cataract stage and ICA or AOD were not significantly associated; however, ICA and AOD typically decreased with increasing cataract maturity. Before and after pupillary dilation, AODs were significantly smaller in cataractous eyes than in noncataractous eyes. Before surgery, ICA and AOD in eyes without pupillary dilation were significantly associated with POH. At > 13 degrees , odds of developing POH increased by 11% for each degree increase in the ICA. Postoperative anterior chamber debris was not associated with POH. Coefficient of variation for repeated measurements was 10% for the ICA and 9.5% for the AOD, suggesting good intraobserver reliability. CONCLUSIONS AND CLINICAL RELEVANCE: In this study, dogs with larger ICA and AOD measurements before surgery were at greater risk of developing POH. This information may be useful for future studies to determine whether preventative treatment for POH administered prior to surgery may be beneficial.

Subchondral bone density and cartilage degeneration patterns in osteoarthritic metacarpal condyles of horses.

OBJECTIVE: To evaluate and correlate patterns of subchondral bone density and articular cartilage degeneration (derived by use of gross, histologic, and computed tomographic [CT] examinations) in equine third metacarpal condyles with and without osteoarthritis. SAMPLE POPULATION: 8 metacarpophalangeal (MCP) joints (n = 4 horses) without osteoarthritis and 6 osteoarthritis-affected MCP joints (4). PROCEDURES: Horses were euthanized. The third metacarpal condyles of the joints were examined grossly and via CT (3 slice images/condyle). For 6 condylar zones, mean bone density and pattern of density distribution were determined. Data for osteoarthritis-affected and control joints were compared. Histomorphometric point count analyses identified areas of bone density for comparison with CT density measurements. RESULTS: Osteoarthritis-affected condyles had heterogeneous subchondral bone with focal resorptive lesions and patterned sclerosis, whereas control condyles had symmetric bone density distribution. In osteoarthritis-affected condyles, bone density determined via gray scale image density analysis was greater (dorsal and medial pattern), compared with control condyles, and differed among zones because of resorption and sclerosis. With regard to bone density in osteoarthritis-affected condyles, histologic findings correlated with CT images, and bone lesions were significantly correlated with cartilage lesions. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, heterogeneous distribution and greater subchondral bone density were characteristic of osteoarthritis-affected condyles, compared with control condyles. Subchondral bone lesions correlated with overlying cartilage lesions in osteoarthritis-affected MCP joints. Identification of CT image characteristics appears to predict the presence of a cartilage lesion in MCP joints of horses with osteoarthritis.

Biochemical and enzymatic characterization of purified covalent complexes of matrix metalloproteinase-9 and haptoglobin released by bovine granulocytes in vitro.

OBJECTIVE: To characterize and purify covalent complexes of matrix metalloproteinase-9 (MMP-9) and haptoglobin released by bovine granulocytes in vitro. SAMPLE POPULATION: Blood samples obtained from healthy cows and cows with acute and chronic inflammation to obtain WBCs and sera. PROCEDURES: WBCs were isolated by differential centrifugation, hypotonic lysis of RBCs, and degranulated by stimulation with phorbol ester (20 ng/mL). Cell-conditioned medium was subjected to affinity and gel chromatography and purified proteins subjected to SDS- PAGE gelatin zymography, western blot analysis, Coomassie blue staining, and peptide mass spectrometry for protein identification. Sera of cows hospitalized for acute and chronic septic conditions and of clinically normal cows were analyzed with similar methods. RESULTS: Matrix metalloproteinase-9 was released from neutrophils in vitro and migrated to a molecular mass of approximately 220 kd (prodimer), approximately 105 kd (promonomer), and > 220 kd (high-molecular mass complexes). These high-molecular mass complexes were composed of alpha- and beta-haptoglobin and MMP-9 (ratio13:13:1). Complexes of MMP-9 and haptoglobin had biochemical properties of both its protein constituents (i.e., enzymatic activity toward gelatin and hemoglobin binding). Complexes of MMP-9 and haptoglobin were also detected in sera of cows with acute inflammation, but not in clinically normal cows or cows with chronic disease. CONCLUSIONS AND CLINICAL RELEVANCE: A fraction of neutrophil MMP-9 is released in complex with haptoglobin. The complex is present in granules and retains biological activity of its components. Detection of the complex in serum may provide an indicator of acute inflammation.

