Quick and complete evaluation of animals that are critically ill is mandatory. Radiographs and ultrasound are the current mainstays of emergency imaging; however, advanced imaging studies such as computed tomography and magnetic resonance imaging (MRI) are being used with increasing frequency. MRI technology provides for exceptional imaging of anatomic detail, especially of soft tissues throughout the body. This chapter focuses on the use of MRI in emergency situations. For animals, the most experience with MRI has been gained in imaging the central nervous system (CNS). Emergency MRI for non-CNS disease is generally related to acute hemorrhagic disorders. Such hemorrhagic studies above the diaphragm of an emergency nature are generally of the nasal cavity. Emergency MRI studies below the diaphragm generally involve acute abdominal fluid accumulation. Portosystemic shunts and the associated hepatic encephalopathy may be seen on an emergency basis and the shunts can be diagnosed via MRI angiography.

OBJECTIVE:To determine the influence of low-intensity pulsed ultrasound (LIPUS) on radiographic healing and limb function after uncomplicated, stable osteotomies in dogs.STUDY DESIGN:In vivo, prospective, randomized, double-blinded, placebo-control study.SAMPLE POPULATION:Fifty client-owned dogs.METHODS:Fifty client-owned dogs with naturally occurring unilateral cranial cruciate ligament rupture were enrolled prior to tibial plateau leveling osteotomy. Dogs were assigned to an active (LIPUS) treatment group or a placebo control (SHAM) treatment group via block randomization on the basis of age, weight, and affected limb. Dogs in the LIPUS treatment group underwent LIPUS treatments for 20 minutes daily: 1.5-MHZ ultrasound wave pulsed at 1 kHZ with a 20% duty cycle at an intensity of 30 mW/cm2 for the duration of the study (12 weeks). Radiographic evaluation was performed at 4, 8, 10, and 12 weeks postoperatively to evaluate bone healing. Limb function was assessed with temporal-spatial gait analysis preoperatively and at 4, 8, and 12 weeks postoperatively by using a pressure-sensitive walkway system.RESULTS:Both groups had significant improvement in radiographic score and limb use over time. However, there was no significant difference in radiographic bone healing, or limb use as measured by objective gait analysis detected between the LIPUS treatment group and SHAM treatment group at any point in the study.CONCLUSION:LIPUS treatment did not improve healing in this stable osteotomy model.CLINICAL SIGNIFICANCE:This study does not provide evidence to support the clinical application of LIPUS to stimulate the healing of stable, uncomplicated osteotomies to accelerate bone healing.

CASE DESCRIPTIONA 9-year-old spayed female Rottweiler with hind limb ataxia was examined because of anorexia and an acute onset of hind limb paresis.CLINICAL FINDINGSNeurologic evaluation revealed hind limb ataxia and symmetric paraparesis with bilaterally abnormal hind limb postural reactions including hopping, hemiwalking, hemistanding, and delayed proprioception, which were suggestive of a lesion somewhere in the T3-L3 segment of the spinal cord. Thoracolumbar radiography revealed an abnormal radiopacity suggestive of a mass at T11. Two 3.5-cm-long osseous core biopsy specimens of the mass were obtained by MRI guidance. Histologic appearance of the specimens was consistent with osteosarcoma.TREATMENT AND OUTCOMEThe owners of the dog declined further treatment owing to a poor prognosis. The dog was euthanized within 12 months after diagnosis because of a declining quality of life.CLINICAL RELEVANCEThe acquisition of biopsy specimens by MRI guidance is an emerging technique in veterinary medicine. As evidenced by the dog of this report, MRIguided biopsy can be used to safely obtain diagnostic biopsy specimens from tissues at anatomic locations that are difficult to access. This technique can potentially be used to facilitate early diagnosis and treatment of disease, which could improve patient outcome. The MRI guidance technique described may also be useful for local administration of chemotherapeutics or radiofrequency ablation or cryoablation of various neoplasms of the vertebral column.

