IMAGING FINDINGS IN DOGS WITH CAUDAL INTERVERTEBRAL DISC HERNIATION

The radiographic and magnetic resonance imaging (MRI) findings for four dogs with herniation of the Cd1–Cd2 intervertebral disc are described. All dogs were 7 years of age at the time of presentation, with one neutered male and three neutered females. Breeds included one Beagle, one Bassett hound, and two large, mixed breed dogs. All dogs had tail pain on manipulation, two had pain during defecation, and two maintained an abnormal tail position. Three dogs had radiographs in which mineralization within the disc space was apparent. Two of these dogs also had mineralization within the vertebral canal. Three dogs underwent MRI, which was characterized by varying degrees of disc herniation and nerve root compression at Cd1–Cd2. Mobility may be a factor predisposing to disc herniation in the cranial aspect of the caudal spine. We documented that caudal disc herniation does occur occasionally in dogs and that radiography and MRI may be used to identify this disease. Caudal intervertebral disc herniation should be considered as a differential for dogs with caudal vertebral pain, pain with tail manipulation, pain during defecation, or abnormal tail carriage.     

ULTRASONOGRAPHIC FINDINGS IN 13 HORSES WITH LYMPHOMA

Ultrasonography and radiography are commonly used for staging of lymphoma in horses, however there is little published information on imaging characteristics for horses with confirmed disease. The purpose of this retrospective, case series study was to describe ultrasonographic and radiographic findings for a group of horses with a confirmed diagnosis of lymphoma. A total of 13 horses were sampled. Lymphadenopathy (8/13), peritoneal effusion (6/13), splenic (6/13), and hepatic (5/13) lesions were the most frequently identified. The predominant splenic and hepatic ultrasonographic lesions were hypoechoic nodules, organomegaly, and changes in echogenicity. Digestive tract lesions were detected in three horses and these included focal thickening and decreased echogenicity of the small (2/13) and large intestinal (2/13) wall. Thoracic lesions were predominantly pleural effusion (4/13), lymphadenopathy (4/13), and lung parenchymal changes (3/13). Enlarged lymph nodes were detected radiographically (4/13) and/or ultrasonographically (2/13) in the thorax and ultrasonographically in the abdomen (7/13) and in the caudal cervical region (4/13). Findings supported the use of abdominal and thoracic ultrasonography for lymphoma staging in horses. Ultrasound landmarks for localizing cecal and caudal deep cervical lymph nodes were also provided.     

ULTRASONOGRAPHIC FINDINGS IN DOGS AND CATS WITH GASTROINTESTINAL PERFORATION

A retrospective study was performed to evaluate the sonographic features of gastrointestinal (GI) perforation in dogs and cats. Sonographic findings in 19 animals (14 dogs and 5 cats) included regional bright mesenteric fat (19), peritoneal effusion (16), fluid-filled stomach or intestines (12), GI wall thickening (11), presence of free air (9), loss of GI wall layering (9), regional lymphadenopathy (8), reduced GI motility (7), pancreatic changes (4), corrugated intestines (4), presence of a mass (3), presence of a foreign body (3), and mineralization of the gastric wall (1). In 14 patients, "perforation" was listed as a differential diagnosis by the sonographer. Abdominal radiographs and radiographic reports were available for 14 patients. Radiographic findings were decreased serosal detail (12), free air (8), peritoneal contrast medium (1), and suspected foreign body (1). GI perforation was listed as radiographic diagnosis in eight patients, seven of which had evidence of pneumoperitoneum, and one had leakage of contrast material on an upper GI study. In 9/14 patients with radiography, "GI perforation" was listed as a sonographic diagnosis. In three patients in which free air was diagnosed sonographically, radiographs were either not available (2) or the presence of free air was not detected at presentation (1). Peritoneal fluid analysis was performed in nine patients, five of which were identified as septic inflammation, and the remaining four were classified as neutrophilic inflammation with no etiologic agent identified. The histologic or surgical diagnoses were as follows: three intestinal surgical dehiscence; one percutaneous endoscopic gastrostomy tube site leakage; one duodenal adenocarcinoma; one ileocolic lymphoma; one trichobezoar; one ascarid impaction; and one bobby pin foreign body. In the remaining 10 patients, a focal area of gastric/intestinal ulceration or transmural necrosis with perforation was identified without evidence of an underlying cause.     

