Resolution of chronic regurgitation in an 8 month old Babydoll sheep by thoracoscopic treatment of a vascular ring anomaly.

OBJECTIVE: The objective was to describe the successful thoracoscopic treatment of esophageal entrapment resulting from a vascular ring anomaly (VRA) comprising a persistent right aortic arch (PRAA) and left ligamentum arteriosum (LA) in a Babydoll sheep wether. STUDY DESIGN: Case report. ANIMAL: Eight month old Babydoll sheep wether, 13 kg. METHODS: The patient presented with a weight half that of its sibling, persistent regurgitation following eating, and delayed growth noted from the age of approximately 2 months, coinciding with the introduction of solid feed into the diet. Plain thoracic radiographs were within normal limits but computed tomography angiography (CTA) confirmed multiple congenital vascular anomalies. The primary finding was esophageal and tracheal entrapment by a PRAA and left LA. Thoracoscopic transection of the LA was performed with a bipolar vessel sealing device with the aid of transesophageal endoscopy. RESULTS: Immediate improvement in attitude and absence of regurgitation were observed. The patient was discharged and subsequently reintroduced to grazing and long-stem hay, which were previously not tolerated. By 6 months post discharge, the patient's weight was 36 kg, comparable to an age-matched sibling and considered appropriate for the stage of growth. CONCLUSION: Thoracoscopic transection of the LA in sheep is a feasible treatment for esophageal compression resulting from a VRA. Surgical intervention resolved the clinical signs and allowed normal digestive rumination, restoring bidirectional esophageal function in a ruminant.

Computed tomography of suppurative and neoplastic diseases involving the canine omenta and omental bursa.

The greater and lesser omenta are fused peritoneal folds that largely delimit the omental bursa (lesser peritoneal cavity). The omental bursa is a potential space within the abdominal cavity that communicates with the greater peritoneal cavity via the omental (epiploic) foramen: it is subdivided into the omental vestibule, caudal omental recess, and splenic recess. Aims of this retrospective case series study were to describe the frequencies of CT findings of dogs with confirmed inflammatory or neoplastic disease of the omenta, omental bursa, or both. The sample included seven adult, medium-to-large breed dogs. All had fluid in the greater peritoneal cavity and 5/7 (71%) dogs also had fluid in the omental bursa. Primary suppurative inflammatory disease was present in three dogs, each dog had a large abscess with central gas in either the omental vestibule (two dogs) or caudal omental recess (one dog). Both abscesses in the omental vestibule arose from the papillary process of the caudate liver lobe and were surgically removed without complication. Neoplasia was present in four dogs and either arose from omentum (hemangiosarcoma, carcinoma) or infiltrated the omentum from an adjacent organ (splenic leiomyosarcoma, gastric adenocarcinoma). Neoplasms created mass-like tumors, infiltrative tumors, or both and had variable distribution (focal, multifocal, or locally extensive). All dogs with neoplasia were euthanized. CT signs of inflammatory and neoplastic disease overlapped, but the presence of gas might prioritize abscessation. CT signs helped decide feasibility of surgery based on extent of local invasion, especially involvement of structures passing through the porta hepatis.

Canine intrahepatic portosystemic shunts: Interlobar and intralobar classifications.

This two-part study design showed that a canine congenital intrahepatic portosystemic shunt (IPSS) may be classified by its location within a liver fissure (interlobar) or lobe (intralobar). A prospective anatomic study reviewed normal canine liver morphology and showed the CT angiography (CTA) appearance of the normal canine ductus venosus (DV), which was confirmed via dissection and literature review to be between the papillary process and left-lateral liver lobe (in the fissure for ligamentum venosum). A retrospective multi-institutional case series documented the frequency of imaging findings in 56 dogs with a single IPSS that underwent portal CTA at Cornell University or the Schwarzman Animal Medical Center between June 2008 and August 2022. An interlobar IPSS was seen in 24 of 56 (43%) dogs, all arose from the left portal branch except one. These shunts were typically near the median plane, remained interlobar throughout the course, and were nearly always (96%) craniodorsal to the porta hepatis. Four types were distinguished: patent DV (11 dogs), left interlobar (11 dogs), right interlobar (1 dog), and ventral interlobar (1 dog). Only about half (46%) were in the fissure for ligamentum venosum and therefore classified as a patent DV. An intralobar IPSS was seen in 32 of 56 (57%) dogs, most (88%) originated from the right portal branch and were in the right-lateral liver lobe (21 dogs) or caudate process (7 dogs). During canine portal CTA, documenting the interlobar or intralobar location of an IPSS might increase the consistency and validity of IPSS description.