MRI has the unique ability to detect abnormal fluid content, and is therefore unparalleled in its role of detection, diagnosis, prognosis, treatment planning and follow-up evaluation of musculoskeletal disease. MRI in companion animals should be considered in the following circumstances: a definitive diagnosis cannot be made on radiographs; a patient is nonresponsive to medical or surgical therapy; prognostic information is desired; assessing surgical margins and traumatic and/or infectious joint and bone disease; ruling out subtle developmental or early aggressive bone lesions. The MRI features of common disorders affecting the shoulder, elbow, stifle, carpal, and tarsal joints are included in this chapter.

OBJECTIVETo evaluate the effects of a new microfracture and ligament splitting procedure on ligament healing and to examine the usefulness of magnetic resonance (MR) imaging for monitoring ligament healing over time using a collagenase model of hind limb proximal suspensory desmitis.STUDY DESIGNExperimental in vivo study.ANIMALSHealthy adult horses (n=6).METHODSHorses were free of lameness with normal hind limb proximal suspensory ligaments (PSL). The origin of both hind limb PSL was injected with collagenase and underwent MR imaging 2 weeks later, followed by the microfracture and ligament splitting procedure on 1 limb, with the opposite limb serving as the sham-operated control. Serial lameness and MR examinations were performed. Horses were euthanatized 210 days after surgery, the PSL harvested, and histology, biochemistry, and gene expression performed on both PSL.RESULTSCollagenase lesions viewed on MR images appeared similar to those seen clinically. Serial MR images demonstrated resolution of abnormal signal intensity and tissue formation in the microfracture sites within the third metatarsal bone. Treated limbs had histologic evidence of connective tissue appearing to originate from the small perforations and blending into the ligament but no statistical differences were identified. Gene expression for cartilage oligomeric matrix protein and decorin were significantly increased in treated compared to control limbs.CONCLUSIONThe microfracture and ligament splitting procedure did incite a tissue response but further clinical investigation is necessary to determine if this tissue remodeling at the bone-ligament interface translates to improved clinical outcome. MR imaging may be useful to follow healing in horses with hind limb proximal suspensory desmitis.

Chapter 16 Advances in Imaging for Intervertebral Disc Disease Patrick R. Gavin, Patrick R. GavinSearch for more papers by this authorJonathan M. Levine, Jonathan M. LevineSearch for more papers by this author Patrick R. Gavin, Patrick R. GavinSearch for more papers by this authorJonathan M. Levine, Jonathan M. LevineSearch for more papers by this author Book Editor(s):James M. Fingeroth, James M. Fingeroth Orchard Park Veterinary Medical Center, USASearch for more papers by this authorWilliam B. Thomas, William B. Thomas College of Veterinary Medicine, University of Tennessee, USASearch for more papers by this author First published: 12 December 2014 https://doi.org/10.1002/9781118940372.ch16 AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onEmailFacebookTwitterLinkedInRedditWechat Summary There are various imaging modalities employed for dogs and cats with suspected intervertebral disc herniation (IVDH). Conventional radiography became widely available in the 1950s and 1960s in the veterinary profession. Accurate positioning requires heavy sedation or general anesthesia. Myelography