Algorithmic estimation of adrenal volume based on body weight and CT landmarks in dogs.

Computed tomographic (CT) methods for quantifying adrenal size are helpful for identifying and directing management of adrenal disease in dogs. This retrospective, observational study aimed to use CT to determine anatomic landmarks associated with adrenal gland volume in dogs, and subsequently develop an algorithm to estimate adrenal volume for individual subjects. Abdominal CT images from 150 dogs without adrenal disease were assessed. The volume of the left and right adrenals, as well as dimensions from anatomic structures, were measured. Predictive models for adrenal volume were examined with cross validation. A further 29 dogs were used for external validation and model fit. Dogs in the test cohort weighed from 3.1 to 67.5 kg (mean 24.4 kg) with left (VLA ) and right (VRA ) adrenal volume ranging from 0.23 to 2.84 cm3 (mean 1.22 cm3 ) and 0.14 to 2.97 cm3 (mean 1.11 cm3 ), respectively. A predictive model for each adrenal based on weight (W) and L1 height (HL1 ) best explained the adrenal volume, with external validation confirming model fit. The final models, adjusted for bias, were: VLA  = 0.154 + (0.02 × W) + (0.07 × HL1 ) (adjR2  = 0.62); and VRA  = -0.116 + (0.02 × W) + (0.06 × HL1 ) (adjR2  = 0.64). In dogs undergoing CT, these algorithms can be used to estimate expected adrenal volume and allow comparison with the actual volume measured on CT, facilitating interpretation of CT findings, and clinical decision-making.

Association between computed tomographic thoracic injury scores and blood gas and acid-base balance in dogs with blunt thoracic trauma.

OBJECTIVE: To determine the association between thoracic injuries evaluated by computed tomography (CT) and arterial blood gas and acid-base status in dogs with blunt thoracic trauma caused by motor vehicle accidents. DESIGN: Prospective observational clinical study. SETTING: University teaching hospital. ANIMALS: Thirty-one client owned traumatized dogs and 15 healthy dogs. PROCEDURES: All trauma group dogs underwent a CT scan and simultaneous arterial blood gas analysis within 24 hours, but not before 4 hours, after the traumatic incident within a 45-month enrollment period. MEASUREMENTS AND MAIN RESULTS: Thorax injuries were classified as pulmonary, pleural space, or rib cage and each of these components was scored for severity using a CT composite pulmonary, pleural, and rib score. The trauma group arterial blood gas and acid-base status were evaluated for statistical difference from the control group. The pulmonary-arterial oxygen pressure was significantly lower in the trauma group compared to the control group that was supported by significant differences in the calculated variables of arterial blood oxygenation as well. There was also a significant correlation between the composite lung score and pleural score and the variables of arterial oxygen status. The pulmonary-arterial carbon dioxide pressure was not significantly different to any of the thoracic injury variables indicating normal alveolar ventilation. Acid-base imbalances were generally mild, insignificant, and variable. CONCLUSIONS AND CLINICAL RELEVANCE: Blunt thoracic trauma causes significant pulmonary and pleural injury and the blood oxygen economy is significantly affected by this. The functional measures of arterial blood oxygenation were well correlated with thoracic CT pathology. Alveolar ventilation was mostly spared but a clinically significant ventilation perfusion mismatch was present.

Triple phase dynamic computed tomographic perfusion characteristics of spirocercosis induced esophageal nodules in non-neoplastic versus neoplastic canine cases.

Neoplastic transformation of Spirocerca lupi induced esophageal nodules carries a poor prognosis. Clinical, clinicopathological, endoscopic, and radiographic characteristics may be indicative of neoplastic transformation but variable sensitivity and specificity of these parameters makes their use questionable. We hypothesized that CT would be a better diagnostic modality to discriminate between non-neoplastic and neoplastic nodules. In this prospective study of 38 dogs, the appearance and perfusion characteristics of confirmed spirocercosis-induced neoplastic and non-neoplastic esophageal nodules were described using survey CT and triple phase dynamic CT angiography (CTA). Pre- and post-contrast early arterial, late arterial, and venous CTA images were evaluated. Non-neoplastic nodules were smooth and nonmineralized with a higher proportion of hypoattenuating necropurulent cavities compared to neoplastic nodules that had a more irregular surface, with 93% having mineralized foci and rarely any hypoattenuating pockets. Non-neoplastic nodules were significantly more perfused than neoplastic nodules with the difference being up to 23 Hounsfield units. The difference was most marked in the early and late arterial phases (P = 0.0005 and 0.00005, respectively). Ratios of the normal esophagus adjacent to the neoplastic and non-neoplastic nodules did not differ significantly from each other. Perfusion findings demonstrated relative hypoperfusion of the esophageal sarcomas. Findings from the current study indicated that CT characteristics of relative postcontrast hypoperfusion, combined with nodule irregularity and mineralization warrant a high level of concern for neoplastic transformation in canine spirocercosis-induced esophageal nodules.

