Flashcards in neuro imaging Deck (26)
Muguet-Chanoit AC, Olby NJ, Babb KM, Lim JH, Gallagher R, Niman Z, et al. The sensory field and repeatability of the cutaneous trunci muscle reflex of the dog. Vet Surg. 2011 Oct;40(7):781–5.
- normal dogs
- normal dogs
- C.T. reflex extends to L6 inmost dogs, and 50% around the hemicircumference
- rarely, normal elderly dogs can have it stop at cranial or mid lumbar
- contralateral muscle contraction is normally weaker, normal for it to get weaker as you move caudally
- moderate agreement between observers for caudal border
Muguet-Chanoit AC, Olby NJ, Lim JH, Gallagher R, Niman Z, Dillard S, et al. The Cutaneous Trunci Muscle Reflex: A Predictor of Recovery in Dogs with Acute Thoracolumbar Myelopathies Caused by Intervertebral Disc Extrusions. Vet Surg. 2012.
- paraplegic dogs with no deep pain before surgery
- dogs that had caudal movement of CT (n=19) by discharge were 9.6 x more likely to improve
- (but caudal movement of CT was not associated with long term success i.e. ambulatory long term)
- dogs that had caudal movement of CT had 0% chance of myelomalacia
- dogs that had cranial movement of CT (n=6) were 145x more likely to get myelomalacia
Witsberger TH, Levine JM, Fosgate GT, Slater MR, Kerwin SC, Russell KE, et al. Associations between cerebrospinal fluid biomarkers and long-term neurologic outcome in dogs with acute intervertebral disk herniation. J Am Vet Med Assoc. 2012 Mar 1;240(5):555–62.
- CSF taken at admission and tested for biomarkers
- For dogs who were plegic with no deep pain (MFS=0) or no superficial pain (MFS=1):
- if CSF CK > 38 U/L and CSF MBP (myelin basic protein) > 3 ng/ml, px for ambulation = 6%
- For any dog:
- if CSF CK 98%
- dogs with CK = 38 U/L had a 35 x chance of long-term ambulation
Srugo I, Aroch I, Christopher MM, Chai O, Goralnik L, Bdolah-Abram T, et al. Association of cerebrospinal fluid analysis findings with clinical signs and outcome in acute nonambulatory thoracolumbar disc disease in dogs. J Vet Intern Med. 2011 Jun;25(4):846–55.
- degree of CSF pleocytosis correlates with preoperative neurologic grade (high taps)
- Total nucleated cell count > 23.3 cells/ul is a negative px indicator
- in dogs with no deep pain sensation:
- macrophages > 13 % is a negative prognostic indicator
- macrophage:monocyte ratio > 0.64 is a negative prognostic indicator
Windsor RC, Vernau KM, Sturges BK, Kass PH, Vernau W. Lumbar cerebrospinal fluid in dogs with type I intervertebral disc herniation. J Vet Intern Med. 2008 Jan 1;22(4):954–60.
- incidence of pleocytosis was higher (51%) than previously reported in cervical and TL IVDD
- incidence of severe pleocytosis (51%) was also more than expected (TL IVDD only)
- dogs with IVDD > 7 days or acute-on-chronic signs more likely to have lymphocytic pleocytosis
- dogs with absent deep pain had higher TNCC’s
Jensen VF, Beck S, Christensen KA, Arnbjerg J. Quantification of the association between intervertebral disk calcification and disk herniation in Dachshunds. J Am Vet Med Assoc. 2008 Oct 1;233(7):1090–5.
- from intro: incidence of clinical IVDD in Dachshunds about 18%
- Dachshunds don’t get more calcified discs after 2 years, and in after 4 yrs they start to resorb them
- this study: # of calcified discs in entire spine correlated with risk of clinical disc herniation
- risk for dogs without any calcified discs 11%
- every disc increased OR by 1.42 times.
Da Costa RC, Parent JM, Dobson H. Incidence of and risk factors for seizures after myelography performed with iohexol in dogs: 503 cases (2002-2004). J Am Vet Med Assoc. 2011 May 15;238(10):1296–300.
- 3 % overall incidence of seizures (better than previous studies)
- prognostic factors:
- large dogs 35 X more likely
- cerebellomedullary injection (10%) 7.4 x more likely than lumbar injection (1.4%)
- dogs with cervical lesions (vs TL) 4.6 x more likely (remember dogs with Wobbler’s!)
- total volume injected (avoid volumes > 8 ml)
- Dobermans (20 %) and Rotties (43 %) – probably confounding since they are bigger & have cervical
- no surgery after tap (8.3 %) vs surgery after tap (0.84 %)
- duration of anesthesia? - not prognostic in this study
- acepromazine as premed? – not prognostic in this study
- other studies have shown multiple injections to be negative prognostic factor
Wolff CA, Holmes SP, Young BD, Chen AV, Kent M, Platt SR, et al. Magnetic resonance imaging for the differentiation of neoplastic, inflammatory, and cerebrovascular brain disease in dogs. J Vet Intern Med. 2012 May;26(3):589–97.