requires general anesthesia and a degree of skill in the placement of the material within the subarachnoid space. Computed tomography (CT) offered improved visualization of tissues due to the ability to manipulate the contrast windows and levels. The combination of myelography and CT yields an improved diagnostic capability. Magnetic resonance imaging (MRI) became more available in the beginning of the twenty-first century. It is widely accepted that MRI has improved visualization of spinal disease. There has been a major shift in the imaging of intervertebral disc disease with ever-increasing improvement in the diagnosis, which is leading to improved therapies and clinical outcomes. References Hoerlein BF. Intervertebral disc protrusions in the dog. III. Radiological diagnosis. Am J Vet Res. 1953 Apr; 14(51): 275–86. CASPubMedWeb of Science®Google Scholar Lee R. Interpretation of radiographs: inter-vertebral disc lesions in the dog. J Small Anim Pract. 1973 Feb; 14(2): 111–2. 10.1111/j.1748-5827.1973.tb06901.x CASPubMedWeb of Science®Google Scholar Lewis RE. Roentgen signs of the spine. Vet Clin North Am. 1974 Nov; 4(4): 647–61. 10.1016/S0091-0279(74)50078-4 CASPubMedGoogle Scholar Bennett D, Carmichael S, Griffiths IR. Discospondylitis in the dog. J Small Anim Pract. 1981 Aug; 22(8): 539–47. 10.1111/j.1748-5827.1981.tb00640.x CASPubMedWeb of Science®Google Scholar Kinns J, Mai W, Seiler G, Zwingenberger A, Johnson V, Caceres A, et al. Radiographic sensitivity and negative predictive value for acute canine spinal trauma. Vet Radiol Ultrasound. 2006 Oct–Nov; 47(6): 563–70. 10.1111/j.1740-8261.2006.00186.x CASPubMedWeb of Science®Google Scholar Carrera I, Sullivan M, McConnell F, Goncalves R. Magnetic resonance imaging features of discospondylitis in dogs. Vet Radiol Ultrasound. 2011 Mar–Apr; 52(2): 125–31. 10.1111/j.1740-8261.2010.01756.x PubMedWeb of Science®Google Scholar Somerville ME, Anderson SM, Gill PJ, Kantrowitz BJ, Stowater JL. Accuracy of localization of cervical intervertebral disk extrusion or protrusion using survey radiography in dogs. J Am Anim Hosp Assoc. 2001 Nov–Dec; 37(6): 563–72. 10.5326/15473317-37-6-563 CASPubMedWeb of Science®Google Scholar Lamb CR, Nicholls A, Targett M, Mannion P. Accuracy of survey radiographic diagnosis of intervertebral disc protrusion in dogs. Vet Radiol Ultrasound. 2002 May–Jun; 43(3): 222–8. 10.1111/j.1740-8261.2002.tb00994.x CASPubMedWeb of Science®Google Scholar Burk R. Problems in the radiographic interpretation of intervertebral disc disease in the dog. Probl Vet Med. 1988; 1(3): 381–401. Google Scholar Morgan JP, Suter PF, Holliday TA. Myelography with water-soluble contrast medium. Radiographic interpretation of disc herniation in dogs. Acta Radiol Suppl. 1972; 319: 217–30. CASPubMedGoogle Scholar Kahanovitz N, Arnoczky SP, Sissons HA, Steiner GC, Schwarez P. The effect of discography on the canine intervertebral disc. Spine (Phila Pa 1976). 1986 Jan–Feb; 11(1): 26–7. 10.1097/00007632-198601000-00007 CASPubMedWeb of Science®Google Scholar Bos AS, Brisson BA, Holmberg DL, Nykamp SG. Use of the ventrodorsal myelographic view to predict lateralization of extruded disk material in small-breed dogs with thoracolumbar intervertebral disk extrusion: 104 cases (2004–2005). J Am Vet Med Assoc. 2007 Jun 15; 230(12): 1860–5. 10.2460/javma.230.12.1860 PubMedGoogle Scholar Gibbons SE, Macias C, De Stefani A, Pinchbeck GL, McKee WM. The value of oblique versus ventrodorsal myelographic views for lesion lateralisation in canine thoracolumbar disc disease. J Small Anim Pract. 2006 Nov; 47(11): 658–62. 