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.     

EVALUATION OF DIAPHRAGMATIC MOTION IN NORMAL AND DIAPHRAGMATIC PARALYZED DOGS USING M‐MODE ULTRASONOGRAPHY

Diagnosis of unilateral diaphragmatic paralysis in dogs is currently based on fluoroscopic detection of unequal movement between the crura. Bilateral paralysis may be more difficult to confirm with fluoroscopy because diaphragmatic movement is sometimes produced by compensatory abdominal muscle contractions. The purpose of this study was to develop a new method to evaluate diaphragmatic movement using M‐mode ultrasonography and to describe findings for normal and diaphragmatic paralyzed dogs. Fifty‐five clinically normal dogs and two dogs with diaphragmatic paralysis were recruited. Thoracic radiographs were acquired for all dogs and fluoroscopy studies were also acquired for clinically affected dogs. Two observers independently measured diaphragmatic direction of motion and amplitude of excursion using M‐mode ultrasonography for dogs meeting study inclusion criteria. Eight of the clinically normal dogs were excluded due to abnormal thoracic radiographic findings. For the remaining normal dogs, the lower limit values of diaphragmatic excursion were 2.85–2.98 mm during normal breathing. One dog with bilateral diaphragmatic paralysis showed paradoxical movement of both crura at the end of inspiration. One dog with unilateral diaphragmatic paralysis had diaphragmatic excursion values of 2.00 ± 0.42 mm on the left side and 4.05 ± 1.48 mm on the right side. The difference between left and right diaphragmatic excursion values was 55%. Findings indicated that M‐mode ultrasonography is a relatively simple and objective method for measuring diaphragmatic movement in dogs. Future studies are needed in a larger number of dogs with diaphragmatic paralysis to determine the diagnostic sensitivity of this promising new technique.     

IMAGING DIAGNOSIS—CANINE THORACIC MESOTHELIOMA

A 12-year-old neutered female Pembroke Welsh Corgi had a 2-month history of a progressive, productive cough nonresponsive to therapy. Mild pleural effusion, right middle lung lobe collapse, and multiple subpleural nodular lesions were detected in thoracic radiographs and computed tomography (CT) images. Histopathologic diagnosis of the pleural nodules was mesothelioma. Mesothelioma should be considered in patients where pleural masses are detected in radiographs or CT images.     

IMAGING DIAGNOSIS—NECROTIZING MENINGOMYELITIS AND POLYARTHRITIS

A vaccinated 2-year-old female neutered Weimaraner had bilateral pelvic limb ataxia that progressed over 12 h. The dog became nonambulatory, with signs of pain on palpation of the lumbar spine. The dog also developed multiple joint effusions. On magnetic resonance (MR) imaging, there was a diffuse, asymmetric T2-hyperintensity in the thoracolumbar spinal cord which was characterized by contrast enhancement. Lumbar cerebrospinal fluid (CSF) analysis had an elevated white blood cell count and protein. On the basis of MR images and CSF analysis, a presumptive diagnosis of diffuse myelitis was made. The dog became paraplegic and was euthanized. Postmortem examination confirmed the presence of myelitis with vasculitis and nonerosive polyarthritis.     

SELECTIVE ABDOMINAL ANGIOGRAPHY AS A DIAGNOSTIC METHOD FOR DIAPHRAGMATIC HERNIA IN THE DOG: AN EXPERIMENTAL STUDY

Difficulty in recognition of some diaphragmatic hernias in dogs have stimulated the authors to develop a diagnostic method consisting of selective angiography of the cranial mesenteric and celiac arteries. The basis for the experimen was that each herniated visceral organ is usually displaced with its vessels. The experiment was carried out on 14 mongrel dogs. Four dogs served as controls. Different kinds of diaphragmatic hernias were surgically created in 10 dogs. Survey abdominal radiographs, gastrointestinal tract contrast studies and selective abdominal angiography were performed 14 days later. In angiograms of dogs with omental diaphragmatic hernias, displacement of branches of the left gastroepiploic artery into the thorax was seen. In angiograms of dogs with hepatic diaphragmatic hernias, branches of the common hepatic artery were seen to enter the thorax. In dogs with herniated small intestine, the jejunal branches of the cranial mesenteric artery were seen entering the thorax. Potential possibilities of selective abdominal angiography for diagnosis of diaphragmatic hernias are discussed.     

IMAGING DIAGNOSIS—CONGENITAL VENOUS ANEURYSM OF THE LEFT EXTERNAL JUGULAR VEIN

Primary congenital jugular vein aneurysms are rare with only one prior report in a canine patient. Herein, we describe an 18-week-old Flat Coated Retriever dog in which ultrasound was used to diagnose a primary congenital external jugular vein aneurysm with concurrent dilatation of the internal jugular vein. The aneurysm was successfully removed and the dog remains disease free 24 months postoperatively. Histopathologic analysis was used to validate the ultrasound-based diagnosis.     

