Computed tomographic myelography for assessment of the cervical spinal cord in ataxic warmblood horses: 26 cases (2015–2017)

Abstract

OBJECTIVE To quantify the degree of dural compression and assess the association between site and direction of compression and articular process (AP) size and degree of dural compression with CT myelography. ANIMALS 26 client-oriented horses with ataxia. PROCEDURES Spinal cord-to-dura and AP-to-cross-sectional area of the C6 body ratios (APBRs) were calculated for each noncompressive site and site that had > 50% compression of the subarachnoid space. Site of maximum compression had the largest spinal cord-to-dura ratio. Fisher exact test and linear regression analyses were used to assess the association between site and direction of compression and mean or maximum APBR and spinal cord-todura ratio, respectively. RESULTS Mean ± SD spinal cord-to-dura ratio was 0.31 ± 0.044 (range, 0.20 to 0.41) for noncompressive sites and 0.44 ± 0.078 (0.29 to 0.60) for sites of maximum compression. Sites of maximum compression were intervertebral and extra-dural, most frequently at C6 through 7 (n = 10), followed by C3 through 4 (6). Thirteen horses had dorsolateral and lateral compression at the AP joints, secondary to AP (n = 7) or soft tissue proliferation (6). Site significantly affected direction of compression, and directions of compression from occiput through C4 were primarily ventral and lateral, whereas from C6 through T1 were primarily dorsal and dorsolateral. No linear relationship was identified between mean or maximum APBR and spinal cord-to-dura ratio. CONCLUSIONS AND CLINICAL RELEVANCE CT myelography may be useful for examination of horses with suspected cervical compressive myelopathy. Degree of compression can be assessed quantitatively, and site of compression significantly affected direction of compression.

When radiography and ultrasonography are not enough: the use of computed tomography and magnetic resonance imaging for equine lameness cases

“…Spinal cord compression, subarachnoid space narrowing, articular process enlargement, intervertebral foramen narrowing, osteoarthritis, osteochondral fragmentation, and intervertebral disc disease have all been diagnosed using plain or myelographic CT (ie, CT after injection of positive contrast material into the subarachnoid space). [126][127][128][129][130] In many cases, radiography or radiographic myelography is not sufficient to make a complete diagnosis (Figure 5). 126,127 The diagnosis of cervical stenotic myelopathy (CSM) using CT provides a good example of how CT adds to the diagnostic toolbox.…”

“…[131][132][133][134][135] CT myelography can assess the spinal cord more fully, as lateral compression can be identified in addition to the dorsoventral compression that can be identified with a radiographic myelogram. 126,129,130 It is hoped that future research investigating the association between CT findings, clinical signs, and histologic lesions of the spinal cord will lead to improved decision criteria for CSM. It is important to note that most CT scanners are unable to accommodate the degree of flexion and extension typically obtained during a radiographic myelography study, so in the opinion of this author and others, it is most appropriate to combine CT and radiographic myelography.…”

Characteristic computed tomographic myelography findings in 23 Thoroughbred horses

“…Therefore, contrast agent injection into the subarachnoid space is necessary to delineate the dura mater and pia mater. So far, CT myelography enables the most accurate diagnosis of CVSM in live horses [ 10 , 14 , 18 , 21 ]. However, previous studies on CT myelography included various breeds of horses [ 10 , 14 , 21 ], not specific for Thoroughbred breed.…”

Investigation of a contributing factor for cervical vertebral stenotic myelopathy using computed tomography for measuring the cervical vertebral volume

“…Type 1 is characterized by dynamic compression of the cranial portion of the cervical spinal cord (from C2–C3 to C3–C4) that generally affects young horses (8–15 months). Dynamic compression is caused by vertebral malformation and/or malarticulation leading to dynamic instability of the cervical vertebrae [ 6 , 9 , 10 ]. In contrast, type 2 is characterized by static compression of the caudal portion of the cervical spinal cord (from C5 to C7) that generally affects older horses (1–4 years).…”

“…In contrast, type 2 is characterized by static compression of the caudal portion of the cervical spinal cord (from C5 to C7) that generally affects older horses (1–4 years). Static compression is caused by cervical vertebral osteoarthritis and/or thickening of soft tissue [ 1 , 9 ].…”