Anatomic study of the canine bronchial tree using silicone casts, radiography, and CT.

This prospective anatomic study examined the canine lower airway lumen morphology by visual inspection, radiography, and CT of silicone casts of two dogs. Study results showed the lobar, bronchopulmonary segmental, and pulmonary lobular organization of the lungs grossly reflected in the hierarchically clustered branching structure of the bronchial tree. Study results also provided a basis for differentiating bronchial and bronchiolar patterns. Whereas images of silicone-filled bronchial lumens produced large-diameter, branching, tapering bands that radiated from the lung hilus, the pattern was different for small airways. Images of silicone-filled bronchiole lumens produced small-diameter, branching, tapering, nonradiating lines that created a speckled pattern resembling micronodules and, unexpectedly during radiography, small-diameter rings with air-filled lumens attributed to positive and negative summation shadows. Consequently, imaging patterns in dogs might be affected by pulmonary lobular morphology and might differentiate large and small airway diseases.

Mediastinal Serous Cavity Mesothelioma in Two Dogs.

The mediastinal serous cavity (MSC)-well documented but seldom recognized in the caudal mediastinum-is embryologically derived from the omental bursa. Mesothelioma arising from the MSC in two dogs is described. Both dogs presented with acute life-threatening hemorrhagic pleural effusion. Contrast computed tomography revealed a large solitary spherical-to-cylindrical tumor in the caudal mediastinum with variably thick, contrast-enhancing walls with lobular to frond-like proliferations that arose circumferentially and projected internally into a single, variably sized, fluid-attenuating lumen. The wall and lumen corresponded to the serous membrane and serous cavity of the MSC. Surgical exploration confirmed that both tumors arose from the mediastinum. Both had similar histologic findings, and special stains were necessary for definitive diagnosis. The tumor was nonresectable in one dog, and it was euthanized intraoperatively. The other survived 7 mo. An MSC mesothelioma should be considered a possible cause of hemothorax in dogs that may be detected on thoracic radiography and computed tomography. Differential diagnoses include esophageal foreign body or neoplasm, paraesophageal diaphragmatic hernia, MCS empyema, and pulmonary adenocarcinoma, with thoracic computed tomography helping to rule out foreign body and diaphragmatic hernia. For confirmed neoplasms, histochemistry and immunohistochemistry should be performed to differentiate between mesothelioma and pulmonary adenocarcinoma.

Complex central nervous system malformations in a Dutch Warmblood foal.

A neonatal Dutch Warmblood colt was evaluated for inability to stand, incoordination and intention tremor. Despite partial improvement in clinical signs during the first 4 days of hospitalization, neurological deficits remained. Magnetic resonance imaging identified a unilateral infratentorial arachnoid cyst-like lesion with ipsilateral compression and displacement of the cerebellar hemisphere, absent corpus collosum, polymicrogyria, suspect leukoencephalopathy, and noncompressive occipitoatlantal malformation. Improvement in clinical signs during the first 6 months of life suggests that horses can survive with complex congenital neurological malformations, but prognosis for athletic performance is poor. The accessibility of magnetic resonance imaging should improve the diagnostic accuracy of central nervous system disorders in neonatal foals in which congenital malformations are suspected. Euthanasia often is elected in foals with suspected congenital central nervous system disorders because of poor prognosis for athletic performance, limiting understanding of clinical progression in these cases.

