IMAGING DIAGNOSIS—DISCOSPONDYLITIS AND SEPTIC ARTHRITIS IN A DOG

A 6-year-old German Shepherd dog was evaluated for hind limb lameness. When a diagnosis, could not be achieved using radiography and ultrasonography, bone scintigraphy was performed to look for occult lameness or the presence of multiostic disease. Bone scintigraphy was useful in identification of increased radiopharmaceutical uptake in the thoracic spine and right coxofemoral joint, which directed further testing leading to the diagnosis of discospondylitis, septic arthritis of the coxofemoral joint, and a urinary tract infection.     

IMAGING FEATURES OF DISCOSPONDYLITIS IN TWO HORSES

Two horses with discospondylitis are described with emphasis on the imaging modalities used and their contribution to the final diagnosis and outcome. Radiographic findings were vertebral endplate lysis with sclerosis in both horses, with additional vertebral subluxation and ventral spondylosis in one horse. Ultrasonographic findings included vertebral malalignment and obliteration of the intervertebral disc by spondylotic bone in one horse and irregular endplates, a widened disc space, a hypoechoic paravertebral abscess and hypoechoic, atrophic adjacent musculature with loss of linear fiber pattern in the other horse. Bone scintigraphy excluded additional affected sites. A systematic approach is recommended when performing an ultrasound examination of the spine.     

MAGNETIC RESONANCE, COMPUTED TOMOGRAPHIC AND RADIOLOGIC FINDINGS IN A DOG WITH DISCOSPONDYLITIS

Magnetic resonance (MR), computed tomographic and radiographic imaging were conducted in a dog with discospondylitis. The MR findings were increased T2 and decreased T1 signal intensity of the soft tissues ventral to vertebral bodies, the end plates of the same vertebral bodies and the intervertebral disc, and are similar to those described in human with discospondylitis.     

VERTEBRAL PHYSITIS: A RADIOGRAPHIC DIAGNOSIS TO BE SEPARATED FROM DISCOSPONDYLITIS

A retrospective study was initiated to investigate the incidence, radiographic appearance and progression of vertebral physitis, a condition the authors propose as a separate radiographic diagnosis from discospondylitis. From 30 dogs with an initial radiographic diagnosis of discospondylitis, six dogs (five less than two years old) had radiographic signs believed to represent vertebral physitis. Bone lysis initially confined to the caudal physeal zone of affected vertebrae and sparing the vertebral endplates characterized the vertebral physitis lesions. Subsequent collapse of the caudoventral vertebral body and reactive spondylosis arising only from the caudal vertebral margins followed as the lesions progressed. By contrast, discospondylitis lesions originated as symmetric lysis of the vertebral endplates with reactive sclerosis in both vertebral bodies, and subsequent symmetric spondylosis. As a result of the differing radiographic patterns demonstrated by the physitis and discospondylitis lesions the author's also propose an alternative pathogenesis from that which is generally accepted for discospondylitis.     

RADIOGRAPHIC FINDINGS DURING RECOVERY FROM DISCOSPONDYLITIS

The diagnosis of discospondylitis is based on radiographic changes in the vertebrae. The limitations of this method are the time gap between the onset of clinical signs and the first appearance of the radiographic findings, as well as the disassociation between the clinical and radiographic signs during recovery. It is known that the radiographic changes appear only two to four weeks after the onset of clinical signs, but the characteristics of radiographic changes during recovery has yet to be documented, thus making follow-up radiographs difficult to interpret. A prospective and retrospective study was designed to document typical radiographic changes during recovery from discospondylitis. We reviewed 12 dogs that had complete and uneventful recovery with antibiotic therapy alone. Periodic follow-up radiographs and clinical examinations were conducted up to five months after the onset of clinical signs to correlate between the clinical status and radiographic changes during recovery. Although the clinical signs improved within the first 10 days of antibiotic therapy, the radiographic deterioration continued before regression and signs of radiographic recovery were noticed. This radiographic deterioration, despite successful antibiotic therapy, appeared shorter in young dogs (less than one year old) and lasted three to nine weeks in older dogs.     

