Thrall chapter 15 MRI and CT features of canine and feline spinal disease

Question 1

1) What is the anatomical structure labelled ‘1’?
a) Interarcuate ligament
b) Dorsal longitudinal ligament
c) Intercapital ligament
d) Ligamentum flavum

Answer 1

c
meningiovertebral ligament on top of the dorsal longitudinal ligament, the dorsal ligament is thickest in the c spine (more lateralised extrusions here)

Question 2

2) Which structure reduces the likelihood of a dorsal disc protrusion between T2-T11
a) Interarcuate ligament
b) Dorsal longitudinal ligament
c) Intercapital ligament
d) Ligamentum flavum

Answer 2

c

Question 3

3) What type of joints are the articular process joints of the vertebrae?
a) Synarthrodial
b) Amphiarthroidal
c) Diarthrodial
d) Cartilaginous

Answer 3

C

Question 4

Define synarthroidal (type of joint)

Answer 4

In fibrous joints (synarthrodial joint) the bones are joined by fibrous tissue, namely dense fibrous connective tissue, and no joint cavity is present. The amount of movement allowed depends on the length of the connective tissue fibers uniting the bones.
- a fibrous joint

Question 5

Define Amphiarthroidal

Answer 5

An amphiarthrosis is a joint that has limited mobility. An example of this type of joint is the cartilaginous joint that unites the bodies of adjacent vertebrae. Filling the gap between the vertebrae is a thick pad of fibrocartilage called an intervertebral disc
A cartilaginous joint

Question 6

Define Diarthrodial

Answer 6

A diarthrosis joint is a freely moving joint characterized by its mobility and joint cavity within a synovial membrane encased in the joint capsule.

Question 7

5) Why is the normal nucleus pulposus hyperintense on T2w images?
a) Because of the short T2 relaxation time of water in the nucleus
b) Because of the long T2 relaxation time of water in the nucleus
c) Because of the short TE and TR times
d) Rotation of water occurs near the Larmor frequency

Answer 7

b, fat is closer to the Larmor frequency

Question 8

6) What percentage of dachshunds have vertebral transitional anomalies?
a) 5%
b) 10%
c) 20%
d) 30%

Answer 8

b

Question 9

7) In chondrodystrophic dogs, acute disc herniation can lead to what CT appearance? (could be more than one)
a) Hypoattenuating material causing cord compression.
b) Diffuse less hyperattenuating (apx 60HU) less severe cord compression
c) Hyperattenuating (700HU) herniated disc material
d) A large focal amount of markedly hyperattenuating disc material (200HU) compressing the spinal cord

Answer 9

b,d (c is chronic due to further mineralization)

Question 10

8) Epidural haemorrhage associated with disc extrusion is more common in which region?
a) Caudal Cervical
b) Cranial Thoracic
c) Thoracolumbar junction
d) Caudal Lumbar

Answer 10

d

Question 11

9) Meningeal contrast adjacent to extruded extradural disc material occurs in what percentage of patients?
a) 40%
b) 25%
c) 60%
d) 15%

Answer 11

A

contrast enhancement of the compressive extradural disc material occurs in approximately 50% of dogs with disc extrusion

Question 12

10) Which of the following is not a characteristic of lumbosacral stenosis
a) Intervertebral disc degeneration and protrusion
b) Hypertrophy of the articular process joint capsule and interarcuate ligament
c) Bone proliferation of the dorsal vertebral bodies
d) Vertebral subluxation

Answer 12

c- bone proliferation of the vertebral bodies is not correct, bone proliferation of the articular processes and vertebral end plates is correct

Question 13

11) What type of disc disease is shown in the images below?
a) Acute compressive hydrated nucleus pulposus extrusion
b) Acute non-compressive nucleus pulposus extrusion
c) Hansen type II IVDD
d) Hansen type I IVDD

Answer 13

a

Question 14

12) Which of these is not a prognostic factor used to assess the likelihood of a successful outcome in dogs with ANNPE?
a) Severity of neurological signs at presentation
b) Intramedullary contrast enhancement over the affected site
c) Percentage cross-sectional area of the intramedullary lesion on T2W images
d) Presence of intramedullary haemorrhage

Answer 14

b 33% of dogs with ANNPE have unsuccessful outcomes

Question 15

13) From the paper by Bonelli et al, 2021 which of the following is incorrect regarding their findings in dogs with osseous associated cervical spondylomyelopathy?
a) Intervertebral disc degeneration was seen in 80% of dogs
b) Dogs with multiple sites of spinal cord compression were more likely to have severe spinal cord compression
c) There was a weak correlation between neurologic grade and severity of spinal cord compression and the number of affected sites
d) It more commonly affected female giant and large breed dogs.

