Fluoroscopically measured bronchial collapse in healthy dogs during cough exceeds 25%, and a cutoff of 60% bronchial collapse can be used to distinguish healthy from chronically coughing dogs.

Bronchomalacia, the weakening of bronchial cartilage, is a common cause of cough in dogs. The gold standard for diagnosis of bronchomalacia is bronchoscopy; however, fluoroscopy is often used as a preliminary diagnostic test due to its noninvasiveness. The normal amount of bronchial collapse in healthy dogs using fluoroscopy has not been previously established, with some authors citing <25%. The aims of this prospective and retrospective analytical observational study were to determine the normal amount of airway collapse in healthy animals, the amount of airway collapse in dogs with chronic cough and presumed bronchomalacia, and cut-off values of airway collapse during expiration and cough to distinguish between the two groups. Thoracic fluoroscopy was performed in right and left lateral recumbency during inspiration, expiration, and cough to evaluate the percentage collapse of the trachea and lobar bronchi in 45 healthy and 76 chronically coughing dogs. The bronchi of chronically coughing dogs exhibited a significantly greater amount of collapse during both expiration and cough compared with healthy dogs. Chronically coughing dogs exhibited up to 31.7 ± 26.6% collapse in expiration and 87.5 ± 23.7% collapse during cough, whereas healthy dogs exhibited 14.9 ± 6.1% collapse in expiration and 35.0 ± 13.7% collapse during cough. Based on ROC curves, the authors suggest using cut-off values of 30% during expiration and 60% during cough to distinguish between healthy dogs and those with presumed bronchomalacia. Findings suggest that though healthy dogs can exhibit a greater degree of airway collapse than previously thought, fluoroscopy can be used to distinguish between healthy and presumed bronchomalacic dogs.

Changes in glucose tolerance and insulin secretion in a cohort of cats with chronic obesity.

Obesity, which is the most common spontaneous nutritional disorder in cats, is a known risk factor for the development of diabetes mellitus and has been linked to insulin resistance, hyperinsulinemia, and altered adipose-derived hormone secretion in cats. The objective of this study was to monitor and report changes in the results of serial intravenous glucose tolerance testing (IVGTT) and other metabolic parameters in 4 obese cats over a 4-year period. Serial IVGTT, insulin sensitivity indices, adipokine concentrations, and lipid profiles were evaluated. All cats had IVGTT changes consistent with impaired glucose tolerance and altered insulin secretory patterns during the 4-year study period. There was no significant increase in the fasting blood glucose or insulin concentrations and no changes in the insulin sensitivity indices evaluated. The mean adiponectin concentration decreased significantly over time, but there was no significant increase in the leptin concentration and no changes were observed in lipid profiles. Although IVGTT can be used to document early and/or mild impairment of glucose tolerance and changes in insulin secretory pattern, this test cannot be easily or readily carried out on client-owned cats in most clinical settings. More work needs to be done to establish reliable, convenient methods for earlier identification of cats at risk of developing clinical diabetes mellitus.

L'obésité, qui est le désordre nutritionnel spontané le plus fréquent chez les chats, est un facteur de risque connu pour le développement du diabète mellitus et a été associé à une résistance à l'insuline, à de l'hyperinsulinémie et à une sécrétion altérée d'hormone dérivée du tissu adipeux chez les chats. L'objectif de cette étude était de surveiller et rapporter les changements dans les résultats de tests de tolérance au glucose intraveineux en série (IVGTT) et autres paramètres métaboliques chez quatre chats obèses sur une période de 4 ans. Des IVGTT en série, les indices de sensibilité à l'insuline, les concentrations d'adipokines et les profils lipidiques ont été évalués. Tous les chats avaient des changements d'IVGTT compatibles avec une tolérance réduite au glucose et des patrons de sécrétion d'insuline altérés durant la période d'étude de 4 ans. Il n'y avait pas d'augmentation significative des concentrations de glucose sanguin ou d'insuline à jeun et aucun changement dans les indices de sensibilité à l'insuline évalués. La concentration moyenne d'adiponectine a diminué de manière significative en fonction du temps, mais il n'y avait pas d'augmentation significative de la concentration de leptine et aucun changement n'a été observé dans les profils lipidiques. Bien que l'IVGTT peut être utilisé pour documenter une diminution naissante et/ou légère de la tolérance au glucose et des changements dans le patron de sécrétion d'insuline, ce test ne peut pas être réalisé facilement ou rapidement sur des chats de clients dans la plupart des milieux de pratique. Plus de travail doit être fait pour établir des méthodes fiables et pratiques pour une identification plus précoce des chats à risque de développer un diabète mellitus.(Traduit par Docteur Serge Messier).