LINEAR OSTEOCHONDROMATOSIS IN A CAT

A domestic shorthair cat was presented with quadriparesis and lumbar hyperesthesia that progressed over 4 months. There were linear and amorphous radiopaque masses throughout the soft tissue surrounding the long bones, vertebral bodies, ribs, pelvis, and scapula. The diagnosis of osteochondromatosis was confirmed by histopathology. Unlike previously reported patients with osteochondromatosis, most of the calcified masses in this cat were not connected to the periosteum; some were linear and were arranged parallel to the long bones involved.     

UNUSUAL HYPERPARATHYROIDISM IN A CAT

A 5 month-old, male, domestic short hair cat was presented with inappetence and vomiting. it was depressed and reluctant to move. The cat had difficulties in keeping the standing position and grossly deformed thighs. Lytic changes and disruption of normal architecture of the bone were observed, involving mainly the femoral diaphyses. An inverse Ca/P ratio and kidney failure were diagnosed. The possibility of whether the bone changes could have been related to primary or secondary renal hyperparathyroidism is discussed.     

CONGENITAL ELBOW SUBLUXATION IN A CAT

Congenital elbow luxations are responsible for 17-20% of nontraumatic lameness of the elbow joint. They are not associated with a growth disorder or trauma. Congenital elbow luxation has been observed in dogs, but no data were found about this condition in cats. In this report, we describe congenital bilateral elbow subluxation in a cat.     

SYSTEMIC ASPERGILLOSIS IN A CAT

An 8–year–old male domestic shorthair cat with partial anorexia, occasional cough and behavior change was found to have multiple pulmonary and cerebral lesions. At necropsy a diagnosis of systemic Aspergillosis was made. This report describes the clinical, radiographic and pathologic features of systemic Aspergillosis in a cat.     

SPINAL SUBARACHNOID CYST IN A CAT

A 7-year-old neutered female domestic short hair cat was presented with hind limb ataxia. A subarachnoid cyst in the T10-T11 spinal cord region was identified by myelography as a collection of contrast medium in the subarachnoid space.     

TRUE DIAPHRAGMATIC HERNIA IN A CAT

A report of a cat with a true diaphragmatic hernia in which only falciform fat had herniated is pressented. The lession was misinterpreted as a pulmonary mass. Additional radiographic studies which may have been of diagnostic benefit are briefly discussed.     

CROSSED RENAL ECTOPIA WITH FUSION IN A CAT

In humans, crossed renal ectopia is a rare, usually asymptomatic, congenital malpositioning of the kidneys, involving wandering of one or both embryonic kidneys across the midline and usually fusion with its contralateral partner. This is the first report of crossed renal ectopia in the cat. A 7-year-old, neutered male cat was presented with polyuria, polydipsia, and a palpable abdominal mass. Diagnostic investigations, including clinical pathology, survey and contrast radiography, and ultrasonography, confirmed the presence of an ectopic left kidney fused with an orthotopic right kidney, with concurrent renal failure and hypertension. Many features of crossed renal ectopia in this cat are similar to those described in humans, however the vascular supply, the presence of renal failure, and the axial rotation of the fused kidney are atypical.     

MALIGNANT PERIPHERAL NERVE SHEATH TUMOR IN A CAT

A report of a cat with a cranial tumor of nerve sheath origin is presented. The cranial mass, with a cyst-like character on presentation to the referring veterinarian suggested a benign lesion, but the clinical course was rapid and indicative of central nervous system involvement. The tumor was poorly differentiated by histologic examination, but immunohistochemistry was consistent with Schwann cell origin. Features of peripheral nerve sheath tumors in cats and other species are briefly discussed.     

DOUBLE CONTRAST GASTROGRAPHY IN THE CAT

Radiographic diagnosis of gastric mucosal disease has not been reported in the cat. This may be due to the difficulty in making these diagnoses with survey or single contrast radiography. Double contrast gastrography (DCG) allows direct visualization of gastric mucosal surfaces. The DCG technique in the cat is described, and the normal radiographic appearance is illustrated.     