Answer 15

d, males more affected.

Question 16

14) In cats, what is the only reported cause of ischaemic myelopathy?
a) Thromboembolism
b) Fibrocartilaginous embolism
c) Neoplastic embolism
d) Septic embolism

Answer 16

B
The most common cause of spinal cord ischemia and infarction in dogs and cats is fibrocartilaginous embolism from the nucleus pulposus of the intervertebral disc.86,87,230–235 In cats, hyaline degeneration of the ventral spinal artery has also been reported as a predisposing factor In dogs other causes include thromboembolism; a hypercoagulable state; vasculopathy; and parasitic, septic, or neoplastic embolization

Question 17

1) Which of the following is false regarding subarachnoid diverticulae?
a) Most commonly dorsal or dorsolaterally located
b) Rottweilers are likely predisposed to thoracolumbar diverticula
c) Pugs have a high incidence of subarachnoid diverticula
d) The most common locations are cranial cervical or caudal thoracic

Answer 17

1) B- cervical in rottweilers

Question 18

2) Which two categories of spinal dermoid sinuses are associated with neurological signs?
a) Type II: more superficial tract with deep fibrous strand connecting to the supraspinous or nuchal ligament
b) Type III: superficial tract with no connection to the supraspinous or nuchal ligament
c) Type IV: deep tract that extends to the supraspinous or nuchal ligament and continues deeper as a fibrous strand that connects to the dura mater
d) Type VI: deep tract that extends to the supraspinous or nuchal ligament and continues deeper as a fibrous strand that connects to the dura mater

Answer 18

C,D

Question 19

3) Intramedullary spinal tumours are usually what type (can be more than one)?
a) Nerve sheath tumours
b) Astrocytomas
c) Meningiomas
d) Ependymomas

Answer 19

3) B,D or lymphoma or mets

Question 20

4) In cats which is the most common intradural extramedullary neoplasia?
a) Lymphosarcoma
b) Meningioma
c) Peripheral nerve sheath tumour
d) Mast cell tumour

Answer 20

A
it is also the most common extradural tumour in cats and most commonly has an extradural location

Question 21

5) Which is the most likely location of this mass?
a) Extradural
b) Intradural- extramedullary
c) Intramedullary

Answer 21

B

Question 22

6) According to cordle et al., 2023 which of the following is true?
a) MRI features can predict the onset of myelomalacia after acute intervertebral disc extrusion
b) MRI features can support a diagnosis of progressive myelomalacia in dogs with clinical evidence of the disease
c) Length of T2W hyperintense spinal cord change and HASTE signal loss were not significantly associated with clinically evident progressive myelomalacia

Answer 22

6) B. c is the opposite and it is statistically significant.

Question 23

7) In what percentage of patients with FCE are no changes seen on MRI?
a) 15%
b) 80%
c) 50%
d) 20%

Answer 23

D

Question 24

8) A lesion length to vertebral length ratio greater than XX has a sensitivity of 100% in predicting a poor clinical outcome for cases of ischaemic myelopathy?
a) 2
b) 2.5
c) 1.5
d) 1.8

Answer 24

A

Question 25

true or false, in cases with disc extrusion and extensive epidural haemorrhage, contrast enhancement of the haemorrhage is uncommon?

Answer 25

False: Contrast enhancement of epidural hemorrhage is common, although it is not associated histopathologically with actual inflammation. In some dogs, these secondary epidural changes can mask the extruded disc material. Altogether, these features can cause erroneous diagnosis of a tumor, and this variability needs to be taken into account when interpreting MR images in dogs with acute neurologic presentation.

Question 26

Changes in signal intensity of the paraspinal muscles can be seen in dogs with disc extrusion. what causes this?

Answer 26

patchy T2W/short tau inversion recovery (STIR) hyperintensities, and T1W hypointensities with variable contrast enhancement. They correlate with areas of muscle fiber degeneration, edema, inflammation, and necrosis.

Question 27

in dogs with IVDE Areas of intramedullary T2 hyperintensity that exceed the length of XXX on sagittal images have been associated with a poor outcome in approximately 50% of patients

Answer 27

L2 This feature has been reported to be a better predictor of poor outcome than loss of deep pain perception, and it is independent from the severity of neurologic signs at presentation.

Question 28

Tarlov cysts originate from a) close to the ventral nerve root and ganglion sheath b) from the dorsal nerve root and ganglion sheath c) from the articular process joints d) from the intervertebral disc

Answer 28

B from the dorsal nerve root and ganglion sheath, close to the point where the pia and arachnoid membrane differentiate into endoneurium and perineurium they are extradural lesions filled with CSF and contain neural structures pertaining to the nerve root and ganglion

Question 29

are dermoid cysts and sinuses or epidermoid cysts and sinuses more heterogeneous on mri?