MR IMAGING FINDINGS IN A DOG WITH LUMBAR GANGLION CYSTS

Intraspinal cysts of the L6-L7 and L7-S1 articular process joints in a six-year-old neutered female German Shepherd Dog were diagnosed using magnetic resonance (MR) imaging. Histopathology provided a diagnosis of ganglion cysts. Clinical, laboratory, radiographic and MR imaging findings are described. Briefly, radiographic findings revealed lumbarization of the first sacral vertebra, and fusion of the first caudal vertebra to the sacrum. In addition, spondylosis and articular process osteoarthrosis occurred at L6-L7 and L7-S1. MR imaging revealed multiple, well encapsulated structures ranging in size from 3-10 mm in diameter which were found to arise from the L6-L7 and L7-S1 articular process joints. These cysts had signal intensities that varied from hyperintense to the cerebrospinal fluid (CSF) on T1 weighted images to isointense to CSF on T2 weighted images. Decompressive surgery in conjunction with arthrodesis of these joints resulted in resolution of clinical signs. The dog remained pain-free 1 1/2 years following surgical therapy.     

IMAGING DIAGNOSIS—EXTRAHEPATIC BILIARY TRACT OBSTRUCTION SECONDARY TO A BILIARY FOREIGN BODY IN A CAT

An 11‐year‐old, neutered female British Shorthair cat was referred with a 4‐week history of abdominal pain and vomiting. Abdominal ultrasonography revealed a dilated common bile duct containing a spindle‐shaped structure with several reflecting interfaces. Differentials that were considered included an intraluminal foreign body, or helminth parasites within the common bile duct. Surgical exploration of the abdominal cavity demonstrated the presence of two grass awns obstructing the common bile duct. Anomalies of the portal vasculature were noted during surgery and were considered an incidental finding. The clinical signs resolved following surgical removal of the grass awns.     

SURVEY OF THE USE OF RADIOGRAPHY VS. ULTRASONOGRAPHY IN THE INVESTIGATION OF GASTROINTESTINAL FOREIGN BODIES IN SMALL ANIMALS

A question frequently asked by clinicians who are treating small animals suspected of having gastrointestinal foreign bodies is whether one imaging test such as survey radiography or ultrasonography is sufficient to make the diagnosis. A study was undertaken to try and answer this question. Survey abdominal radiography and ultrasonography was performed on 16 small animals (11 dogs, five cats) with clinical signs of an obstruction because of a confirmed gastrointestinal foreign body. The majority of the foreign bodies (14/16) were confirmed by surgical removal and were located in the small intestine. A gastric foreign body was retrieved endoscopically and a colonic foreign body was passed in the feces. Radiographically identifiable foreign bodies were evident in nine animals. Small intestinal overdistension was present radiographically in seven animals. Ultrasonography detected a foreign body in all 16 animals. The foreign bodies were identified by their distal acoustic shadowing and variable degrees of surface reflection. An intestinal perforation was detected sonographically but not radiographically. The value of additional sonographic findings including thickening of the gastrointestinal wall and loss of layering, free peritoneal fluid, and lymphadenopathy in these animals is discussed. The findings in this series suggest that in a small animal with a gastrointestinal foreign body, ultrasonography alone could be used to make the diagnosis and may be a more appropriate choice than survey radiography.     

APPEARANCE OF CANINE ABDOMINAL TUMORS WITH MAGNETIC RESONANCE IMAGING USING A LOW FIELD PERMANENT MAGNET

The study was carried out to evaluate the applicability of magnetic resonance imaging (MRI) in detecting tumors in the abdomen of the dog. Abdominal ultrasound and MRI were performed on 8 dogs having a mass lesion on abdominal radiography. MR images were obtained in the transverse, sagittal and dorsal planes using T1- and T2-weighted spin echo pulse sequences. There was good visual correlation of the lesion site by MRI and ultrasonography (US).     

IMAGING DIAGNOSIS—MAGNETIC RESONANCE IMAGING FINDINGS IN A CAT WITH SYSTEMIC REACTIVE ANGIOENDOTHELIOMATOSIS

A 10‐year‐old, castrated male domestic short‐haired cat was presented with an acute history of seizures, lethargy, anorexia, vomiting, and dyspnea. Magnetic resonance imaging of the brain showed multifocal areas of gray matter T2‐weighted hyperintensity. The lesions did not enhance with intravenous contrast. The cat was diagnosed at necropsy with feline systemic reactive angioendotheliomatosis, a rare vascular proliferative disorder for which a treatment has not yet been identified. This report is the first to describe associated magnetic resonance imaging changes for this disease.     

IMAGING DIAGNOSIS: MAGNETIC RESONANCE IMAGING OF A CERVICAL WOODEN FOREIGN BODY IN A DOG

This article describes the discovery of a chronic cervical wooden foreign body ventral to the left transverse processes of the cranial cervical spine using magnetic resonance imaging (MRI) in a dog that presented with chronic neck pain and lameness. The dog did not exhibit dysphagia or chronic draining tracts, the most common signs of the presumed cause, that of a penetrating oropharyngeal foreign body. The foreign body itself was represented on MR images as an oval straight-edged core within an inflammatory tissue reaction. The wood was slightly hyperintense on T2- and isointense on T1-weighted images relative to muscle. Surrounding this was a more conspicuous contrast-enhancing reactive tissue rim that was hyperintense on all pulse sequences. Adjacent musculature also exhibited diffuse edema and contrast enhancement that extended around the left cervical vertebral transverse processes and local intervertebral nerve roots. The foreign body was found to be a wooden stick upon surgical removal. MRI is an excellent method for visualizing the inflammatory tissue reactions associated with soft-tissue foreign bodies because of its contrast resolution and depiction of anatomy in multiple imaging planes.     