PERSISTENT NEPHROGRAM IN A CAT AFTER INTRAVENOUS UROGRAPHY

An 8-year-old cat was evaluated for recurrent bouts of stranguria, hematuria and pollakiuria. Routine urinalysis, CBC and serum chemistries were unremarkable. Intravenous excretory urography was performed while the cat was sedated. The nephrogram was initially well opacified and increased in opacity during the 40 minutes that the study was performed. Ureterogram and pyelogram failed to develop. Oliguria with little excretion of the contrast medium was documented. These findings are consistent with either contrast medium associated hypotension or acute renal failure. Treatment with aggressive fluid therapy and a continuous dobutamine infusion reestablished urine output after 2 hours.     

IOHEXOL AS A GASTROINTESTINAL CONTRAST MEDIUM IN THE CAT

Iohexol was evaluated as a radiologic contrast medium in the gastrointestinal (GI) tract in cats. Three different doses (525, 700, 875 mg iodine/kg with an iodine concentration of 300 mg iodine/mL) diluted with tap water until a total volume of 10 ml/kg, were administered via an orogastric tube, to 5 cats at weekly intervals. The GI transit time was rapid and variable. Gastric emptying commenced immediately after administration of the contrast medium and was complete within 10–30 min. In each dose, iohexol reached the large intestine within 10–20 min. In 73% (11/15) of studies, the mucosal border appeared as a thin homogeneous "halo" of lucency surrounding the more opaque contents of the small intestine. Radiographic image quality of the GI tract was inadequate with the lowest dose (525 mg iodine/kg). Image quality did not deteriorate along the GI tract. Absorption of iohexol from the GI tract was observed in 40% (6/15) of examinations, where opacification of the urinary bladder was seen. No side effects were observed. lohexol should be considered as an alternative GI contrast medium in the cat when the use of other radiologic contrast media is contraindicated.     

IMAGING DIAGNOSIS—GASTRIC PNEUMATOSIS IN A CAT

Gastrointestinal foreign bodies were removed surgically from a 9‐year‐old Siamese cat. Two days later the cat became lethargic and started regurgitating. A degenerative leukocytosis and drop in packed cell volume were present. Gastric wall thickening with intramural gastric air was detected radiographically and sonographically. Gastric ulceration with a focal necrotic area was seen endoscopically. At surgery, the stomach wall was emphysematous. Clinical signs resolved following partial gastrectomy and medical management. Intramural gastric air with declining clinical course was a significant impetus to return to surgery.     

MYELOGRAPHY IN THE CAT

Metrizamide myelographic examinations were performed on five normal cats using sequential cisternal and lumbar injections at weekly intervals to determine the dose of contrast medium required, adverse effects, and quality of the myelographic study. The normal myelographic appearance in the cat is described. All spinal cords were examined histopathologically after the termination of the study, and variable mild lesions were found. Doses of 0.2 ml/kg, 0.35 ml/kg, and 0.4 ml/kg metrizantide, respectively, for lumbar, thoracolumbar, and complete spinal studies are recommended when performing lumbar injection. Recommended doses using cisternal injection for cervical, cervicothoracic, and complete spinal studies are 0.2, 0.45, and 0.5 ml/kg, respectively. Subjectively, lumbar injection produced higher-quality thoracolumbar myelograms and cisternal injection produced higher-quality cervical studies. Clinical complications during the study included one seizure following cisternal myelography and mild neurologic deficits in all cats, which resolved within 36–48 hours.     

BILATERAL ELBOW MALFORMATION IN A CAT CAUSED BY RADIO-ULNAR SYNOSTOSIS

A 9-month-old neutered male cat was referred because of left forelimb lameness. Physical examination, laboratory analysis, and radiographic examination of the entire skeleton were performed. The radiographic diagnosis was bilateral radio-ulnar synostosis with secondary elbow malformation. A comparison between clinical and radiographic findings of the cat and those described in children affected by radio-ulnar synostosis is reported. Correlations and differences are discussed.