Comparison of intraosseous and intravenous iodinated contrast administration for CT imaging in Hispaniolan Amazon parrots (Amazona ventralis).

Establishing and maintaining intravenous access for contrast medium during CT imaging can be difficult in birds due to their small size and thin walled vessels. Intraosseous (IO) catheters are an alternative to intravenous catheters and are often used for fluid or medication administration in birds. To determine the feasibility of IO iodinated contrast enhancement for CT in birds, 10 adult Hispaniolan Amazon parrots (Amazona ventralis) weighing 260-325 g, were enrolled in a prospective randomized blinded crossover group study to evaluate the differences in contrast route administration. The parrots underwent pre- and postcontrast CT scans using both routes of contrast administration with a wash-out period of at least 1 week between the two methods. Scans were evaluated subjectively for diagnostic quality and objectively with Hounsfield units measured over three organs: the brain, right kidney, and liver. All scans were diagnostic, and there was no statistically significant measurable difference in contrast enhancement between the two methods in any of the three organs. Subjectively, IO catheters were technically more difficult to place, but once in place, they were easier to manipulate for the imaging procedure and provided no complications upon removal. Minimal adverse side effects were noted from the IO catheters. In this small study, IO iodinated contrast administration was comparable in enhancement characteristics to intravenous administration for CT imaging in Hispaniolan Amazon parrots.

Accuracy of a drilling with a custom 3D printed guide or free-hand technique in canine experimental sacroiliac luxations.

OBJECTIVE: To improve the accuracy of drilling during the repair of sacroiliac luxations (SILs) with a 3D-printed patient-specific drill guide (3D-GDT) compared to free-hand drilling technique (FHDT). STUDY DESIGN: Blinded, randomized, prospective ex vivo study. SAMPLE POPULATION: Sixteen canine cadavers (20-25 kg). METHODS: Dorsal, bilateral SILs were created. Pelvic CT was performed pre- and post-drilling. The FHDT was drilled followed by 3D-GDT. CT and 3D measurements of craniocaudal and dorsoventral angles were compared between FHDT and 3D-GDT, as well as deviations of entry and exit points relative to optimal trajectory. RESULTS: Mean craniocaudal and dorsoventral angles for both CT- and 3D-measured 3D-GDT (CT 4.2 ± 3.9° and 3.9 ± 3.2°, respectively; 3D 5.1 ± 5.1° and 2.8 ± 2.3°, respectively p = .0006) were lower compared to FHDT (CT 11.8 ± 4.0°, p < .0001 and 8.9 ± 6.1°, p = .01; 3D 12.4 ± 5.9°, p = .0006 and 5.3 ± 5.24°, p = .05). Entry dorsoventral and end craniocaudal, dorsoventral, and 3D linear deviations were reduced with 3D-GDT. Sacral corridor disruption was present in 20% (3/15) for FHDT compared with 0% for 3D-GDT. CT and 3D analyses were in strong agreement (r = 0.77). CONCLUSION: Deviations of drill trajectories were minimized relative to optimal trajectories with 3D-GDT compared to FHDT in the dorsoventral and craniocaudal planes. CLINICAL SIGNIFICANCE: The use of 3D-GDT improves accuracy of sacral drilling compared with FHDT in canine cadavers. These results justify further evaluation in a clinical, prospective study.

Quantification of serum fibroblast growth factor-19 concentration in healthy dogs before and after feeding.

OBJECTIVE: To measure serum fibroblast growth factor-19 (FGF-19) concentration and gallbladder volume in healthy dogs before and after feeding to determine whether serum FGF-19 concentration increases following gallbladder contraction and to assess FGF-19 stability in blood samples kept under different storage conditions after collection in tubes containing no anticoagulant or in serum separator tubes. ANIMALS: 10 healthy dogs of various ages and breeds (30 blood samples and 30 gallbladder volume measurements). PROCEDURES: Serum FGF-19 concentration was measured with a commercially available ELISA. Gallbladder volume was determined ultrasonographically. Blood samples and gallbladder measurements were obtained from the dogs after food had been withheld for 12 hours (baseline) and at 1 and 3 hours after feeding. The stability of serum FGF-19 was assessed in samples collected in tubes containing no anticoagulant or in serum separator tubes and stored at -80°C for variable intervals or 4°C for 1 or 5 days. RESULTS: Serum FGF-19 concentration was significantly increased from baseline at 1 and 3 hours after feeding. There was a significant decrease in gallbladder volume 1 hour after feeding, compared with baseline findings. Regardless of collection tube used, concentrations of FGF-19 in serum obtained from blood samples that were collected and immediately stored at -80°C differed significantly from concentrations in serum obtained from blood samples that had been collected and stored at 4°C for 5 days. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that postprandial gallbladder contraction results in increases of serum FGF-19 concentration in healthy dogs. Assessment of circulating FGF-19 concentration could be used to detect disruptions in the enterohepatic-biliary axis in dogs.