IMAGING DIAGNOSIS—HYPEROSTOSIS ASSOCIATED WITH MENINGIOMA IN A DOG

A 5-year-old neutered male Beagle mix dog had a 5-day history of generalized tonic-clonic seizures. Before the seizures, the dog had a 1-2-month history of progressive right hemiparesis. In computed tomography images, a presumed extraaxial mass with hyperostosis and destruction of the skull covering the mass were identified. Surgical excision was performed and the histopathologic diagnosis was meningioma. Hyperostosis is frequently associated with feline meningioma, but this report documents that hyperostosis may also occur secondary to meningioma in the dog.     

IMAGING DIAGNOSIS—COMPLEX INTRAHEPATIC PORTOSYSTEMIC SHUNT IN A DOG

An unusual form of congenital intrahepatic portosystemic shunt was identified in a 3½-month-old female Labrador Retriever with neurologic signs. Ultrasonography and contrast-enhanced computed tomography were used to characterize the shunt morphology. An unusual, looping right-divisional shunt connected back to the portal vein that formed an ampula in the right-central portion of the liver. An irregularly shaped window-like opening connected the combined right-divisional loop and aneurysmal portal vein, and the caudal vena cava, while this vascular pool gradually fused more cranially. Imaging features of this complex vascular anomaly, which has not been previously reported, are presented.     

IMAGING DIAGNOSIS—PULMONARY INTERSTITIAL EMPHYSEMA IN A DOG

In humans, pulmonary interstitial emphysema is most frequently seen in ventilated preterm newborns with severe lung disease; it is less frequently reported in adults. We report on a mature dog with pneumopathy that underwent computed tomography (CT) imaging to further characterize the lung disease. A bronchiolar pattern and lobar opacification were seen on the CT images. Moreover, gas was detected along the course of the pulmonary vessels, presumably in the interstitium, as seen in pulmonary interstitial emphysema in humans. Sever lung disease and/or hyperventilation during anesthesia could be a possible explanation of pulmonary interstitial emphysema in this dog.     

IMAGING DIAGNOSIS—ULTRASOUND-GUIDED ETHANOL SCLEROTHERAPY FOR A SIMPLE RENAL CYST

Solitary renal cysts are benign and in the majority of instances asymptomatic and do not require treatment. Nevertheless, treatment may be required if abdominal discomfort or pain, hypertension, infection or renal outflow obstruction occur. Under these circumstances, percutaneous management of the cyst is the easiest and fastest procedure, and no major complications are generally encountered. In this report we describe a patient with a solitary renal cyst treated successfully by a single injection of ethanol into the cyst. The sonographic appearance of the cyst changed from a well-defined hypoechoic structure to an ill-defined hyperechoic region. Canine renal cysts may be successfully managed in some instances by a single ethanol injection.     

CONTRAST HARMONIC IMAGING OF THE NORMAL CANINE SPLEEN

The purpose of this study was to assess the perfusion pattern and perfusion dynamics in the normal canine spleen using contrast harmonic imaging. Twenty-five dogs without clinical or ultrasonographic evidence of splenic disease were studied. Twenty-three dogs were scanned with only manual restraint; two dogs were sedated with buprenorphin. All dogs received an intravenous bolus of a microbubble contrast medium (SonoVue). The perfusion pattern during the blood pool phase represented a skewed bell-shaped curve. A tissue-specific late phase, similar to humans, was not observed. Time/intensity curves were generated for a selected region. Mean average-derived peak intensity (PI) was 6.6dB, mean time to peak intensity calculated from the initial rise (TTP) was 25.6 s and mean area under the curve (AUC) was 523.6 dBs. If dogs were divided into two body weight groups (< or =15 and >15 kg body weight), average derived peak intensity area, time to peak intensity, and area under the curve were lower for the smaller dogs than for the larger animals. However, differences were not statistically significant (P = 0.2, 0.05, and 0.08, respectively). No significant association was found between hematocrit, hemoglobin concentration, red blood cell count, blood pressure, heart rate, age, gender, and the perfusion variables. In conclusion, these baseline data may prove useful in the evaluation of dogs with diffuse or focal splenic disease.     