10.1111/j.1748-5827.2006.00067.x CASPubMedWeb of Science®Google Scholar Schulz KS, Walker M, Moon M, Waldron D, Slater M, McDonald DE. Correlation of clinical, radiographic, and surgical localization of intervertebral disc extrusion in small-breed dogs: a prospective study of 50 cases. Vet Surg. 1998 Mar–Apr; 27(2): 105–11. 10.1111/j.1532-950X.1998.tb00105.x CASPubMedWeb of Science®Google Scholar Tanaka H, Nakayama M, Takase K. Usefulness of myelography with multiple views in diagnosis of circumferential location of disc material in dogs with thoracolumbar intervertebral disc herniation. J Vet Med Sci. 2004 Jul; 66(7): 827–33. 10.1292/jvms.66.827 PubMedWeb of Science®Google Scholar Lexmaulova L, Zatloukal J, Proks P, Dvorak M, Srnec R, Rauser P, et al. Incidence of seizures associated with iopamidol or iomeprol myelography in dogs with intervertebral disk disease: 161 cases (2000–2002). J Vet Emerg Crit Care (San Antonio). 2009 Dec; 19(6): 611–6. 10.1111/j.1476-4431.2009.00479.x CASPubMedWeb of Science®Google Scholar Lim C, Kweon OK, Choi MC, Choi J, Yoon J. Computed tomographic characteristics of acute thoracolumbar intervertebral disc disease in dogs. J Vet Sci. 2010 Mar; 11(1): 73–9. 10.4142/jvs.2010.11.1.73 PubMedWeb of Science®Google Scholar Hecht S, Thomas WB, Marioni-Henry K, Echandi RL, Matthews AR, Adams WH. Myelography vs. computed tomography in the evaluation of acute thoracolumbar intervertebral disk extrusion in chondrodystrophic dogs. Vet Radiol Ultrasound. 2009 Jul–Aug; 50(4): 353–9. 10.1111/j.1740-8261.2009.01549.x CASPubMedWeb of Science®Google Scholar King JB, Jones JC, Rossmeisl JH, Harper TA, Lanz OI, Werre SR. Effect of multi-planar CT image reformatting on surgeon diagnostic performance for localizing thoracolumbar disc extrusions in dogs. J Vet Sci. 2009; 10(3): 225–32. 10.4142/jvs.2009.10.3.225 PubMedWeb of Science®Google Scholar Olby NJ, Munana KR, Sharp NJ, Thrall DE. The computed tomographic appearance of acute thoracolumbar intervertebral disc herniations in dogs. Vet Radiol Ultrasound. 2000 Sep–Oct; 41(5): 396–402. 10.1111/j.1740-8261.2000.tb01860.x CASPubMedWeb of Science®Google Scholar Kuroki K, Vitale CL, Essman SC, Pithua P, Coates JR. Computed tomographic and histological findings of Hansen type I intervertebral disc herniation in dogs. Vet Comp Orthop Traumatol. 2013; 26(5): 379–84. 10.3415/VCOT-12-08-0105 CASPubMedWeb of Science®Google Scholar Kent M, Holmes S, Cohen E, Sakals S, Roach W, Platt S, et al. Imaging diagnosis-CT myelography in a dog with intramedullary intervertebral disc herniation. Vet Radiol Ultrasound. 2011 Mar–Apr; 52(2): 185–7. 10.1111/j.1740-8261.2010.01755.x PubMedWeb of Science®Google Scholar Hara Y, Tagawa M, Ejima H, Orima H, Fujita M. Usefulness of computed tomography after myelography for surgery on dogs with cervical intervertebral disc protrusion. J Vet Med Sci. 1994 Aug; 56(4): 791–4. 10.1292/jvms.56.791 CASPubMedWeb of Science®Google Scholar Jones JC, Inzana KD, Rossmeisl JH, Bergman RL, Wells T, Butler K. CT myelography of the thoraco-lumbar spine in 8 dogs with degenerative myelopathy. J Vet Sci. 2005 Dec; 6(4): 341–8. PubMedGoogle Scholar Shimizu J, Yamada K, Mochida K, Kako T, Muroya N, Teratani Y, et al. Comparison of the diagnosis of intervertebral disc herniation in dogs by CT before and after contrast enhancement of the subarachnoid space. Vet Rec. 2009 Aug 15; 165(7): 200–2. 10.1136/vr.165.7.200 CASPubMedWeb of Science®Google Scholar 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 May–Jun; 47(3): 203–9. 