- radiologists are good at identifying neoplasia and inflammatory disease
- they are bad at identifying cerebrovascular disease
Sturges BK, Dickinson PJ, Bollen AW, Koblik PD, Kass PH, Kortz GD, et al. Magnetic resonance imaging and histological classification of intracranial meningiomas in 112 dogs. J Vet Intern Med. 2008 Jan 1;22(3):586–95.
- MRI cannot distinguish different grades or subtypes of meningioma
Bos AS, Brisson BA, Nykamp SG, Poma R, Foster RA. Accuracy, intermethod agreement, and inter-reviewer agreement for use of magnetic resonance imaging and myelography in small-breed dogs with naturally occurring first-time intervertebral disk extrusion. J Am Vet Med Assoc. 2012 Apr 15;240(8):969–77.
- MRI vs plain myelograms in chondrodystrophic IVDD – surgical gold standard
- MRI 100 % accurate for site and side
- myelography 91% accurate for site and 55% accurate for side
Newcomb B, Arble J, Rochat M, Pechman R, Payton M. Comparison of Computed Tomography and Myelography to a Reference Standard of Computed Tomographic Myelography for Evaluation of Dogs with Intervertebral Disc Disease. Vet Surg. 2011 Nov 4.
- from intro: studies in VetRadUltras have already compared CT to myelography using surgical findings as gold standard. They found:
- in chondrodystrophic dogs, they are about equal in finding the site
- also from intro: CT plain is not as good without mineralized disc material or if there is neoplasia
- this study: CT vs myelography – CT myelogram was gold standard
- CT is more sensitive than myelography for localizing disc extrusions
- if the radiologist is confident, he/she is more likely to be more sensitive
Schroeder R, Pelsue DH, Park RD, Gasso D, Bruecker KA. Contrast-Enhanced CT for Localizing Compressive Thoracolumbar Intervertebral Disc Extrusion. J Am Anim Hosp Assoc. 2011 Apr;47(3):203–9.
- CT with IV contrast vs CT myelography (surgery is gold standard)
- conclusion: CT w/IV contrast was just as sensitive as CT/myelogram in these mostly chondrodystropic
Bergknut N, Grinwis G, Pickee E, Auriemma E, Lagerstedt A-S, Hagman R, et al. Reliability of macroscopic grading of intervertebral disk degeneration in dogs by use of the Thompson system and comparison with low-field magnetic resonance imaging findings. Am J Vet Res. 2011 Jul;72(7):899–904.
Bergknut N, Auriemma E, Wijsman S, Voorhout G, Hagman R, Lagerstedt A-S, et al. Evaluation of intervertebral disk degeneration in chondrodystrophic and nonchondrodystrophic dogs by use of Pfirrmann grading of images obtained with low-field magnetic resonance imaging. Am J Vet Res. 2011 Jul;72(7):893–8.
- validating human-based Pfirrmann scale for evaluating disc degeneration.
- 1st paper showed it correlated with gross appearance (Thompson grade)
- 2nd paper showed it correlated with age and chondrodystrophic breeds
- Pfirrmann grades:
1: homogenous and white, clear distinction, normal space size
2: nonhomogenous, clear distinction, normal space size
3: nonhomogenous and grey, indistinct, normal size
4: nonhomogenous and grey to black, no distinction, normal to decreased size
5: nonhomogenous, black, no distinction, collapsed disc space
Okada M, Kitagawa M, Ito D, Itou T, Kanayama K, Sakai T. Magnetic resonance imaging features and clinical signs associated with presumptive and confirmed progressive myelomalacia in dogs: 12 cases (1997-2008). J Am Vet Med Assoc. 2010 Nov 15;237(10):1160–5.
- 12 dogs with suspected or confirmed progressive myelomalacia (80% mini Dachshunds)
- MRI features of myelomalacia (some before clinical diagnosis): extensive T2W hyperintensity > 6 x L2
- CSF features: xanthochromia, hemorrhagic
de Risio L, Adams V, Dennis R, McConnell FJ. Association of clinical and magnetic resonance imaging findings with outcome in dogs with presumptive acute noncompressive nucleus pulposus extrusion: 42 cases (2000-2007). J Am Vet Med Assoc. 2009 Feb 15;234(4):495–504.
- 42 dogs with ANNPE
- overall success rate 67% (overall rate of poor outcome = 1/3rd)
- best prognostic indicator = percent of T2 hyperintensity on a transverse image at maximum point
- > or = 90 % hyperintensity means 92 % chance of a poor outcome
de Risio L, Adams V, Dennis R, McConnell FJ, Platt SR. Association of clinical and magnetic resonance imaging findings with outcome in dogs suspected to have ischemic myelopathy: 50 cases (2000-2006). J Am Vet Med Assoc. 2008 Jul 1;233(1):129–35.