IMAGING DIAGNOSIS—BILATERAL ADRENAL ADENOMAS AND MYELOLIPOMAS IN A DOG

A 10-year-old neutered female Pug was evaluated for a left adrenal mass detected previously by ultrasonography. Using computed tomography, a fat-attenuating, rim-enhancing left adrenal mass and a homogeneous, soft-tissue attenuating, intensely enhancing right adrenal mass were found. A left adrenalectomy and right adrenal biopsy were performed and the final diagnosis was bilateral adrenal adenomas and myelolipomas. Myelolipomas are rare, benign, endocrinologically inactive tumors composed of well-differentiated adipose tissue and a variable amount of hematopoietic cells of both lymphatic and myeloid lineages, which may account for the different appearance on tomographic images.     

IMAGING DIAGNOSIS—MAGNETIC RESONANCE IMAGING FEATURES OF A CEREBRAL HEMANGIOBLASTOMA IN A DOG

The magnetic resonance (MR) imaging features of a cerebral hemangioblastoma in a 9‐year‐old dog are described. Imaging revealed a well‐defined contrast‐enhancing lesion of the rostral forebrain that appeared extraparenchymal. Histopathology of the excised mass showed clusters of small blood vessels interspersed with interstitial cells staining positive for neuronal specific enolase, features consistent with a cerebral hemangioblastoma; the mass also appeared intraparenchymal after further immunohistochemistry study. This neoplasm should be considered a rare differential diagnosis for intracranial masses in dogs.     

IMAGING DIAGNOSIS—DEGENERATIVE INTRASPINAL CYST ASSOCIATED WITH AN INTERVERTEBRAL DISC

A 6-year-old neutered male Rottweiler had chronic episodic signs of thoracolumbar pain and inability to stand that did not improve after rest and nonsteroidal antiinflammatory medication. In magnetic resonance images, an extradural mass was identified between the spinal cord and the T13/L1 intervertebral disc; the mass was compressing the cord in a dorsoventral direction. The lesion had a low signal intensity rim that enhanced slightly after gadolinium administration, and contents with similar signal intensity to cerebrospinal fluid. The lesion was removed surgically by severing its attachments to the annulus fibrosus. The histologic diagnosis was degenerative intraspinal cyst. The origin of such cysts, and their relationship to synovial and ganglion cysts is discussed.     

IMAGING DIAGNOSIS—LEFT RETROCAVAL URETER AND TRANSPOSITION OF THE CAUDAL VENA CAVA IN A DOG

Retrocaval ureter and transposition of the caudal vena cava are each, rare developmental anomalies. We describe the usefulness of static fluid magnetic resonance urography and dynamic contrast-enhanced magnetic resonance urography in the diagnosis of these anomalies. Basic techniques, benefits, and drawbacks of magnetic resonance urography are presented.     

QUANTITATIVE CONTRAST HARMONIC ULTRASOUND IMAGING OF NORMAL CANINE LIVER

Eight adult dogs with no evidence of liver disease, weighing between 8 and 25 kg were imaged after injection of a microbubble contrast medium using harmonic ultrasound imaging. All dogs received three separate bolus contrast injections, and six dogs also received three separate constant rate infusions each. Time/Mean Pixel Value curves were generated for selected regions of the liver. Upslope, downslope, baseline, peak, change, and time to peak were calculated. For bolus injection (averaging all subjects), upslope was 3.85 +/- 1.50 Mean Pixel Values/s, downslope was -0.71 +/- 0.30 Mean Pixel Values/s, baseline was 72.38 +/- 17.82 Mean Pixel Values, peak was 120.26 +/- 17.44 Mean Pixel Value, change from baseline to peak was 47.88 +/- 6.92 Mean Pixel Values, time to peak (from injection) was 22.88 +/- 6.79 s, and time to peak (from first upslope) was 13.88 +/- 1.55 s. Data acquisition and analysis from constant rate infusions was more cumbersome than for bolus, and results were less repeatable. There were significant differences (p < .005) in upslope, downslope, peak values, and time to peak between the two methods. These baseline data may prove useful in the evaluation of dogs with diffuse hepatic disease.     

IMAGING DIAGNOSIS—URINARY OBSTRUCTION SECONDARY TO PROSTATIC LYMPHOMA IN A YOUNG DOG

A 3-year old, intact male Doberman pinscher was examined at the Foster Hospital for Small Animals at Tufts University for a 2-week history of stranguria, dyschezia, and weight loss. Ultrasonographically, there was bilateral hydronephrosis, right-sided hydroureter, hepatosplenomegaly, symmetric mild prostatomegaly, and a distended urinary bladder. Fine needle aspirates and biopsies of the prostate yielded a diagnosis of lymphoma. Lymphoma is a rare cause of prostatomegaly in the dog. Sonographic findings are nonspecific; fine needle aspirates or biopsies are needed to ascertain the diagnosis.