10.5326/JAAHA-MS-5550 PubMedWeb of Science®Google Scholar Adamiak Z, Pomianowski A, Zhalniarovich Y, Kwiatkowska M, Jaskolska M, Bochenska A. A comparison of magnetic resonance imaging sequences in evaluating pathological changes in the canine spinal cord. Pol J Vet Sci. 2011; 14(3): 481–4. 10.2478/v10181-011-0072-1 CASPubMedWeb of Science®Google Scholar Amort KH, Ondreka N, Rudorf H, Stock KF, Distl O, Tellhelm B, et al. MR-imaging of lumbosacral intervertebral disc degeneration in clinically sound German shepherd dogs compared to other breeds. Vet Radiol Ultrasound. 2012 May–Jun; 53(3): 289–95. 10.1111/j.1740-8261.2011.01903.x PubMedWeb of Science®Google Scholar Beltran E, Dennis R, Doyle V, de Stefani A, Holloway A, de Risio L. Clinical and magnetic resonance imaging features of canine compressive cervical myelopathy with suspected hydrated nucleus pulposus extrusion. J Small Anim Pract. 2012 Feb; 53(2): 101–7. 10.1111/j.1748-5827.2011.01166.x CASPubMedWeb of Science®Google Scholar Bergknut N, Grinwis G, Pickee E, Auriemma E, Lagerstedt AS, 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; 72(7): 899–904. 10.2460/ajvr.72.7.899 PubMedWeb of Science®Google Scholar Besalti O, Pekcan Z, Sirin YS, Erbas G. Magnetic resonance imaging findings in dogs with thoracolumbar intervertebral disk disease: 69 cases (1997–2005). J Am Vet Med Assoc. 2006 Mar 15; 228(6): 902–8. 10.2460/javma.228.6.902 PubMedWeb of Science®Google Scholar Chambers JN, Selcer BA, Sullivan SA, Coates JR. Diagnosis of lateralized lumbosacral disk herniation with magnetic resonance imaging. J Am Anim Hosp Assoc. 1997 Jul–Aug; 33(4): 296–9. 10.5326/15473317-33-4-296 CASPubMedWeb of Science®Google Scholar Chang Y, Dennis R, Platt SR, Penderis J. Magnetic resonance imaging of traumatic intervertebral disc extension in dogs. Vet Rec. 2007; 160(23): 795–9. 10.1136/vr.160.23.795 CASPubMedWeb of Science®Google Scholar 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; 39(1): 28–34. 10.1111/j.1532-950X.2009.00559.x CASPubMedWeb of Science®Google Scholar de Haan JJ, Shelton SB, Ackerman N. Magnetic resonance imaging in the diagnosis of degenerative lumbosacral stenosis in four dogs. Vet Surg. 1993 Jan–Feb; 22(1): 1–4. 10.1111/j.1532-950X.1993.tb00359.x CASPubMedWeb of Science®Google Scholar De Risio L, Platt SR. Fibrocartilaginous embolic myelopathy in small animals. Vet Clin North Am Small Anim Pract. 2010 Sep; 40(5): 859–69. 10.1016/j.cvsm.2010.05.003 PubMedWeb of Science®Google Scholar Freeman AC, Platt SR, Kent M, Howerth E, Holmes SP. Magnetic resonance imaging enhancement of intervertebral disc disease in 30 dogs following chemical fat saturation. J Small Anim Pract. 2012 Feb; 53(2): 120–5. 10.1111/j.1748-5827.2011.01174.x CASPubMedWeb of Science®Google Scholar Freeman P. Sacrococcygeal intervertebral disc extrusion in a dachshund. Vet Rec. 2010; 167(16): 618–9. 10.1136/vr.c4829 CASPubMedWeb of Science®Google Scholar Forterre F, Gorgas D, Dickomeit M, Jaggy A, Lang J, Spreng D. Incidence of spinal compressive lesions in chondrodystrophic dogs with abnormal recovery after hemilaminectomy for treatment of thoracolumbar disc disease: a prospective magnetic resonance imaging study. Vet Surg. 2010 Feb; 39(2): 165–72. 10.1111/j.1532-950X.2009.00633.x CASPubMedWeb of Science®Google Scholar Gambino J. What is your diagnosis? J Am Vet Med Assoc. 2010; 236(11): 1177–8. 10.2460/javma.236.11.1177 PubMedWeb of Science®Google Scholar Gendron K, Doherr MG, Gavin PR, Lang J. Magnetic resonance imaging characterization of vertebral endplate changes in the dog. Vet Radiol Ultrasound. 2012; 53(1): 50–6. 