Page 381 - Atlas of Small Animal CT and MRI

Intervertebral disk disease and other degenerative disorders 371

Figure 3.5.14 Lumbosacral Type II Disk Protrusion and Neuritis (Canine) MR

(a) T2, SP (b) T2, TP (c) T1, SPGR, TP

(d) T1, TP (e) T2, TP (f) T1, SPGR, TP

(g) STIR, MIP, DP (h) T1+C+FS, MIP, DP
8y MC Bull Terrier with pain referable to the lumbosacral region. Images b and c are at the level of the lumbosacral intervertebral disk.
Images d–f are at the level of the midbody of the seventh lumbar vertebra. Images g and h are thin‐slab STIR and contrast‐enhanced,
fat‐suppressed T1 thin‐slab maximum‐intensity projection (MIP) images, respectively. The lumbosacral intervertebral disk space is nar­
row, and hydrated nucleus pulposis is nearly absent (a–c: arrow). The dorsal annulus fibrosis protrudes into the vertebral canal, causing
elevation of the cauda equina (a–c: large arrowhead). Marked lumbosacral spondylosis is present, and lateralized new bone encroaches
on the lumbosacral intervertebral foramina (a–c: small arrowhead). New bone and ligamentous structures are T2 hypointense (a,b) but
have moderate T1 hyperintensity on the T1‐weighted SPGR sequence (c). The seventh lumbar spinal nerve roots are enlarged and con­
trast enhance cranial to their emergence through the intervertebral foramina (d–h: arrowheads). An L7–S1 dorsal laminectomy was
performed and documented lumbosacral stenosis from annulus fibrosis protrusion and hypertrophy of the interarcuate and dorsal
longitudinal ligaments. These changes, in conjunction with the lateral spondylosis, resulted in intervertebral foraminal stenosis and
consequent bilateral seventh lumbar spinal neuritis.