Nanoparticles as image enhancing agents for ultrasonography.

Nanoparticles have drawn great attention as targeted imaging and/or therapeutic agents. The small size of the nanoparticles allows them to target cells that are beyond capillary vasculature, such as cancer cells. We investigated the effect of solid nanoparticles for enhancing ultrasonic grey scale images in tissue phantoms and mouse livers in vivo. Silica nanospheres (100 nm) were dispersed in agarose at 1-2.5% mass concentration and imaged by a high-resolution ultrasound imaging system (transducer centre frequency: 30 MHz). Polystyrene particles of different sizes (500-3000 nm) and concentrations (0.13-0.75% mass) were similarly dispersed in agarose and imaged. Mice were injected intravenously with nanoparticle suspensions in saline. B-mode images of the livers were acquired at different time points after particle injection. An automated computer program was used to quantify the grey scale changes. Ultrasonic reflections were observed from nanoparticle suspensions in agarose gels. The image brightness, i.e., mean grey scale level, increased with particle size and concentration. The mean grey scale of mouse livers also increased following particle administration. These results indicated that it is feasible to use solid nanoparticles as contrast enhancing agents for ultrasonic imaging.

Comparison of glomerular filtration rate between greyhounds and non-Greyhound dogs.

Greyhounds have significantly higher serum creatinine (SCr) concentration than do non-Greyhound dogs that may be attributable to differences in glomerular filtration rate (GFR). By means of plasma clearance of technetium Tc 99m diethylenetriaminepentaacetic acid, GFR was measured in 10 Greyhounds and 10 non-Greyhound dogs with normal findings of physical examination, CBC, serum biochemical analysis, and urinalysis. Dogs were fed the same diet for a minimum of 6 weeks before GFR data collection. Greyhounds had significantly higher mean +/- SD GFR (3.0 +/- 0.1 vs 2.5 +/- 0.2 ml/min/ kg; P = .01) and SCr concentration (1.8 +/- 0.1 vs 1.5 +/- 0.1 mg/dL; P = .03) than did non-Greyhound dogs, but the serum urea nitrogen (SUN) concentration was not significantly different (18 +/- 1 vs 18 +/- 2 mg/dL; P = .8). Therefore, the higher SCr concentration in Greyhounds is not attributable to decreased GFR, and may be associated with the high muscle mass in the breed. Healthy Greyhounds have higher GFR than do non-Greyhound dogs.

Use of helical computed tomography for measurement of thyroid glands in clinically normal cats.

OBJECTIVE: To determine the dimensions and volume of thyroid tissue in clinically normal cats by use of computed tomography. ANIMALS: 8 cats. PROCEDURE: Helical computed tomography images (2-mm collimation) were acquired from the cranial aspect of the second cervical vertebra through the caudal aspect of the fourth cervical vertebra. Data were acquired before contrast medium administration (n = 7 cats) and immediately after contrast medium enhancement (1 cat). Length, width, and height measurements of each thyroid lobe were made by use of transverse, dorsal, and sagittal plane images. Thyroid lobe volume was estimated by use of 3 methods. RESULTS: All thyroid lobes were histologically normal. Mean dimensions for a thyroid lobe were 16.5 x 2.00 x 4.31 mm (length x width x height) using only data from transverse images. Mean thyroid lobar volume was 113.75 mm(3) using the sum of areas method. Mean total volume of thyroid tissue was 215.25 mm(3) using the sum of areas method. CONCLUSIONS AND CLINICAL RELEVANCE: Results may be useful for computed tomography evaluation of abnormal thyroid glands in cats, which warrants investigation.