Associations between styloid process sheath CT sizes and age, body weight, and breed in horses.

The styloid process sheath (SPS) is a part of the tympanic temporal bone and an incomplete bony sleeve surrounding the styloid process, tympanohyoid cartilage, and dorsal part of the stylohyoid bone. In horses undergoing head CT, we observed a range of SPS sizes and questioned whether differences were early features of temporohyoid osteoarthropathy (THO) or normal anatomic variations associated with age, body weight, sex, or breed. We hypothesized that SPS sizes were positively correlated with age and body weight, but not with sex or breed. Using a convenience population of horses that underwent head CT at our institution (2008-2017), regardless of THO status, we investigated these hypotheses in a retrospective cross-sectional study. The sample comprised 102 horses. The median SPS height was larger medially (4.3 mm) than laterally (2.4 mm) and the median width was 11.1 mm: no difference was detected between sides. Geldings had a significantly larger median SPS width (11.6 mm) than stallions (8.7 mm; P < 0.05) and mares (10.0 mm; P < 0.05). No association was detected between SPS sizes and body weight and breed. Univariate and multivariate analyses initially found significant associations between SPS heights and age. Secondary analyses performed following removal of outliers and horses <2-years old found similar but less pronounced results (annual increase in SPS heights decreased from 3.2-3.8% to 0.9-2.6%). Most associations were insignificant when investigated by age group, but the annual rate of increased size might be faster in older horses. Excessive SPS enlargement was theorized as an essential component of THO.

Selected advanced imaging techniques were unable to quantify in vivo parasitic burden in heartworm-infested dogs.

This prospective exploratory study aimed to determine whether certain noninvasive advanced imaging techniques could estimate parasitic burden in heartworm-infested dogs; a noninvasive method is needed for ethical considerations and permitting longitudinal drug studies. Three cardiac-gated and respiratory-gated 3T MRI techniques and CT pulmonary angiography (CTPA) were performed in three healthy beagles to optimize imaging techniques. Once the imaging techniques were established, a pilot study was performed to determine which one of the MRI techniques would be used in an observer comparison study. Ultimately, spoiled gradient recalled (SPGR)-cine-MRI and CTPA were performed in four and five heartworm-infested dogs, respectively. Heartworms were detected in the pulmonary arteries in all dogs during SPGR-cine-MRI and in no dog during CTPA. However, counting the number of worms was unsuccessful. In conclusion, CTPA and SPGR-cine-MRI were unable to replace necropsy for quantifying parasitic burden in heartworm-infested dogs.

Prevalence, Radiographic, and Demographic Features of Buccal Bone Expansion in Cats: A Cross-Sectional Study at a Referral Institution.

Buccal bone expansion (BBE) refers to bulbous enlargement of the periodontium in domestic cats. The origin of BBE is unknown, and some of its epidemiological, clinical, and radiographic features have not been fully characterized. The purpose of this study was to determine whether specific demographic characteristics are associated with BBE in cats; and whether BBE is associated with other relevant radiographic findings. Pertinent data were collected from archived dental radiographs and electronic medical records of 97 client-owned cats. Results showed that BBE is common in cats presented for evaluation and treatment of dental disease; that breed, sex, and age are not associated with BBE; that BBE is not associated with a pattern of horizontal alveolar bone loss/extrusion or tooth resorption; that a pattern of vertical alveolar bone loss is a typical feature of BBE; and that BBE represents a common cause of canine tooth loss in cats.

Signs consistent with syringobulbia may be detected in dogs undergoing MRI.