10.1111/j.1740-8261.2011.01861.x PubMedWeb of Science®Google Scholar Gonzalo-Orden JM, Altonaga JR, Orden MA, Gonzalo JM. Magnetic resonance, computed tomographic and radiologic findings in a dog with discospondylitis. Vet Radiol Ultrasound. 2000 Mar–Apr; 41(2): 142–4. 10.1111/j.1740-8261.2000.tb01467.x CASPubMedWeb of Science®Google Scholar Grunenfelder FI, Weishaupt D, Green R, Steffen F. Magnetic resonance imaging findings in spinal cord infarction in three small breed dogs. Vet Radiol Ultrasound. 2005 Mar–Apr; 46(2): 91–6. 10.1111/j.1740-8261.2005.00019.x PubMedWeb of Science®Google Scholar Ito D, Matsunaga S, Jeffery ND, Sasaki N, Nishimura R, Mochizuki M, et al. Prognostic value of magnetic resonance imaging in dogs with paraplegia caused by thoracolumbar intervertebral disk extrusion: 77 cases (2000–2003). J Am Vet Med Assoc. 2005 Nov 1; 227(9): 1454–60. 10.2460/javma.2005.227.1454 PubMedWeb of Science®Google Scholar Konar M, Lang J, Fluhmann G, Forterre F. Ventral intraspinal cysts associated with the intervertebral disc: magnetic resonance imaging observations in seven dogs. Vet Surg. 2008 Jan; 37(1): 94–101. 10.1111/j.1532-950X.2007.00353.x CASPubMedWeb of Science®Google Scholar Kraft SL, Mussman JM, Smith T, Biller DS, Hoskinson JJ. Magnetic resonance imaging of presumptive lumbosacral discospondylitis in a dog. Vet Radiol Ultrasound. 1998 Jan–Feb; 39(1): 9–13. 10.1111/j.1740-8261.1998.tb00318.x CASPubMedWeb of Science®Google Scholar Lawson CM, Reichle JK, McKlveen T, Smith MO. Imaging findings in dogs with caudal intervertebral disc herniation. Vet Radiol Ultrasound. 2011 Sep–Oct; 52(5): 487–91. 10.1111/j.1740-8261.2011.01835.x PubMedWeb of Science®Google Scholar Lowrie M, Carrera I, Trevail T, Wessmann A. What is your diagnosis? Hansen type 1 intervertebral disk disease. J Am Vet Med Assoc. 2009 Oct 1; 235(7): 823–4. 10.2460/javma.235.7.823 PubMedWeb of Science®Google Scholar Mateo I, Lorenzo V, Foradada L, Munoz A. Clinical, pathologic, and magnetic resonance imaging characteristics of canine disc extrusion accompanied by epidural hemorrhage or inflammation. Vet Radiol Ultrasound. 2011 Jan–Feb; 52(1): 17–24. 10.1111/j.1740-8261.2010.01746.x PubMedWeb of Science®Google Scholar Nakamoto Y, Ozawa T, Katakabe K, Nishiya K, Yasuda N, Mashita T, et al. Fibrocartilaginous embolism of the spinal cord diagnosed by characteristic clinical findings and magnetic resonance imaging in 26 dogs. J Vet Med Sci. 2009 Feb; 71(2): 171–6. 10.1292/jvms.71.171 PubMedWeb of Science®Google Scholar Penning VA, Benigni L, Steeves E, Cappello R. Imaging diagnosis—degenerative intraspinal cyst associated with an intervertebral disc. Vet Radiol Ultrasound. 2007 Sep–Oct; 48(5): 424–7. 10.1111/j.1740-8261.2007.00272.x PubMedWeb of Science®Google Scholar Platt SR, McConnell JF, Bestbier M. Magnetic resonance imaging characteristics of ascending hemorrhagic myelomalacia in a dog. Vet Radiol Ultrasound. 2006 Jan–Feb; 47(1): 78–82. 10.1111/j.1740-8261.2005.00109.x PubMedWeb of Science®Google Scholar Seiler G, Hani H, Scheidegger J, Busato A, Lang J. Staging of lumbar intervertebral disc degeneration in nonchondrodystrophic dogs using low-field magnetic resonance imaging. Vet Radiol Ultrasound. 2003 Mar–Apr; 44(2): 179–84. 10.1111/j.1740-8261.2003.tb01268.x CASPubMedWeb of Science®Google Scholar An HS, Nguyen C, Haughton VM, Ho KC, Hasegawa T. Gadolinium-enhancement characteristics of magnetic resonance imaging in distinguishing herniated intervertebral disc versus scar in dogs. Spine (Phila Pa 1976). 1994 Sep 15; 19(18): 2089–94; discussion 95. 