Pulmonary adenocarcinoma with osteoblastic bone metastases in a cat

A 12-year-old male cat with depression and dyspnoea was presented for investigation. Radiography and computed tomography revealed hydrothorax and solid masses involving the sternum, ribs and thoracic vertebrae. The cat died two days after first presentation, and postmortem examination revealed lung masses and proliferative bony lesions. Histologically, a neoplastic proliferation of epithelial cells was seen in the lungs, with a large amount of collagen and deposits of cholesterin. The bone lesions were also composed of neoplastic epithelial cells and abundant calcified osteoid, without atypia. A diagnosis of pulmonary adenocarcinoma with osteoblastic bone metastases was made. This is the first reported case of osteoblastic metastases in the cat.     

Use of three-dimensional computed tomography for diagnosis and treatment planning for open-mouth jaw locking in a cat

CASE DESCRIPTION: A 2.5-year-old spayed female Persian cat was evaluated for acute inability to close its mouth. CLINICAL FINDINGS: A wry-mouth malocclusion was evident, and the right side of the mandible was longer than the left side. The right mandibular tooth row appeared to be lowered. The lower jaw was persistently maintained in an open position. The presumptive diagnosis was open-mouth jaw locking. Diagnostic imaging with computed tomography and 3-dimensional reconstruction was performed for definitive diagnosis and to achieve a better understanding of the lesions. Imaging revealed locking of the right ramus of the mandible, which was displaced ventrolaterally, causing the coronoid process to impinge on the right zygomatic arch. TREATMENT AND OUTCOME: A bilateral partial ostectomy of the rostroventral margins of the zygomatic arches with an autogenous fat graft implantation was performed. The cat recovered without complications and by the following morning was bright, alert, and responsive and eating canned cat food comfortably. One year after surgery, the owner reported that the cat had continued to function well, was eating normally, and had not had any observed locking episodes since surgery. CLINICAL RELEVANCE: Unlike radiographic imaging, computed tomography may be used to create 3-dimensional reconstructions of structures in cases of suspected open-mouth jaw locking; improve evaluation of the lesions; and improve decision-making and client education for diagnosis, treatment options, and prognosis.     

Partial lateral corpectomy for ventral extradural thoracic spinal cord compression in a cat

A 7-year-old, female spayed, domestic shorthair cat was presented for ambulatory paraparesis. No trauma history was reported. Myelography and subsequent computed tomography revealed multiple ventrally located extradural spinal cord compressive lesions possibly due to intervertebral disc disease. Compression at the level of Th3-Th4 intervertebral disc space was considered responsible for the paraparesis. The lesion was approached via a right-sided lateral partial corpectomy as described for dogs. Complete spinal decompression was achieved, as documented intraoperatively by visual inspection and palpation of the spinal canal. No surgery related complications were encountered and the cat improved gradually within 8 weeks after the procedure. At 1 year follow-up only a slight proprioceptive deficit in the right hind limb could be noted. This is the first report of partial lateral corpectomy in a cat and should encourage the use of this technique even in small patients.     

Dacryocystography in a cat with orbital pneumatosis

A 2‐year‐old neutered male European short‐haired cat was presented for a persistent discharge from the scar of previous left eye enucleation, performed 6 months prior by the referring veterinarian. A surgical exploration of the orbit was performed and retained nictitating membrane glandular and conjunctival tissues were removed. Eleven days later, the cat developed an orbital pneumatosis caused by retrograde movement of air through a patent nasolacrimal system and diagnosed by survey radiographic examination of the skull. Nasolacrimal system patency was assessed by dacryocystography performed by injection of iodinated contrast medium under pressure into the orbital cavity. Computed tomography dacryocystography confirmed the radiographic findings. The condition resolved following dacryocystography, possibly as an inflammatory response to the contrast medium. To our knowledge, this is the first case of orbital pneumatosis reported in a cat.     

Multi-detector computed tomography of an aortic dissection in a cat

Contrast enhanced, multi-detector computed tomography (MDCT) is a useful diagnostic imaging modality that has become increasingly available in veterinary medicine. Multi-planar and three-dimensional reconstructions allow accurate and comprehensive assessment of cardiac and vascular lesions with short image acquisition times. ECG-gated, contrast enhanced MDCT was used to assess the lesion extent and therapeutic options in a case of aortic dissection diagnosed in a hypertensive cat.     