Syringobulbia is a pathologic condition characterized by one or more fluid-filled cavities within the brainstem. This retrospective case series describes observations in eight dogs with syringobulbia diagnosed during MRI. All dogs were adult, small-breed dogs with concurrent syringomyelia and neurologic deficits localized to sites rostral to the spinal cord, which cannot be explained by syringomyelia (eg, six dogs had vestibular signs). On MRI, the fluid-filled cavities had signal intensity characteristics like cerebrospinal fluid, were in the medulla oblongata, and were solitary in each dog. Initially, the shape of the cavity was a slit in five dogs and bulbous in two dogs. Magnetic resonance imaging was repeated in five dogs (6-55 months of age). One dog had progression of syringobulbia from slit-like to bulbous, and four dogs had unchanged slit-like syringobulbia. One dog developed slit-like syringobulbia after cranioplasty. A variety of medical and surgical treatments were performed with improvement of some but not all clinical signs. One dog died following surgery due to cardiopulmonary failure and the other seven dogs were alive at least 1 year after the initial diagnosis, which was the least time of follow-up. One surviving dog developed a unilateral hypoglossal nerve deficit 2 months after the initial diagnosis and megaesophagus 14 months later. In conclusion, detecting a fluid-filled cavity in the medulla oblongata consistent with syringobulbia is possible in dogs undergoing MRI. The cavity is likely acquired, slit-like or bulbous, progressive, or static, and might be associated with breed size and neurologic signs localized to the medulla oblongata.

Presumptive non-cirrhotic bleeding esophageal varices in a dog.

An 8-year-old male American Staffordshire terrier was admitted for evaluation of chronic episodes of ptyalism and hematemesis after exercise. Abnormalities were not detected on routine clinicopathological tests, thoracic radiography, and abdominal ultrasonography. Endoscopic examination revealed a labyrinthine network of severely distended, hemorrhagic esophageal blood vessels. Computed tomography angiography demonstrated a network of para-esophageal vessels that communicated with the celiac artery caudally and the brachiocephalic trunk cranially, consistent with a diagnosis of non-cirrhotic esophageal varices. This is a report of exercise, ptyalism, and hematemesis secondary to presumptive, non-cirrhotic, bleeding esophageal varices in a dog.

Dogs with acute myeloid leukemia or lymphoid neoplasms (large cell lymphoma or acute lymphoblastic leukemia) may have indistinguishable mediastinal masses on radiographs.

Acute myeloid leukemia is an uncommon hematopoietic neoplasm of dogs that should be differentiated from lymphoid neoplasms, such as lymphoma, because of different treatment protocols and a worse prognosis. Thoracic radiography is performed frequently in dogs with suspected hematopoietic neoplasia, and detecting a mediastinal mass often prioritizes lymphoma as the most likely diagnosis. However, we have observed a mediastinal mass in several dogs with acute myeloid leukemia and hypothesized that (1) the frequency of a mediastinal mass was higher and (2) the size of the mass was larger in dogs with acute myeloid leukemia compared to dogs with lymphoid neoplasms. In this analytical study (observational, retrospective, and cross-sectional), the sample population included 238 dogs with hematopoietic neoplasia. These dogs were divided into lymphoid (large cell lymphoma, acute lymphoblastic leukemia) and myeloid groups based on standard phenotyping tests. A mediastinal mass was detected during thoracic radiography in 73/218 (33%) and nine of 20 (45%) dogs in the lymphoid and myeloid groups (P = 0.21), respectively. The median size ratio of mediastinal mass to cardiac silhouette was 0.20 and 0.23 in the lymphoid and myeloid groups (P = 0.96), respectively. Additionally, we observed normal thoracic radiographs in 111/218 (51%) dogs in the lymphoid group and nine of 20 (45%) dogs in the myeloid group. In conclusion, acute myeloid leukemia should be considered when a mediastinal mass is detected during radiography in dogs with suspected hematopoietic neoplasia-but the presence or size of a mediastinal mass does not differentiate between myeloid and lymphoid neoplasms.

The pathogenesis of paraesophageal empyema in dogs and constancy of radiographic and computed tomography signs are linked to involvement of the mediastinal serous cavity.