CONTRAST-ENHANCED COMPUTED TOMOGRAPHIC FINDINGS OF APPARENTLY CLINICALLY NORMAL CHEETAH (ACINONYX JUBATUS) LIVERS.

Hepatic veno-occlusive disease (VOD) is a significant cause of morbidity and mortality in captive cheetahs (Acinonyx jubatus), and the appearance of this disease in humans by computed tomography (CT) has been well described. Contrast-enhanced CT abdominal scans of cheetahs without evidence of hepatic disease (n = 5) were reviewed retrospectively to describe the normal appearance of cheetah livers as an aid to antemortem VOD diagnosis. Despite having no clinical signs, clinical pathology abnormalities, or hepatic biopsy histopathology supportive of VOD, all five cheetahs had at least one VOD consistent finding on CT. The results of this study suggest that given the progressive and potentially subclinical nature of VOD, CT could serve as a noninvasive screening tool and be used to monitor disease progression.

Influence of repeat abdominal radiographs on the resolution of mechanical obstruction and gastrointestinal foreign material in dogs and cats.

Mechanical obstruction is a common cause of acute vomiting among small animals and radiography is the first line diagnostic tool. Due to many circumstances, surgery may not be an immediate treatment option. The purpose of this retrospective, cross-sectional design study is to determine the incidence of radiographic resolution of mechanical obstruction or gastrointestinal foreign material with medical management. Inclusion criteria included: clinical signs of vomiting, radiographic diagnosis of mechanical obstruction, suspect mechanical obstruction, foreign material suspected or definitively identified on the first set of radiographs and a second set of repeat radiographs within 36 h. Radiographic resolution was dependent on the location of dilation; 18/48 (37.5%) resolved were gastric, 6/35 (17.1%) were small intestinal, and 4/35 (11.4%) had concurrent gastric and small intestinal obstruction. Gastric dilation was more likely to resolve than SI dilation or both gastric and small intestinal dilation (P = .0119). Forty-nine animals without resolution went to surgery, with two developing pneumoperitoneum, and seven requiring intestinal resection, three of which had linear foreign bodies and three had intestinal masses/strictures. In conclusion, only 17.1% of animals with small intestinal dilation and a radiographic diagnosis of mechanical ileus resolved on repeat radiographs, and only 11.4% of animals with both small intestinal and gastric dilation resolved. Gastric dilation alone was more likely to resolve than small intestinal dilation or a combination of both. This may help to guide practitioners in recommendations for medical management of mechanical ileus in the future.

Dogs with biliary rupture based on ultrasound findings may have normal total serum bilirubin values.

The absence of hyperbilirubinemia can lead to decreased suspicion of biliary rupture in dogs. This delay of suspicion and treatment can result in increased mortality rates. The objective of this retrospective, observational study was to describe ultrasound and serum bilirubin findings in a group of dogs with an ultrasonographic diagnosis of suspected biliary rupture. The records of a single institution were searched over the period of 2007-2019 for cases having ultrasound reports describing suspicion of biliary rupture. Clinical findings for each of the cases were recorded. A total of 35 dogs met inclusion criteria and, of these, 30 dogs had confirmed ruptured biliary tracts. It was found that 40% (12/30) of dogs with confirmed ruptured biliary tracts had a serum bilirubin values within the normal reference range. No statistical difference was found in serum bilirubin values between the ruptured and nonruptured biliary tracts. Leukocytosis and neutrophilia were found to be statistically significant between ruptured and nonruptured biliary tracts. Mucinous material, similar to "white bile" found in human literature, was found within the peritoneal effusion of six dogs with biliary rupture, three of which also lacked bile pigment. Findings from this study indicated that normobilirubinemia may be present in some dogs with biliary rupture, and therefore should not be used as a reason for excluding this differential diagnosis.