Computed tomographic and radiographic characteristics of aortic lesions in 42 dogs with spirocercosis.

Spirocerca lupi is a common cause of vomiting, regurgitation, and sudden death in dogs that live in tropical or subtropical regions. Sudden death due to aortic rupture may occur with no preceding clinical signs. The purpose of this prospective study was to compare radiographic and computed tomographic (CT) characteristics of aortic lesions in a cohort of 42 dogs with endoscopically confirmed spirocercosis. Dorsoventral and right lateral recumbent thoracic radiographic findings were compared with pre- and postcontrast thoracic CT findings. Aortic mineralization was detected using CT in 18/42 dogs (43%). Three dogs had faint diffuse aortic wall mineralization. Using CT as the reference standard, radiographs had a sensitivity and specificity of 6% and 96%, respectively, for detecting aortic mineralization. A total of 20 aortic aneurysms were detected using CT in 15/42 dogs (36%). Using CT as the reference standard, radiographs had a sensitivity and specificity of 86% and 56%, respectively, for detecting aortic aneurysms. Respiratory motion, aortic displacement by esophageal masses and Spirocerca nodules adjacent to the aorta mimicked aneurysm formation on radiographs. Aortic thrombi were seen in two dogs in postcontrast CT images. Findings from this study indicated that aortic mineralization and aneurysm formation are common in dogs with spirocercosis. Findings also supported the use of pre- and postcontrast CT as effective methods for detecting and characterizing these lesions.

Ultrasonographic appearance of canine parvoviral enteritis in puppies.

The ultrasonographic appearance of the gastrointestinal tract of puppies suffering from parvoviral enteritis was characterized. Forty puppies between 6 and 24 weeks of age with confirmed canine parvoviral enteritis were examined ultrasonographically within 24 h of admission. Sonographic findings included fluid-filled small intestines in 92.5% of subjects, and stomach and colon in 80% and 62.5% of subjects, respectively. Generalized atony was present in 30 subjects and weak peristaltic contractions indicative of functional ileus observed in the remaining 10 subjects. The duodenal and jejunal mucosal layer thicknesses were significantly reduced when compared with normal puppies with mean duodenal mucosal layer measuring 1.7 mm and jejunal mucosal layer 1.0 mm. Additionally, a mucosal layer with diffuse hyperechoic speckles was seen in the duodenum (15% of subjects) and the jejunum (50% of subjects). The luminal surface of the duodenal mucosa was irregular in 22.5% of subjects and the jejunal mucosa in 42.5% of subjects. In all of these subjects, changes were accompanied by generalized indistinct wall layering. Small intestinal corrugations were seen within the duodenum in 35% of subjects and within the jejunum in 7.5%. A mild amount of anechoic free peritoneal fluid was observed in 26 subjects and was considered within normal limits and a moderate amount of anechoic free peritoneal fluid was observed in six subjects. The jejunal lymph node size was within normal limits. None of the above changes are pathognomonic for canine parvoviral enteritis but finding them in combination is highly suggestive.

Normal canine pediatric gastrointestinal ultrasonography.

The normal sonographic appearance of the adult canine gastrointestinal tract has been described. Interpretation of abdominal ultrasonographic findings in puppies is difficult due to the lack of information on normal ultrasonographic findings. The gastrointestinal tract, jejunal lymph node size and the presence and appearance of abdominal fluid were investigated in 23 normal, 7-12-week-old Beagle puppies. The duodenal wall thickness was greater than in other parts of the gastrointestinal tract (mean 3.8 +/- standard deviation [SD] 5 mm, range 3.2-4.8 mm). The mean stomach wall thickness was 2.7 +/- SD 0.4 mm (range 2.2-3.7 mm), the mean jejunal wall thickness was 2.5 +/- SD 0.5 mm (range 1.2-3.4 mm), and the mean colonic wall thickness was 1.3 +/- SD 0.3 mm (range 0.7-2.0 mm). In addition, mean duodenal and jejunal mucosal layer thicknesses measured 2.7 +/- SD 0.5 mm (range 2.0-3.8 mm) and 1.5 +/- SD 0.4 mm (range 0.6-2.5 mm), respectively. Homogenous, hypoechoic jejunal lymph nodes were easily found and the mean thickness was 7.1 +/- SD 2.2 mm (range 1.5-12.5 mm). A mild amount of anechoic free peritoneal fluid was present in all puppies.