Pulmonary lipoma in a dog

An eight‐year‐old, neutered, male German short‐haired pointer was presented for a chronic cough and an intrathoracic mass. Computed tomography revealed a mass with low attenuation in the right caudal lung lobe that invaded the principal bronchi. The mass was removed by right caudal and accessory lung lobectomy. The histopathological diagnosis was pulmonary lipoma. The clinical signs resolved following surgery. There was no evidence of recurrence or de novo lesions on computed tomography performed 12 months post‐surgery. To the authors’ knowledge, this is the first report of a pulmonary lipoma in a dog.     

Congenital lobar emphysema in a kitten

A five‐month‐old ragdoll cat presented with severe respiratory signs, unresponsive to medical therapy. Hyperinflation of the right middle lung lobe was diagnosed with radiography and computed tomography. Lung lobectomy following a median sternotomy led to full recovery. Histopathological analysis revealed lobar emphysema and, based on the animal's age, congenital lobar emphysema was considered the most likely diagnosis.     

COMPUTED TOMOGRAPHY OF NONANESTHETIZED CATS WITH UPPER AIRWAY OBSTRUCTION

Upper airway obstruction is a potentially life‐threatening problem in cats and for which a noninvasive, sensitive method rapid diagnosis is needed. The purposes of this prospective study were to describe a computed tomography (CT) technique for nonanesthetized cats with upper airway obstruction, CT characteristics of obstructive diseases, and comparisons between CT findings and findings from other diagnostic tests. Ten cats with clinical signs of upper airway obstruction were recruited for the study. Four cats with no clinical signs of upper airway obstruction were recruited as controls. All cats underwent computed tomography imaging without sedation or anesthesia, using a 16‐slice helical CT scanner and a previously described transparent positional device. Three‐dimensional (3D) internal volume rendering was performed on all CT image sets and 3D external volume rendering was also performed on cats with evidence of mass lesions. Confirmation of upper airway obstruction was based on visual laryngeal examination, endoscopy, fine‐needle aspirate, biopsy, or necropsy. Seven cats were diagnosed with intramural upper airway masses, two with laryngotracheitis, and one with laryngeal paralysis. The CT and 3D volume‐rendered images identified lesions consistent with upper airway disease in all cats. In cats with mass lesions, CT accurately identified the mass and location. Findings from this study supported the use of CT imaging as an effective technique for diagnosing upper airway obstruction in nonanesthetized cats.     

Differences between µCT‐imaging and conventional CT for the diagnosis of possible diseases of the middle and inner cat ear

The aim of this study was to check the relevance of using in‐vivo micro computed tomography (µCT) for the diagnosis of possible diseases of the middle and inner ear of the cat. Therefore, on the one hand, differences of the detail detectability between the two imaging methods conventional computed tomography (cCT) and in‐vivo µCT were analyzed. Six healthy cat ears were dissected and scanned several times and the obtained images were compared with each other. On the other hand, histological slices of all ears were prepared and pictures of defined anatomical structures were taken and compared with the identical sectional plane of the µCT‐images. This way it was possible to evaluate the quality and clinical limitations of the in‐vivo µCT. The results show that an in‐vivo µCT is suitable to analyze even the smallest osseous structures, such as the semicircular ducts, the spiral osseous lamina or the ossicles whereas with the help of cCT it is not possible to identify such small osseous structures because of their blurred and less detailed representation. Delicate soft tissue structures as the membranous labyrinth including hearing and vestibular organ cannot be differentiated with as well in‐vivo µCT‐ as with cCT‐images. In‐vivo µCT represent a good possibility for more detailed diagnosis of extremely fine structures which cannot be detected with cCT. Histological slices can nonetheless not be replaced by in‐vivo µCT due to a too low spatial resolution and the limitations of the in‐vivo µCT with regard to the evaluation of soft tissue dense structures.     