Performing both lateral abdominal radiographs may not improve the visualization of gas in the gastric outflow tract of cats.

Reports in the veterinary literature support three-view abdominal radiographs as a standard of practice for evaluating dogs with suspected gastrointestinal (GI) diseases. The usefulness of three-view abdominal studies has not been evaluated in cats. Images from a prospective crossover group study with 20 healthy cats, and those from a retrospective cohort study of 110 cats, were reviewed and the location and degree of gas was assessed in the gastric outflow tract. Comparisons of the frequency of luminal gas were made between the views and between cats with GI disease versus cats without and between cats having sedation versus those without. Chi-Square analysis was performed with P < .05 being considered significant. No significant difference was found in the location and degree of luminal gas in left versus right lateral views in all cats regardless of the order in which the views were obtained or in cats with GI disease versus cats without. Cats with gastric dilation had a higher overall frequency of gas; those with dilation with homogeneous material were higher than those with dilation with heterogeneous material. A higher frequency of gas was found in sedated cats than nonsedated, but further study is needed to determine the underlying cause. Based on these findings, a three-view abdominal study for cats as a standard of practice may not be necessary, but obtaining the additional lateral view when gastric dilation is present might allow better visualization of the pyloric antrum and duodenum.

Wing Abnormality in a Wild-Hatched Whooping Crane (Grus americana) Chick from the Nonmigratory Population in Louisiana, USA.

We describe a wing abnormality in a wild-hatched Whooping Crane (Grus americana) chick from the reintroduced Louisiana, US nonmigratory population. Despite its seemingly compromised flight ability, the chick fledged, reached independence, and lived until 13 mo of age. Necropsy revealed an axial malunion near the left carpus likely resulting from trauma.

THE EFFECTS OF FOOD INTAKE AND ITS FAT COMPOSITION ON INTESTINAL ECHOGENICITY IN HEALTHY DOGS.

Dogs presenting for ultrasonography due to suspected gastrointestinal disease might have residual ingesta and this could have an affect on the appearance of intestinal mucosa unrelated to pathology. The purpose of this prospective descriptive study was to determine effects of a recent meal consisting of the recommended daily fat content (meal 1) and a higher fat one (meal 2) on mucosal echogenicity in healthy dogs. Sixty client-owned and clinically healthy dogs were recruited. Two meals, one with 15% fat dry matter basis (meal 1) and a second with 1.5 ml/kg body weight corn oil added to result in a range of 41-63% fat dry matter basis (meal 2), were fed 1 week apart after a 12 h fast. Mucosal echogenicity scores were assigned at fasting, immediate postprandial and at 60 min after each meal. Duodenal scores were significantly greater for meal 1 at 60 min (P < 0.001) as opposed to fasting and immediate postprandial. With meal 2, the duodenal score was significantly different (P < 0.001) at the immediate and 60-min data point compared to meal 1. Jejunal scores were significantly greater for meal 1 at the 60-min data point (P < 0.001) as opposed to fasting and immediate postprandial. With meal 2, the jejunal score was significantly different (P < 0.001) only at the 60-min data point compared to meal 1. Intestinal mucosal echogenicity can be increased in healthy dogs after food intake, regardless of fat content. This effect should be taken into consideration when increased mucosal echogenicity is identified in clinical patients.

EX VIVO CORRELATION OF ULTRASONOGRAPHIC SMALL INTESTINAL WALL LAYERING WITH HISTOLOGY IN DOGS.

Canine ultrasonographic intestinal layers have been reported to correlate with histological layering. However, discrepancies have been reported in people, and additional layers visualized. The aim of this method comparison study was to describe ex vivo canine small intestinal layering and correlate it with histology. Small intestinal samples of 12 adult dogs euthanized for reasons unrelated to gastrointestinal disease were resected immediately following euthanasia, pinned on a Petri dish, and transverse ultrasonographic images acquired in a water bath, using a high-frequency linear transducer. Transverse histological sections were obtained at the same level. Measurements of the intestinal layers were performed on the ultrasonographic and histological images. No significant statistical differences were noted between the ultrasonographic and histological measurements and strong to very strong (r > 0.7) positive correlation was observed for all layers, except for the serosa, which had a low moderate positive correlation (r = 0.479). In addition to the five established layers, a dual mucosal echogenicity was consistently observed, with seven samples presenting an additional inner mucosal severe hyperechogenicity. Histologically, this dual echogenicity was attributed to the intestinal villi (mildly echogenic) and lamina propria (hypoechoic). The additional inner mucosal severe hyperechogenicity observed in seven samples was attributed to mild-to-moderate lacteal dilation histologically. In 4/12 ileal samples, an additional hyperechoic mucosal line was also observed parallel to the submucosa, corresponding histologically to prominent Peyer's patches. Finally, a hyperechoic line was observed within the muscularis of all samples, corresponding histologically to the interface between the muscularis longitudinal and circular layers.