Answer 29

Dermoid cysts and sinuses differ from epidermoid cysts because the dermoid cyst contains other features of skin, such as sweat glands, hair follicles, and sebaceous glands. epidermoid cysts usually o ly contain squamous epithelium (radiopaedia)

Question 30

which term is preferred? a) synovial cyst b) articular process cyst c) ganglion cyst

Answer 30

B as although they are different, they cannot be distinguished based on imaging alone

Question 31

what are the t1, t2 and GRE characteristics of myelomalacia?

Answer 31

t2 hyper, t1 iso (sometimes hypo) can have signal voids on t2 showing haemorrhage

Question 32

regarding ascending/ descending myelomalacia, A length of CSF signal attenuation on HASTE/SSFSE pulse sequences (“T2-myelogram”) >XXX times the length of L2 vertebral body has also been reported as a predictive MRI criterion

Answer 32

7.4 Studies have suggested that in dogs with thoracolumbar disc herniation, a longitudinal extent of spinal cord parenchyma T2W hyperintensity higher than 4.5 to 6 times the length of L2 vertebral body could be a predictor of developing ascending/descending myelomalacia Another recent study found that the length of parenchymal T2 hyperintensity was not a useful predictor for future development of myelomalacia in dogs with severe neurologic deficits who are not exhibiting clinical signs of myelomalacia. Absence of T2W spinal cord hyperintensity, however, does not rule out future development of myelomalacia particularly if imaging occurs less than 24 hours after onset of paraplegia. . both are in the book.

Question 33

what are the two most common intradural extramedullary tumours?

Answer 33

meningioma, nerve sheath tumour

Question 34

which are the most common extradural tumours in dogs

Answer 34

osteosarcoma, chondrosarcoma

Question 35

which location are nephroblastomas most commonly? a) extradural b) intradural extramedullary c) intramedullary d) l4-7 e) T10-L2 f)l2-l4

Answer 35

B, E It is thought that the tumor arises from ectopic embryonic remnants of renal tissue. A single mass is usually present, although there are rare reports of intraspinal metastases the tumour can invade the spinal cord and appear intrmedullary

Question 36

true or false, ependymomas are the most common intramedullary spinal cord tumour in dogs?

Answer 36

true. followed by astrocytoma, and less commonly nephroblastoma, chordoma, oligodendroglioma, and teratoma astrocytomas more common in cats (but very rare) and more common in cervical spine. cats- lymphoma!

Question 37

the three most common spinal tumours that can involve several compartments of the vertebral canal are

Answer 37

histiocytes sarcoma, lymphoma, haemangiosarcoma Histiocytes are a category of leukocytes that occur in many tissues throughout the body. They are derived from stem cell precursors and differentiate into cells of the monocyte/macrophage lineage or dendritic cell lineage Histiocytic sarcoma is due to neoplastic transformation of interstitial dendritic cells, with the exception of a hematophagocytic variant, which occurs within the splenic red pulp and arises from macrophages

Question 38

which has not been reported regarding vertebral haemangiosacroma a) involvement of several adjacent vertebra (segmental) b) intradural extramedullary location being the least common location c) intramedullary HSA being more likely to be the primary tumour d) heterogeneous signal with signal voids on t2*

Answer 38

C- intramedullary is more likely metastatic

Question 39

what mri features can be supportive of ascending/ descending myelomalacia?

Answer 39

Studies have suggested that in dogs with thoracolumbar disc herniation, a longitudinal extent of spinal cord parenchyma T2W hyperintensity higher than 4.5 to 6 times the length of L2 vertebral body could be a predictor of developing ascending/descending myelomalacia. A length of CSF signal attenuation on HASTE/SSFSE pulse sequences (“T2-myelogram”) >7.4 times the length of L2 vertebral body has also been reported as a predictive MRI criterion, and some studies have found this criterion as more reliable than the length of parenchymal T2W hyperintensity

Question 40

which is true about imaging features of ischaemic myelopathy? a) usually symmetrical b) usually involving the white matter mainly c) T1w iso to hypointense lesion d) no contrast enhancement in the first week

Answer 40

C is true a- usually asymmetrical b- usually mainly GM but a large number of dogs also have WM involvement d- variable enhancement in first week

Question 41

for ischaemic myelopathy, lesion length to vertebral length ratio of XX as a sensitivity of 100% in predicting a poor clinical outcome. A percentage cross-sectional area of the lesion of more than XX% has a sensitivity of 100% in predicting poor clinical outcome.