IMAGING DIAGNOSIS—ECTOPIC SPLEEN MIMICKING HEPATIC TUMOR WITH INTRA‐ABDOMINAL METASTASES INVESTIGATED VIA TRIPLE‐PHASE HELICAL COMPUTED TOMOGRAPHY IN A DOG

A 10‐year‐old castrated male miniature dachshund was presented with an abdominal mass. The dog had a history of splenectomy. Triple‐phase helical computed tomography was utilized, revealing a hepatic mass and multiple intra‐abdominal solid masses. In triple‐phase helical computed tomography the images, hepatic mass and two of four intra‐abdominal masses were heterogenous in all phases. Therefore, we diagnosed a malignant hepatic tumor and presumed intra‐abdominal metastases. The masses were surgically removed and were histologically composed of normal spleen tissues, findings which were consistent with ectopic spleen.     

Medial insertion of the patent ductus arteriosus characterized by computed tomography angiography in a cat and dog

Surgical ligation of a left-to-right shunting patent ductus arteriosus was attempted in two animals. In both cases, a young cat and dog, ligation was complicated by poor visualization of the ductus resulting in unsuccessful ligation. Post-operatively, both the cat and dog underwent computed tomography angiography to characterize the location and morphology of the patent ductus arteriosus. In both cases, computed tomography angiography revealed a left-to-right shunting patent ductus arteriosus with an insertion location medial to the left pulmonary artery branch compared to the typical location. We hypothesize that this atypical location resulted in a difficult surgical visualization from the left thoracotomy approach. Transvenous coil embolization of the duct from the external jugular vein was performed in both cases and resulted in successful occlusion. Variations in the medial-lateral insertion of the ductus arteriosus may have consequences for surgical intervention. If an atypical location of a patent ductus arteriosus is suspected on transthoracic echocardiography, computed tomography angiography prior to ligation may be useful to further define ductal location and help guide the surgical approach.     

COMPUTED TOMOGRAPHY-GUIDED PERCUTANEOUS BIOPSY IN THE DOG AND CAT: DESCRIPTION OF TECHNIQUE AND PRELIMINARY EVALUATION IN 14 PATIENTS

A technique for computed tomography (CT)-guided percutaneous biopsy described for use in humans was adapted to the dog and cat and is evaluated in 14 patients. Nine retrobulbar, 1 cranial mediastinal and 4 pulmonary masses and 1 hilar lymph node were biopsied in 13 dogs and 1 cat. Tissue samples sufficient for diagnosis were obtained in 12 of the 15 lesions. Diagnoses were made following cytologic (3/12) or histopathologic (3/12) evaluation or both (6/12) and included retrobulbar lymphoma, carcinoma, spindle cell sarcoma and suppurative inflammation; pulmonary carcinoma, granuloma and eosinophilic/histiocytic inflammation; nasal carcinoma, thymoma and metastatic carcinoma of a hilar lymph node. In each patient, the needle tip was identified within the lesion on the CT image. The primary limitation was non-diagnostic samples in 3 of 15 lesions due to necrosis or insufficient tissue. Complications were minor. In addition to biopsy guidance, CT imaging provided information not obtainable with fluoroscopy or ultrasonography which assisted in tumor staging and therapy planning. Although a larger number of patients and biopsy locations would be required for a thorough assessment, the free-hand technique described in this preliminary report appeared to be a safe and useful option of biopsy guidance in the dog and cat.     

A case of primary choroidal malignant melanoma in a cat

This report describes the clinical presentation, diagnosis, histological lesions, and prognosis of a primary choroidal malignant melanoma in a 15‐year‐old cat. The animal was presented for unilateral blindness. On ocular examination, a raised pigmented mass protruding from the posterior pole into the vitreous body was observed by diffuse transillumination and indirect ophthalmoscopy. Ocular ultrasound and computer tomography (CT) scan confirmed localization of the tumor to the posterior segment. The diagnosis of primary choroidal melanoma was confirmed by histopathology after enucleation. To our knowledge, this is the first reported case of a feline malignant melanoma with a primary choroidal localization without iris involvement.     

