Surgical retrieval of a guide wire lost during central venous catheterization in a dog.

OBJECTIVE: To report a case of successful surgical removal of a guide wire lost during central venous catheterization. CASE SUMMARY: A 28 kg, 4-year-old female neutered mixed breed dog presented to the primary care veterinarian with diabetic ketosis. During the process of central venous catheterization, the guide wire was accidently released and the entire length of the guide wire slipped into the jugular vein. Due to the absence of nearby interventional radiology facilities, surgical intervention was proposed. An ultrasound was used to determine that the guide wire was located in the caudal vena cava extending caudally into the right internal iliac vein. Rommel tourniquets were placed around the iliac vein cranial to the bifurcation of the common iliac vein into the external and internal iliac veins. A venotomy was performed in the right common iliac vein and the guide wire was grasped with hemostats and gently removed while alternately relaxing the cranial then caudal tourniquets. During anesthesia, ventricular premature contractions were noted that varied in frequency with the dog's positioning. Postoperative color flow Doppler ultrasound evaluation of the caudal vena cava, right common, internal and external iliac veins, and right femoral vein was normal with no evidence of thrombosis. Several days postoperative the dog's diabetic ketosis and ventricular premature contractions had resolved and color flow Doppler ultrasound evaluation was normal with no evidence of thrombosis. NEW OR UNIQUE INFORMATION PROVIDED: To the authors' knowledge, this is the first reported veterinary case of loss and subsequent surgical retrieval of a central venous catheter guide wire.

Comparison of radiography and ultrasonography for diagnosing small-intestinal mechanical obstruction in vomiting dogs.

A cross-sectional study was performed on acutely vomiting dogs to compare the accuracy of radiography and ultrasonography for the diagnosis of small-intestinal mechanical obstruction and to describe several radiographic and ultrasonographic signs to identify their contribution to the final diagnosis. The sample population consisted of 82 adult dogs and small-intestinal obstruction by foreign body was confirmed in 27/82 (33%) dogs by surgery or necropsy. Radiography produced a definitive result (obstructed or not obstructed) in 58/82 (70%) of dogs; ultrasonography produced a definitive result in 80/82 (97%) of dogs. On radiographs, a diagnosis of obstruction was based on detection of segmental small-intestinal dilatation, plication, or detection of a foreign body. Approximately 30% (8/27) of obstructed dogs did not have radiographic signs of segmental small-intestinal dilatation, of which 50% (4/8) were due to linear foreign bodies. The ultrasonographic diagnosis of small-intestinal obstruction was based on detection of an obstructive lesion, sonographic signs of plication or segmental, small-intestinal dilatation. The ultrasonographic presence or absence of moderate-to-severe intestinal diameter enlargement (due to lumen dilatation) of the jejunum (>1.5 cm) was a useful discriminatory finding and, when present, should prompt a thorough search for a cause of small-intestinal obstruction. In conclusion, both abdominal radiography and abdominal ultrasonography are accurate for diagnosing small-intestinal obstruction in vomiting dogs and either may be used depending on availability and examiner choice. Abdominal ultrasonography had greater accuracy, fewer equivocal results and provided greater diagnostic confidence compared with radiography.

Associations between cardiopulmonary variables and the cerebrospinal fluid signal-void sign in small-breed dogs.

The cerebrospinal fluid (CSF) signal-void sign is a CSF signal loss, especially on T2-weighted magnetic resonance (MR) images. The CSF signal-void sign is often seen in small dogs with hydrocephalus and syringomyelia. In people, this sign is attributed to high velocity or turbulent CSF flow resulting from normal arterial pulsations, but is more pronounced in hydrocephalic patients with reduced intracranial compliance. If dogs are similar, then detection of this sign might be influenced by cardiovascular variables affected by anesthesia or related to intracranial compliance (e.g., blood pressure) or that affect CSF flow (e.g., heart rate). Therefore, the purpose of this study was to investigate whether the CSF signal-void sign is associated with these cardiovascular variables. The sample population consisted of 53 small-breed (< 15kg) anesthetized dogs undergoing spin echo, T2-weighted MR imaging of the neurocranium. Heart rate, blood pressure (systolic, mean, diastolic, pulse), and end-tidal CO2 were recorded and dogs were grouped as having a CSF signal-void sign in the mesencephalic aqueduct (19/53) or not (34/53). Normality was confirmed and t-tests used. No statistical difference was detected between groups for any of the cardiovascular variables. However, the sample size was too small to accept the null hypothesis that no difference existed between groups for any of the variables assessed. Therefore, although it is uncertain whether the investigated variables alter the frequency of detecting a CSF signal-void sign, any possible relationship does not appear strong.

Cerebrospinal fluid signal-void sign in dogs.

The cerebrospinal fluid signal-void sign is an observable signal loss from cerebrospinal fluid (CSF), especially on T2-weighted magnetic resonance (MR) images. In people, this sign is attributed to rapid CSF flow or turbulence from arterial pulsations and occurs more frequently with reduced intracranial compliance. The purposes of this study were to describe the CSF signal-void sign, document whether a similar sign occurs in dogs and investigate associations between it and other conditions. The sample population consisted of 327 dogs admitted for neurocranium evaluation using a 0.2 T system. Review of the medical records and MR images was performed to characterize the presence and location of a CSF signal-void sign, ventricular size, syringomyelia, and other lesions. A CSF signal-void sign was detected in at least the mesencephalic aqueduct in 59/327 (18.0%) dogs, including some with no morphologic brain abnormality. The majority of these dogs (45/59% or 76%) weighed < 15 kg. In two other dogs, a CSF signal-void sign was detected only in a cervical syrinx. In dogs weighing > 15 kg, a CSF signal-void sign was seen with various conditions. In 137/327 (41.9%) dogs weighing < 15 kg, the presence of a CSF signal-void sign in the aqueduct (45 dogs) was associated with syringomyelia (P = 0.0468) and increased ventricular size (P = 0.0054): syringomyelia also was associated with increased ventricular size (P = 0.0009). In conclusion, a CSF signal-void sign was seen in dogs with various conditions. In small-breed dogs, a CSF signal-void sign in the aqueduct was associated with ventricular enlargement and syringomyelia.

Postoperative susceptibility artifact during magnetic resonance imaging of the vertebral column in two dogs and a cat.

In humans that have undergone cervical diskectomy, magnetic susceptibility artifacts are often found on postoperative magnetic resonance (MR) images of the affected region. In some patients, these artifacts complicate image interpretation, while in others the artifacts lead to a false diagnosis of spinal cord compression. We describe two dogs and one cat that had susceptibility artifacts visible in postoperative MR images. In each patient, multiple, small-to-large, distinct, magnetic susceptibility artifacts were visible along the surgery site. In both dogs, interpretation was impossible and subsequently computed tomography (CT) was performed. During CT, no cause for the MR artifact was identified. The most likely source of the artifact is microscopic metal fragments from the burr, suction tip or other surgical instruments, but other possible causes include hemorrhage or paramagnetic suture material. These artifacts may cause difficulty in interpretation or suggest a clinical problem. MR imaging therefore might not be the most appropriate examination for patients following certain types of surgery due to the possibility of susceptibility artifacts. Although this artifact probably is common in the postoperative patient, the frequency that this finding will prevent accurate diagnosis is unknown.