In a three‐year prospective study, computed tomographic (CT) and surgical findings were compared for nine large breed dogs with lumbosacral stenosis. Surgically‐excised tissue was examined histologically in seven dogs and additional necropsy evaluation was performed in one dog. The CT abnormalities observed at sites of confirmed cauda equina compression were: loss of epidural fat, increased soft tissue opacity, bulging of the intervertebral disc margin, spondylosis, thecal sac displacement, narrowed intervertebral foramen, narrowed vertebral canal, thickened articular process, articular process subluxation, articular process osteophyte, and telescoped sacral lamina. The CT characteristics of lumbosacral degenerative disease and discospondylitis were similar to those described in humans. In three dogs, CT findings at the site of cauda equina compression were consistent with congenital or developmental spinal stenosis, but the method of surgical exposure precluded confirmation. Epidural fibrosis (eight dogs) and multi‐level CT abnormalities (six dogs) were identified but the cause(s) and significance were unknown.

Intraoperative Doppler ultrasonography was used to measure the effects of four experimental nerve root compression treatments (central compression, central‐plus‐lateral compression, lateral compression, and compression release) on arterial blood flow velocities in the seventh lumbar spinal ganglion of three dogs. Graphed blood flow velocity changes (change = treatment value − pretreatment value) were below baseline during the first three compression treatments and above baseline following compression release. Mean blood flow velocity changes for both central‐plus‐lateral compression and lateral compression differed (p ≤ 0.05) from changes for central compression. Changes for central‐plus‐lateral compression did not differ (p > 0.05) from changes for lateral compression. Changes among the first three compression treatments differed (p ≤ 0.05) from changes for compression release. No histologic abnormalities were identified in compressed nerve tissues, compared to contralateral controls. These findings indicate that stenosis within the L7‐S1 intervertebral foramen may cause ischemia of the L7 spinal ganglion in dogs.

In a 5-year prospective study, computed tomographic (CT) morphometry of the lumbosacral vertebral canal was performed on 42 large-breed dogs (21 controls and 21 dogs with lumbosacral stenosis). Dogs were allotted to 4 groups. Group 1 (n = 13) consisted of cadaver specimens obtained from dogs that died or were euthanatized for reasons unrelated to the spine; group 2 (n = 8) consisted of live dogs with no history of clinical signs related to the spine and with normal neurologic examination findings; group 3 (n = 10) consisted of dogs with surgically confirmed lumbosacral stenosis; and group 4 (n = 11) consisted of dogs with suspected lumbosacral stenosis that were managed conservatively. The CT scans were performed, using 5-mm contiguous slices obtained perpendicular to the vertebral canal, from the midbody of the 5th lumbar vertebra through the caudal endplate of the sacrum (L5-S3). Lumbosacral lordosis was minimized in all dogs by positioning them in dorsal recumbency with the hind limbs flexed. A tuberculin syringe calibration phantom was placed within the scanning field of view, parallel to the axis of the spine. In each dog, 11 CT slice locations within the lumbosacral spine were evaluated. At each slice location, sagittal plane diameter, dorsal plane diameter, and transverse area of the vertebral canal, vertebral body, and calibration phantom were measured, using the CT computer's software programs for distance and area calculation. Window/level settings were constant, and all measurements were made by the same operator (JCJ). Accuracy of calibration phantom CT measurements was 100% for sagittal and dorsal plane diameter and was 85% for transverse area.(ABSTRACT TRUNCATED AT 250 WORDS)

The lumbosacral spine (L5–S3) was examined by high resolution computed tomography (CT) in five canine cadaver specimens and one anesthetized dog using 5mm thick transverse slices at 5mm intervals. In each dog, anatomic features observed on CT images were confirmed by comparison with corresponding 5 mm thick anatomic transverse sections and section radiographs. CT anatomic features visualized in all dogs included the vertebral bodies, pedicles, laminae, articular processes, spinous processes, transverse processes, mammillary processes, basivertebral venous canals, vertebral foramina, intervertebral foramina, sacral wings, median sacral crest, intermediate sacral crests, lateral sacral crests, articular process joints, sacroiliac joints, internal vertebral venous plexus, epidural fat, thecal sac, L5–S3 nerve roots, and spinal nerves. Spinal ganglia, yellow ligaments, and portions of the intervertebral discs were visible in some dogs. The spinal cord, intrathecal nerve roots, dorsal and ventral longitudinal ligaments, spinal arteries, and radicular vessels were not distinguishable. Accessory processes were identified on the caudal L5 pedicles in most dogs, an observation that differed from descriptions in standard anatomy texts. Previously undescribed osseous grooves, termed “lateral recesses,” were identified in the caudal L7 vertebral foramen of all dogs.

High resolution computed tomography (CT) is a noninvasive imaging modality that has been used extensively in evaluating diseases of the human lumbosacral spine. Excellent spatial and contrast resolution, combined with multiplanar reformatting capability make high resolution CT scanners well‐suited for similar applications in dogs. Consistently good quality images can be obtained when careful attention is given to factors affecting resolution. This paper reviews and illustrates some principles of high resolution CT, and proposes a technique for regional CT examination of the canine lumbosacral spine.

High resolution computed tomography (CT) is a noninvasive imaging modality that has been used extensively in evaluating diseases of the human lumbosacral spine. Excellent spatial and contrast resolution, combined with multiplanar reformatting capability make high resolution CT scanners well-suited for similar applications in dogs. Consistently good quality images can be obtained when careful attention is given to factors affecting resolution. This paper reviews and illustrates some principles of high resolution CT, and proposes a technique for regional CT examination of the canine lumbosacral spine.

Carotid arteriography was performed in six normal goats. The same procedure was performed on these six and 112 other goats at various time intervals after placement of an arterial graft in one or both carotid arteries. An arterial catheter was introduced into the femoral artery and advanced to the origin of the brachiocephalic trunk with the aid of image‐intensified fluoroscopy. Hand‐injection of the contrast medium resulted in complete opacification of both common carotid arteries in normal animals. Opacification of one or both of the vertebral arteries was usually seen in the goats with prosthetic grafts. The left vertebral artery was seen more often than the right, and when both vertebral arteries were seen together, the left was often larger. This angiographic method proved to be reliable for opacifying both common carotid arteries from their origin on the brachiocephalic trunk to the cranial cervical region. No clinical problems were associated with either the catheterization procedure or with the permanent ligation of the catheterized femoral artery.

The short‐term neurologic and long‐term leptomeningeal effects of repeated subarachnoid administration of metrizamide at concentrations of 170 mg I/ml and 300 mg I/ml were investigated in dogs. After two months, arachnoid fibrosis of varying degrees was present in all dogs that had received metrizamide at the higher concentration. The higher concentration of met‐rizamide was more epileptogenic than the concentration of 170 mg I/ml. The presence of subarachnoid hemorrhage was not considered to play a role in the development of the arachnoid fibrosis. Veterinary Radiology Vol. 21, No. 2, 1980; pp 78–81.