COMPUTED TOMOGRAPHIC MEASUREMENT OF THE MAIN PULMONARY ARTERY TO AORTIC DIAMETER RATIO IN HEALTHY DOGS: A COMPARISON TO ECHOCARDIOGRAPHICALLY DERIVED RATIOS.

Indicators of pulmonary hypertension in dogs examined with thoracic computed tomography (CT) are not well established in the veterinary literature. In humans, the main pulmonary artery to aortic diameter ratio (MPA:Ao) measured via CT, has been shown to be more sensitive than echocardiographic variables for predicting presence and severity of pulmonary hypertension, in some cases. In veterinary literature, the MPA:Ao has been determined echocardiographically to have an upper limit of about 1:1. Measurement of this ratio has not been described in dogs using CT. The objectives of this cross-sectional, prospective study were to compare echocardiographic measurement of MPA:Ao with that obtained via CT, determine if measurement of MPA:Ao via CT is repeatable and reproducible, and determine the effect of respiration and contrast administration on the measurement of MPA:Ao via CT. Ten healthy dogs without pulmonary hypertension were anesthetized to undergo thoracic CT using three protocols and echocardiography. The MPA:Ao was measured three times by three observers for each of the three CT protocols and compared to echocardiographic measurements. The mean MPA:Ao measured among all observers and CT protocols was 1.108 ± 0.152 (SD). The effect of CT scan protocol on MPA:Ao significantly differed among the three methods (P = 0.0014), where expiratory scans had lower MPA:Ao than inspiratory scans. The ratio measured on inspiratory CT scans consistently overestimated MPA:Ao when compared to echocardiography (bias = 0.226). Findings did not support the echocardiographically derived upper limit of MPA:Ao as an upper limit for determination of main pulmonary arterial enlargement on CT.

VARIABILITY IN THE ULTRASONOGRAPHIC APPEARANCE OF THE PANCREAS IN HEALTHY DOGS COMPARED TO DOGS WITH HYPERADRENOCORTICISM.

Anecdotally, an unusually hyperechoic pancreas can be found in seemingly healthy dogs on ultrasound examination and the prevalence and clinical significance of this finding is unknown. The objective of this study was to describe the prevalence of a hyperechoic and/or heterogenous pancreas in healthy dogs and correlate these findings to weight, age, and body condition score (BCS). An additional objective was to describe the prevalence of a hyperechoic and/or heterogenous pancreas in dogs with hyperadrenocorticism and compare this to the healthy dogs. Pancreata of 74 healthy dogs were evaluated prospectively and pancreatic echogenicity and echotexture were graded. Each dog's age, BCS, and weight were recorded. Dogs were screened for health by physical examination, serum chemistry panel, urine specific gravity, and a canine pancreatic lipase immunoreactivity assay. Pancreatic images for 92 dogs having hyperadrenocorticism were also reviewed and pancreatic echogenicity and echotexture were recorded. The prevalence of pancreatic hyperechogenicity in normal dogs was 7% (5 of 74) and heterogeneity was 40% (30 of 74). No correlation existed between pancreatic echogenicity and weight, age, or BCS (P > 0.1 for all sets). A statistically significant increase in the proportion of dogs having a hyperechoic pancreas was found in the hyperadrenocorticism sample of dogs (40%, 37 of 92, P < 0.0001). The underlying cause of pancreatic variability in the few healthy dogs and in dogs with hyperadrenocorticism is unknown and the varying appearance of the pancreas in these samples confounds interpretation of diseases such as chronic pancreatitis.

Evaluation of a ferret-specific formula for determining body surface area to improve chemotherapeutic dosing.