- 50 dogs with presumptive FCE – 84% overall successful outcomes
- 78 % of dogs had a lesion on MRI
- all the dogs without an MRI lesion had a successful outcome
- prognostic for outcome:
- neurologic score at presentation (conflicts with other studies, authors say other studies were lame)
- T2W length ratio: if 2.0 dog has 50% chance
- cross-sectional area: if 67% dog has 65% chance
- NOT prognostic in this study:
- lesion localization (not statistically, but all dogs with poor outcome had intumescence lesions)
- CSF findings
Levine JM, Fosgate GT, Chen AV, Rushing R, Nghiem PP, Platt SR, et al. Magnetic resonance imaging in dogs with neurologic impairment due to acute thoracic and lumbar intervertebral disk herniation. J Vet Intern Med. 2009 Jan 1;23(6):1220–6.
- “Each unit of T2W length ratio was associated with a 1.9 times lower odds of long-term ambulation”
- dog with T2W length ratio > 1.24 had prognosis of 62 % for ambulation
Naudé SH, Lambrechts NE, Wagner WM, Thompson PN. Association of preoperative magnetic resonance imaging findings with surgical features in Dachshunds with thoracolumbar intervertebral disk extrusion. J Am Vet Med Assoc. 2008 Mar 1;232(5):702–8.
- T2 weighted images are the most accurate for lesion location and size/length
de Decker S, van Soens I, Duchateau L, Gielen IMVL, van Bree HJJ, Binst DHAR, et al. Transcranial magnetic stimulation in Doberman Pinschers with clinically relevant and clinically irrelevant spinal cord compression on magnetic resonance imaging. J Am Vet Med Assoc. 2011 Jan 1;238(1):81–8.
- transcranial magnetic motor evoked potentials (PMMEPs), transcranial magnetic stimulation (TMS)
- might be used to differentiate clinically important from not important compression in Dobie necks
- latency was more helpful than amplitude
Decker S, Gielen IMVL, Duchateau L, Corzo-Menéndez N, van Bree HJJ, Kromhout K, et al. Intraobserver, interobserver, and intermethod agreement for results of myelography, computed tomography-myelography, and low-field magnetic resonance imaging in dogs with disk-associated wobbler syndrome. J Am Vet Med Assoc. 2011 Jun 15;238(12):1601–8.
- myelogram vs CT myelogram vs MRI (no gold standard, just compared with eachother)
- modalities are better at seeing different things and should be considered “complimentary”
- the most agreement was in determining site of worst compression and direction of compression
- the least agreement was in determining foraminal stenosis and state of articular facets
de Decker S, Gielen IMVL, Duchateau L, Lang J, Dennis R, Corzo-Menéndez N, et al. Intraobserver and interobserver agreement for results of low-field magnetic resonance imaging in dogs with and without clinical signs of disk-associated wobbler syndrome. J Am Vet Med Assoc. 2011 Jan 1;238(1):74–80.
- MRI leads to 17% false positives and 10% false negatives when compared to clinical signs
- ISI (intraspinal signal intensity) was the most reliable predictor of clinical affectedness
de Decker S, Gielen IMVL, Duchateau L, Polis I, van Bree HJJ, van Ham LML. Agreement and repeatability of linear vertebral body and canal measurements using computed tomography (CT) and low field magnetic resonance imaging (MRI). Vet Surg. 2010 Jan;39(1):28–34.
all vertebral measurements on CT and MR are pretty reliable, except for vertebral body length on CT
de Decker S, Gielen IMVL, Duchateau L, van Soens I, Bavegems V, Bosmans T, et al. Low-field magnetic resonance imaging findings of the caudal portion of the cervical region in clinically normal Doberman Pinschers and Foxhounds. Am J Vet Res. 2010 Apr 1;71(4):428–34.
- normal dobies and foxhounds have severe caudal cervical (C5-6-7) lesions on MRI
- 76 % had disc degeneration (50% had degeneration so bad the disc looked black)
- 30 % had ventral spinal cord compression
- 8 % had dorsal spinal cord compression
- 5% had spinal cord hyperintensity!
- these signs seem to get worse as dogs age
- Dobies only: 35 % had vertebral body abnormalities – this was not associated with age
Konar M, Lang J, Flühmann G, Forterre F. Ventral intraspinal cysts associated with the intervertebral disc: magnetic resonance imaging observations in seven dogs. Vet Surg. 2008 Jan 1;37(1):94–101.
authors propose name “canine discal cysts”
- other types of cysts: arachnoid, synovial (“juxtafacet”), meningeal, spinal (epi)dermoid cysts
- these usually occurred in the caudal cervical spine
Hettlich BF, Fosgate GT, Levine JM, Young BD, Kerwin SC, Walker M, et al. Accuracy of conventional radiography and computed tomography in predicting implant position in relation to the vertebral canal in dogs. Vet Surg. 2010 Aug;39(6):680–7.
- radiographs are only 50% sensitive for detecting pin penetration into vertebral canals
- CT was 93 % sensitive