The mediastinal serous cavity is a normal anatomic space in the caudal mediastinum. Aims of this anatomic and case series study were to describe the signs of pathologic expansion of the mediastinal serous cavity observed during computed tomography (CT), review the underlying anatomy, perform a literature review, and evaluate the medical records of several dogs with mediastinal serous cavity empyema (paraesophageal empyema). The mesothelial lined mediastinal serous cavity is a cranial extension of the omental bursa, separated from the peritoneal cavity by the diaphragm, in the dorsal part of the caudal mediastinum, to the right of the esophagus, between the heart base and diaphragm. In five adult, large-breed dogs with surgically and histologically confirmed paraesophageal empyema, macroscopic plant material was found at surgery in two dogs, adherence to adjacent lung was present in three different dogs, accessory lobectomy was performed in two dogs with subacute-chronic pyogranulomatous pneumonia, and one dog had concurrent pyothorax and mediastinitis, but none had esophageal abnormalities. This study expands our understanding of the pathogenesis and basis for the imaging appearance of paraesophageal empyema in dogs by clarifying the underlying anatomic structures that direct development of this condition. The term empyema accurately describes this condition because the purulent material accumulates within an existing body cavity. The study also provides initial evidence that the development of paraesophageal empyema might be due to local extension of lung disease, such as foreign body migration or pneumonia. Computed tomography was helpful for diagnosis, assessing size, and determining the spread of disease.

Evaluation of a semi-automated computer algorithm for measuring total fat and visceral fat content in lambs undergoing in vivo whole body computed tomography.

Computed tomography (CT) is a suitable tool for measuring body fat, since it is non-destructive and can be used to differentiate metabolically active visceral fat from total body fat. Whole body analysis of body fat is likely to be more accurate than single CT slice estimates of body fat. The aim of this study was to assess the agreement between semi-automated computer analysis of whole body volumetric CT data and conventional proximate (chemical) analysis of body fat in lambs. Data were collected prospectively from 12 lambs that underwent duplicate whole body CT, followed by slaughter and carcass analysis by dissection and chemical analysis. Agreement between methods for quantification of total and visceral fat was assessed by Bland-Altman plot analysis. The repeatability of CT was assessed for these measures using the mean difference of duplicated measures. When compared to chemical analysis, CT systematically underestimated total and visceral fat contents by more than 10% of the mean fat weight. Therefore, carcass analysis and semi-automated CT computer measurements were not interchangeable for quantifying body fat content without the use of a correction factor. CT acquisition was repeatable, with a mean difference of repeated measures being close to zero. Therefore, uncorrected whole body CT might have an application for assessment of relative changes in fat content, especially in growing lambs.

Transnasal, Endoscopically Guided Skull-Based Surgery by Pharyngotomy for Mass Removal from the Sphenopalatine Sinus in a Horse.

OBJECTIVE: To report a transnasal, endoscopically guided ventral surgical approach for accessing the cranial and caudal segments of the sphenopalatine sinus for mass removal in a horse. STUDY DESIGN: Case report. ANIMAL: Adult horse with acute onset blindness referable to a soft tissue mass within the sphenopalatine sinus. CLINICAL REPORT: A 7-year-old Warmblood gelding presented with a history of running into a fence and falling. No neurologic signs were identified at initial examination but acute blindness was noted 3 weeks later. On computed tomography (CT) the sphenopalatine sinus was filled with a large homogeneous mass with poor contrast enhancement that extended dorsally with thinning to the dorsal cortex of the sphenoid bone, just rostral to the entrance of the optic canals into the cranial cavity. Surgical access to the sphenopalatine sinus was achieved using a transnasal, endoscopically guided ventral pharyngotomy approach and the mass lesion was removed. A presumptive diagnosis of chondroma was made based on histopathology. The horse recovered well from surgery, and although it has not regained vision as of 6.5 years postoperatively, the disease has not progressed. CONCLUSION: Transnasal, endoscopically-guided ventral surgical access to the sphenopalatine sinus is possible in horses and may improve access in horses with disease extending caudally beyond the palatine portion of the sinus. Use of smaller diameter or specialized instruments, such as various endoscopic bone cutting instruments, and CT image guidance may improve sinus access by this route.