CLINICAL AND DIAGNOSTIC IMAGING FINDINGS IN HORSES WITH SUBCHONDRAL BONE TRAUMA OF THE SAGITTAL GROOVE OF THE PROXIMAL PHALANX

Eight sports horses with unilateral (4) or bilateral (3) forelimb or unilateral hindlimb (1) lameness had subtle radiologic abnormalities of the subchondral bone of the sagittal groove of the proximal phalanx associated with moderate or intense increased radiopharmaceutical uptake. High‐field or low‐field magnetic resonance (MR) imaging confirmed the presence of a fissure fracture or subchondral and trabecular bone trauma. Seven of eight lesions were located approximately midway between the dorsal and palmar cortices of the proximal phalanx; the eighth was sited more dorsally. Two horses underwent follow‐up MR imaging and abnormal signal intensity persisted, with little change.     

HEPATIC ABSCESSES IN 13 DOGS: A REVIEW OF THE ULTRASONOGRAPHIC FINDINGS, CLINICAL DATA AND THERAPEUTIC OPTIONS

Historical, physical examination, clinicopathologic, radiographic and ultrasonographic findings of 13 dogs with hepatic abscesses were reviewed. Liver abscessation was characterized by number, size, shape, echogenicity and location. Solitary lesions greater than 3 cm were more common than multiple ones. The abscesses were mainly poorly echogenic lesions, often with central cavitation. The shape of the lesion ranged from round to oval or irregular. Enhancement artifact, abdominal effusion, regional lymphadenopathy and hyperechoic perihepatic fat, were identified in several dogs. Ultrasound-guided aspiration was performed in 10 of 13 dogs, and confirmed abscessation with cytologic and microbiologic evaluation. Ultrasound-guided percutaneous drainage of abscesses was performed as an adjunct to medical management in four dogs.     

INTRAOPERATIVE SPINAL ULTRASONOGRAPHY IN DOGS: NORMAL FINDINGS AND CASE-HISTORY REPORTS

Intraoperative spinal ultrasonography was performed in cervical and lumbar spine of 2 and 5 normal dogs, respectively, following ventral slot technique or dorsal or hemilamenectomy. The dura was hyperechoic, while the parenchyma was hypoechoic. The subarachnoid space was anechoic. An echogenic line was present in the center of the spinal cord, as seen in human. Pulsation of the spinal cord was noted during M-mode imaging. Clinical findings of one dog with thoracolumbar disk herniation and one with thoracic vertebral fracture/subluxation confirmed the usefulness of intraoperative spinal ultrasonography for real time evaluation of spinal canal spatial abnormalities (mass lesion and degree of spinal cord compression on scanning planes) and spinal cord motion. Follow-up ultrasound examinations were possible from 6 days postoperatively.     

IMAGING DIAGNOSIS—ULTRASOUND UNCOMMON FEATURES OF AN ABDOMINAL GOSSYPIBOMA IN A DOG

An abdominal mass was incidentally detected in a 12‐year‐old, neutered female, crossed breed dog. Abdominal ultrasonographic examination showed a well‐delineated, irregular, heterogeneous mass that did not generate any distal acoustic shadowing. Transcutaneous US‐guided biopsy of the mass were nonconclusive but raised the possibility of neoplasia. Surgery discovered a mass embedded in the omentum and a large quantity of surgical sponges were identified in cut section. To the authors’ knowledge, this represents the first published case of gossypiboma casting no characteristic distal acoustic shadowing.     

IMAGING DIAGNOSIS—A LUMINAL LAMINATED DEBRIS BALL IN THE URINARY BLADDER OF A DOG

A 5‐year‐old dog presented with pollakiuria and urinary incontinence. Abdominal radiographs revealed an oval, multilayered structure with soft tissue opacity and gas lucency in the urinary bladder. Ultrasonography showed an oval luminal structure with hyper‐ and hypoechoic layers and internal reverberation artifacts. Following cystotomy, the hemisected plane showed a layered, pale whitish matrix with a gas layer around the core. Histopathological examination showed no evidence of cells, bacteria, or fungi. The core and laminae comprised fibrinous and mineral debris. A final diagnosis of a freely floating, gas‐filled laminated debris ball was made.     