FDG PET/CT IMAGING IN CANINE CANCER PATIENTS

2‐Deoxy‐2‐[¹⁸F]fluoro‐d ‐glucose positron emission tomography/computed tomography (FDG PET/CT) is becoming increasingly available as an imaging modality in veterinary medicine. The purpose of this study was to report semiquantitative standard uptake values (SUV) of malignant and nonmalignant tissues and organs in canine cancer patients. FDG PET/CT was performed in 14 dogs including, nine mesenchymal tumors, four carcinomas, and one incompletely excised mast cell tumor. A generally higher FDG uptake was observed in carcinomas relative to sarcomas. Maximum SUV of carcinomas ranged from 7.6 to 27.0, and for sarcomas from 2.0 to 10.6. The FDG SUV of several organs and tissues, including regional brain uptake is reported, to serve as a reference for future FDG PET studies in canine cancer patients. Several potential pitfalls have been recognized in interpretation of FDG PET images of human patients, a number of these were also observed in this study.     

CHARACTERIZATION OF PHYSIOLOGIC 18F‐FDG UPTAKE WITH PET‐CT IN DOGS

We evaluated the whole body distribution of 2‐deoxy‐2‐[18F]fluoro‐d ‐glucose (¹⁸F‐FDG) in seven beagle dogs using positron emission tomography/computed tomography. The mean and maximum standard uptake values (SUV) for various tissues were computed. The SUV of the aortic blood pool was 0.65±0.19. Moderate uptake was present in brain (3.40±1.01). Mild uptake was present in orbital muscles, soft palate, laryngeal and pharyngeal region, mandibular salivary gland, myocardium, liver, pancreas, kidney, and intestine. ¹⁸F‐FDG uptake would be normally higher in these tissues because of normal physiologic activity. Mean and maximum SUV values of the eye, skeletal muscle, bone tissue, spleen, adrenal gland, stomach, tongue, gall bladder, and lung were similar to or lower than that of the aortic blood pool. These data provide a normal baseline for comparing pathologic ¹⁸F‐FDG uptake.     

Radiography, computed tomography and virtual bronchoscopy in four dogs and two cats with lung lobe torsion

This report describes the imaging features of radiography, computed tomography and virtual bronchoscopy in dogs and cats with lung lobe torsions. The medical records, thoracic radiographs and computed tomography images of four dogs and two cats with confirmed lung lobe torsions were retrospectively reviewed. Computed tomography with virtual bronchoscopy showed bronchial narrowing, collapse or occlusion in all six animals, while this was only appreciated on one radiographic examination. A tapering terminating angle of the air-filled bronchus proximal or distal to the collapsed region was seen only on computed tomography and virtual bronchoscopy in all six animals. The vesicular emphysema pattern typical of lung lobe torsion was seen on three computed tomographies but only on one radiographic examination. The lung lobe torsion-specific findings of vesicular emphysema and a proximally narrowed or occluded bronchus were more easily recognised on computed tomography and virtual bronchoscopy than with radiographs. Computed tomography slices acquired through the bronchus and lung lobe of interest in a cat or dog with possible lung lobe torsion can be reformatted into virtual bronchoscopic images that can be utilised along with computed tomography to help make a more definitive preoperative diagnosis.     

Primary mycoplasma pneumonia associated with reversible respiratory failure in a cat

A young adult cat was evaluated for respiratory failure. Diagnostic testing, including computed tomography and culture, documented a primary Mycoplasma species pneumonia. The cat was treated aggressively with supportive care, including mechanical ventilation and appropriate antibiotics including doxycycline, and made a complete recovery. This is a unique case in respect of the severity of the Mycoplasma species pneumonia as well as the cat's recovery from severe lung injury.     

Retrobulbar lymphoma associated with a ballistic foreign body in a cat

A seven‐year‐old domestic shorthair cat, adopted 5 years previously with a corneal perforation of the left eye, was presented for investigation of a left orbital mass. Computed tomography revealed a metallic foreign body within a contrast‐enhancing, heterogeneous orbital mass. Large cell lymphoma was diagnosed from a fine needle aspirate. The cat staged negatively and was treated with l‐asparaginase, prednisolone and three fractions of radiation therapy. A rapid clinical remission was obtained and the cat remained in remission for 3 years after therapy. This is the first report of large cell lymphoma likely occurring secondary to a foreign body.