Comparing Intraoral Radiography and Computed Tomography for Detecting Radiographic Signs of Periodontitis and Endodontic Disease in Dogs: An Agreement Study.

OBJECTIVE: To determine whether computed tomography (CT) and intraoral radiography are interchangeable for detecting signs of periodontitis and endodontic disease in dogs. MATERIALS AND METHODS: An agreement study was performed using 40 dogs that previously underwent intraoral radiography and CT during the same anesthetic episode. Images of each tooth were examined by two blinded observers for signs of periodontitis and/or endodontic disease. Agreement between imaging modalities and between observers was assessed using the Kappa statistic. RESULTS: Agreement between modalities for detecting periodontitis in the maxillae ranged from poor to very good (κ 0.07-1.00) with 16/20 (80%) of the teeth having a score of moderate or better (κ ≥ 0.41). Agreement between modalities for detecting signs consistent with periodontitis in the mandibles ranged from poor to very good (κ 0.01-1.00) with 10/22 (45%) of the teeth having a score of good or better (κ ≥ 0.61); 50% of the disagreement was present in the incisors. Agreement between modalities for detecting signs consistent with endodontic disease in the whole mouth ranged from fair to very good (κ 0.21-1.00) with 30/42 (71%) of the teeth having a score of moderate or better (κ ≥ 0.41). Agreement between observers evaluating intraoral radiology ranged from poor to very good (κ 0.05-1) for detecting signs consistent with periodontitis and from fair to very good (κ 0.36-1) for detecting signs consistent with endodontic disease, in the whole mouth. Agreement between observers evaluating CT ranged from fair to very good (κ 0.35-1) for detecting signs consistent with periodontitis and from fair to very good (κ 0.36-1) for detecting signs consistent with endodontic disease, in the whole mouth. CONCLUSION: Performing both CT and intraoral radiography may be unnecessary to detect signs consistent with periodontitis and endodontic disease in dogs based on the amount of agreement between modalities and observers when CT images are acquired and reconstructed in 0.5 or 1 mm slice thickness, except for diagnosing periodontitis in the mandibular incisors.

CORRELATIONS AMONG ULTRASONOGRAPHIC MEASUREMENTS OF OPTIC NERVE SHEATH DIAMETER, AGE, AND BODY WEIGHT IN CLINICALLY NORMAL HORSES.

Early diagnosis of high intracranial pressure (ICP) is critical for minimizing progressive brain injury due to reduced cerebral perfusion. In people, detecting enlargement of the optic nerve sheath diameter (ONSD) by transpalpebral ultrasonography has been found to be an accurate test for high ICP. Aims of this prospective, observational, cross-sectional study were to test hypotheses that (1) ultrasonographic measurement of ONSD would be repeatable in horses, (2) have acceptable interobserver agreement, and (3) would be correlated with age and body weight. The sample population included 48 horses without clinical signs of high ICP and with varying ages and body weights. Two observers independently performed ONSD measurements in both eyes. All measurements ranged from 2.6 to 6.5 mm. The mean difference of repeated measures within observers was ≤0.1 mm and the coefficients of variation ranged from 5.0% to 8.8%. The mean difference of measures between observers was ≤0.2 mm. After correcting for performing multiple tests, no significant rank correlation (all r < 0.4 [absolute value]) was detected between ONSD and age or body weight. However, we observed smaller ONSD in foals versus adults (all P ≤ 0.002). In the foals, all observed measures of rostrocaudal and dorsoventral ONSD were <5 mm. In the adults, all observed measures of rostrocaudal and dorsoventral ONSD were ≤6.5 mm. Findings indicated that ultrasonographic ONSD measurement is a feasible test for use in horses of varying ages and sizes. Further investigation of this ultrasonographic measure as a clinical test for horse with suspected high ICP is warranted.