OBJECTIVE: To use CT-derived measurements to create a ferret-specific formula for body surface area (BSA) to improve chemotherapeutic dosing. ANIMALS: 25 adult ferrets (19 live and 6 cadavers). PROCEDURES: Live subjects were weighed, and body measurements were obtained by each of 3 observers while ferrets were awake and anesthetized. Computed tomography was performed, and a 3-D surface model was constructed with open-source imaging software, from which BSA was estimated. The CT-derived values were compared with BSA calculated on the basis of the traditional tape method for 6 cadavers. To further validate CT analysis software, 11 geometric shapes were scanned and their CT-derived values compared with those calculated directly via geometric formulas. Agreement between methods of surface area estimation was assessed with linear regression. Ferret-specific formulas for BSA were determined with nonlinear regression models. RESULTS: Repeatability among the 3 observers was good for all measurements, but some measurements differed significantly between awake and anesthetized ferrets. Excellent agreement was found between measured versus CT-derived surface area of shapes, traditional tape- versus CT-derived BSA of ferret cadavers, and CT-derived BSA of cadavers with and without monitoring equipment. All surface area formulas performed relatively similarly. CONCLUSIONS AND CLINICAL RELEVANCE: CT-derived BSA measurements of ferrets obtained via open-source imaging software were reliable. On the basis of study results, the recommended formula for BSA in ferrets would be 9.94 × (body weight)(2/3); however, this represented a relatively minor difference from the feline-derived formula currently used by most practitioners and would result in little practical change in drug doses.

Detection of comorbidities and synchronous primary tumours via thoracic radiography and abdominal ultrasonography and their influence on treatment outcome in dogs with soft tissue sarcomas, primary brain tumours and intranasal tumours.

Canine soft tissue sarcomas (STS), primary brain tumours and intranasal tumours are commonly treated with radiotherapy (RT). Given the low metastatic potential of these tumours, recommendations regarding imaging tests as staging are variable among institutions. The purpose of our study was to describe thoracic radiographic and abdominal ultrasonographic findings in dogs with these neoplasms and to investigate association of abnormal findings with alterations in recommended treatment. Medical records from 101 dogs, each having thoracic radiographs and abdominal ultrasound performed as part of their staging, were reviewed. In 98 of 101 (97%), imaging abnormalities were detected, 27% of which were further investigated with fine needle aspiration cytology or biopsy. Nine percent of the detected abnormalities were considered serious comorbidities that altered treatment recommendations, including 3 (3%) which were confirmed as synchronous primary neoplasms. These findings may influence recommendations regarding the decision to perform thoracic radiographs and abdominal ultrasound prior to initiation of RT.

Computed tomography features of bronchial and non-bronchial collateral arterial circulation development in a dog diagnosed with multiple chronic pulmonary thrombi.

A 5 year-old female Lhasa Apso was diagnosed with a large right pulmonary artery thrombus, multiple smaller pulmonary thrombi, and pulmonary hypertension. In addition, thoracic computed tomography angiography revealed numerous periesophageal arterial vessels, tortuous and dilated bronchial arteries, and an enlarged tortuous left phrenic artery, consistent with systemic bronchial and non-bronchial collateral arterial circulation development. These features of chronic pulmonary arterial thrombi have not been described in dogs but are recognized in people. One year after the diagnosis, the dog was still alive and there were no clinical signs reported.

Estimation of glomerular filtration rate in healthy cats using single-slice dynamic CT and Patlak plot analysis.

Commonly used clinical indicators of renal disease are either insensitive to early dysfunction or have delayed results. Decreased glomerular filtration rate (GFR) indicates renal dysfunction before there is a loss of 50% of functional nephrons. Most tests evaluate global rather than individual kidney function. Dynamic computed tomography (CT) and Patlak plot analysis allows for individual GFR to be tested. Our objectives were to establish a procedure and provide reference values for determination of global GFR in 10 healthy cats using dynamic CT (CTGFR). This method of GFR determination was compared against serum iohexol clearance (SIC). A single CT slice centered on both kidneys and the aorta was acquired every fifth second during and after a bolus injection of iohexol (240 mgI/ml; 300 mgI/kg) for 115 s. Using data from this dynamic acquisition, Patlak plots were obtained, GFR was calculated, and results were compared to global GFR determined by iohexol clearance. The average global CTGFR estimate was 1.84 ml/min x kg (SD = 0.43; range = [1.22, 2.45]). The average global GFR measured using SIC was 2.45 ml/min x kg (SD = 0.58; range = [1.72, 3.69]). GFR measurements estimated by both dynamic CT and SIC were positively associated (estimated Spearman rank correlation coefficient = 0.72; P = 0.0234). The CTGFR method consistently underestimated GFR with a bias of -0.62 (SE = 0.1307) when compared to SIC (P = 0.0011). In healthy cats, CTGFR was capable of determining individual kidney function and appears clinically promising.