IMAGING DIAGNOSIS—EXTRAHEPATIC BILIARY TRACT OBSTRUCTION SECONDARY TO A DUODENAL FOREIGN BODY IN A CAT

A 13-month-old, neutered female domestic shorthaired cat was evaluated for vomiting, anorexia, and lethargy. The cat was icteric and hyperbilirubinemic. Radiographically a partially radiolucent proximal duodenal foreign body was suspected. Ultrasonographically, there was a foreign body at the level of the duodenal papilla and dilation of the common bile duct and cystic duct; a diagnosis of extrahepatic biliary tract obstruction secondary to a duodenal foreign body was made. Sonographic findings were confirmed at surgery and a duodenal foreign body was removed. This information defines duodenal foreign body as a cause of extrahepatic biliary obstruction in cats.     

BACTERIAL ENDOCARDITIS WITH THROMBUS FORMATION AND ABSCESSATION IN A HORSE

A 2.5 year old Appaloosa stallion with progressive weight loss and a heart murmur was diagnosed as having vegetative endocarditis of the right atrioventricular valves with a mass in the right atrium. The ultrasonographic appearance of the lesion was characterized by extreme reverberation. On postmortem examination, a 9 cm diameter thrombus was found within the right atrium and auricle, occupying approximately 80% of the chamber volume. Additionally, a lenticular abscess extended throughout the parietal cusp of the right atrioventricular valve. Histologic examination revealed that the lesions were septic with numerous gram positive cocci in short chains, suggestive of Streptococcus equi , and gram negative rods.     

IMAGING DIAGNOSIS—URETHROVAGINAL FISTULA CAUSED BY A MIGRATING GRASS AWN IN THE VAGINA

A young intact female dog was presented with urinary incontinence. Abdominal ultrasound revealed the presence of hyperechoic linear structures within the cranial vagina suggestive of foreign material. A computed tomography (CT) retrograde vaginourethrogram demonstrated the presence of a fistulous tract between the urethra and vagina. A presumptive diagnosis of urethrovaginal fistula due to migration of foreign material was made. The grass awn was removed with vaginoscopic‐guided retrieval. Fourteen days later, surgical repair of the fistula and an ovariohysterectomy were done. This case report emphasizes the usefulness of CT for diagnosis and precise anatomical localization of genitourinary tract fistulas.     

IMAGING DIAGNOSIS—COMPUTED TOMOGRAPHY FINDINGS IN A DOG WITH SPONTANEOUS TRANSMURAL MIGRATION OF A TEXTILOMA INTO THE CECUM

A 3‐year‐old spayed female dog was presented with 3‐month history of severe bilateral uveitis subsequent to previous ovariohysterectomy. Physical examination revealed moderate abdominal pain. Computed tomography showed a nonobstructive heterogeneous mass‐like lesion with a speckled gas pattern (spongiform pattern) within the cecum. Exploratory laparotomy revealed a surgical swab in the lumen of the cecum with severe adhesions. Histopathological examination demonstrated a chronic inflammatory pyogranulomatous reaction to the retained swab embedded within the intestinal wall, consistent with transmural migration of the swab from the peritoneal cavity into the cecum.     

PROSPECTIVE COMPARISON OF TUMOR STAGING USING COMPUTED TOMOGRAPHY VERSUS MAGNETIC RESONANCE IMAGING FINDINGS IN DOGS WITH NASAL NEOPLASIA: A PILOT STUDY

Identification of nasal neoplasia extension and tumor staging in dogs is most commonly performed using computed tomography (CT), however magnetic resonance imaging (MRI) is routinely used in human medicine. A prospective pilot study enrolling six dogs with nasal neoplasia was performed with CT and MRI studies acquired under the same anesthetic episode. Interobserver comparison and comparison between the two imaging modalities with regard to bidimensional measurements of the nasal tumors, tumor staging using historical schemes, and assignment of an ordinal scale of tumor margin clarity at the tumor‐soft tissue interface were performed. The hypotheses included that MRI would have greater tumor measurements, result in higher tumor staging, and more clearly define the tumor soft tissue interface when compared to CT. Evaluation of bone involvement of the nasal cavity and head showed a high level of agreement between CT and MRI. Estimation of tumor volume using bidimensional measurements was higher on MRI imaging in 5/6 dogs, and resulted in a median tumor volume which was 18.4% higher than CT imaging. Disagreement between CT and MRI was noted with meningeal enhancement, in which two dogs were positive for meningeal enhancement on MRI and negative on CT. One of six dogs had a higher tumor stage on MRI compared to CT, while the remaining five agreed. Magnetic resonance imaging resulted in larger bidimensional measurements and tumor volume estimates, along with a higher likelihood of identifying meningeal enhancement when compared to CT imaging. Magnetic resonance imaging may provide integral information for tumor staging, prognosis, and treatment planning.