Answer 41

2.0 67% On average, the length of the spinal cord T2 hyperintensity observed on sagittal MR images in dogs with ischemic myelopathy is approximately 1.8 times the length of C6 for cervical or cervicothoracic lesions and 2.2 times the length of L2 for thoracolumbar and lumbosacral lesions.

Question 42

name 4 typical feature of discospondylitis

Answer 42

-Abnormal T1 hypointensity and T2 hypointensity of adjacent endplates and bone marrow; these lesions are hyperintense on T2W STIR images - Hyperintense disc on T2W images - Contrast enhancement of the intervertebral disc, vertebral endplates, and paravertebral soft tissues - Endplate erosion is usually present, but in early stages where endplate erosion is absent, the only change may be T2 and STIR hyperintensity of bone marrow adjacent to the end-plates - Spinal cord compression caused by extension of the infection to the epidural space - Vertebral subluxation on sagittal images

Question 43

name a typical feature of brucella discospondylitis

Answer 43

affected dogs are often young with multifocal lesions. Smooth, round, central endplate lytic changes, defined as “hole punch” lesions, can be seen on sagittal images and vertebral physitis or spondylitis without discitis may be seen; these can be identified as hyperintense vertebral lesions affecting the vertebral bodies on T2W or STIR images, with enhancement on postcontrast T1W images (best appreciated with fat saturation). Paravertebral inflammation with similar signal characteristics is also frequently seen

Question 44

which is not a feature of spinal epidural empyema? a) epidural mass effect b) T2w mixed signal, t1 hypointense c) T2* no signal voids d) rim like or diffuse enhancement

Answer 44

C- can get haemorrhage also, can get intramedullary signal change due to compression of the cord or vascular compromise

Question 45

name a viral cause of meningitis/ myelitis?

Answer 45

distemper fip

Question 46

name a fungal cause of meningitis/ myelitis?

Answer 46

crypto place to histo coccidiodes

Question 47

name a rickettsial cause of meningitis/ myelitis?

Answer 47

rickettsia Ehrlichia

Question 48

name a protozoal cause of meningitis/ myelitis?

Answer 48

toxo neospora

Question 49

name a parasitic cause of meningitis/ myelitis?

Answer 49

heartworm lungworm

Question 50

name an algal cause of meningitis/myelitis

Answer 50

prototheca

Question 51

name 5 groups of causes of menigiomyelitis

Answer 51

Noninfectious causes of canine meningomyelitis include granulomatous meningoencephalomyelitis, pyogranulomatous meningoencephalomyelitis, and steroid-responsive meningitis arteritis. Noninfectious causes of canine meningomyelitis include granulomatous meningoencephalomyelitis, pyogranulomatous meningoencephalomyelitis, and steroid-responsive meningitis arteritis.

Question 52

name 3 mri features of srma

Answer 52

T1W postcontrast enhancement of the meninges, synovium of the articular process joints, and paravertebral muscles with less commonly spinal cord parenchymal enhancement.273 Intradural hemorrhage causing cord compression

Question 53

what other diseases can be differentials for meningiomyelitis?

Answer 53

MRI changes of meningomyelitis are nonspecific, and other conditions (such as myelomalacia, ischemic myelopathy, or some neoplastic conditions such as histiocytic sarcoma or lymphosarcoma) can produce similar changes

Question 54

constrictive myelopathy in pugs, leading to meningeal fibrosis and subarachnoid diverticula are thought to be caused by...

Answer 54

caudal articular process malformation- book says thoracic spine Meningeal fibrosis causes irregular margination of the subarachnoid space best seen on T2W images, and enhancing meningeal thickening on T1W postcontrast images, located either dorsally or circumferentially. Focal T2W spinal cord parenchyma hyperintensity is commonly seen. Some studies also reported ventral extradural compression that is V-shaped on transverse images, corresponding histopathologically to areas of fibrosis and chondroid metaplasia

Question 55

name 3 causes of sryingomelia

Answer 55

abnormalities of the caudal fossa (Chiari-like malformations), but also other conditions, such as a quadrigeminal cistern cyst, tethered spinal cord, trauma, arachnoiditis, and neoplasia. Any condition that results in altered CSF flow in the caudal fossa of the skull or in the vertebral column can result in the development of a syrinx

Question 56

in chiari like malformation in ckcs, syrinx width of XX is most likely associated with clinical signs in 95% of dogs a) 0.32 b) 0.42 c) 0.64 d) 0.84

Answer 56

C although myelopathic signs develop as soon as the syrinx reaches 4 mm width. Larger syringes with involvement of the dorsal horns of the gray matter of the spinal cord and asymmetrical appearance on transverse images may be associated with persistent neuropathic pain