10.1097/00007632-199409150-00015 CASPubMedWeb of Science®Google Scholar Cooper JJ, Young BD, Griffin JFt, Fosgate GT, Levine JM. Comparison between noncontrast computed tomography and magnetic resonance imaging for detection and characterization of thoracolumbar myelopathy caused by intervertebral disk herniation in dogs. Vet Radiol Ultrasound. 2013 Oct 9; 55: 182–90. 10.1111/vru.12114 PubMedWeb of Science®Google Scholar Freer SR, Scrivani PV. Postoperative susceptibility artifact during magnetic resonance imaging of the vertebral column in two dogs and a cat. Vet Radiol Ultrasound. 2008 Jan–Feb; 49(1): 30–4. 10.1111/j.1740-8261.2007.00313.x PubMedWeb of Science®Google Scholar Guillem Gallach R, Suran J, Caceres AV, Reetz JA, Brown DC, Mai W. Reliability of T2-weighted sagittal magnetic resonance images for determining the location of compressive disk herniation in dogs. Vet Radiol Ultrasound. 2011 Sep–Oct; 52(5): 479–86. 10.1111/j.1740-8261.2011.01833.x CASPubMedWeb of Science®Google Scholar 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 Nov–Dec; 23(6): 1220–6. 10.1111/j.1939-1676.2009.0393.x CASPubMedWeb of Science®Google Scholar Yamada K, Nakagawa M, Kato T, Shigeno S, Hirose T, Miyahara K, et al. Application of short-time magnetic resonance examination for intervertebral disc diseases in dogs. J Vet Med Sci. 2001 Jan; 63(1): 51–4. 10.1292/jvms.63.51 CASPubMedWeb of Science®Google Scholar Naude 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. 10.2460/javma.232.5.702 PubMedWeb of Science®Google Scholar Suran JN, Durham A, Mai W, Seiler GS. Contrast enhancement of extradural compressive material on magnetic resonance imaging. Vet Radiol Ultrasound. 2011 Jan–Feb; 52(1): 10–6. 10.1111/j.1740-8261.2010.01734.x PubMedWeb of Science®Google Scholar Mankin JM, Hecht S, Thomas WB. Agreement between T2 and haste sequences in the evaluation of thoracolumbar intervertebral disc disease in dogs. Vet Radiol Ultrasound. 2012 Mar–Apr; 53(2): 162–6. 10.1111/j.1740-8261.2011.01894.x PubMedWeb of Science®Google Scholar Tidwell AS, Specht A, Blaeser L, Kent M. Magnetic resonance imaging features of extradural hematomas associated with intervertebral disc herniation in a dog. Vet Radiol Ultrasound. 2002 Jul–Aug; 43(4): 319–24. 10.1111/j.1740-8261.2002.tb01011.x PubMedWeb of Science®Google Scholar Robertson I, Thrall DE. Imaging dogs with suspected disc herniation: pros and cons of myelography, computed tomography, and magnetic resonance. Vet Radiol Ultrasound. 2011 Mar–Apr; 52(1 Suppl 1): S81–4. 10.1111/j.1740-8261.2010.01788.x PubMedWeb of Science®Google Scholar Advances in Intervertebral Disc Disease in Dogs and Cats ReferencesRelatedInformation

The effect of orthohydrogen-parahydrogen concentration on the performance of a proton exchange membrane fuel cell is calculated and experimentally investigated. Gibbs free energy and reversible cell potential calculations predict that parahydrogen at room temperature produces a voltage 20 mV/cell higher than normal hydrogen and a 1.6% increase in efficiency over normal hydrogen. Experimental data based on a 1 kW proton exchange membrane fuel cell rapidly switched between normal and parahydrogen did not show a statistically significant difference in performance. Variations due to stack humidity and anode purging are found to dominate fuel cell output. The experimental results confirm that, as anticipated, parahydrogen concentration has a negligible impact on fuel cell performance for the majority of practical applications. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Low-field magnetic resonance imaging (MRI) is commonly used to evaluate dogs with suspected cranial cruciate ligament injury; however, effects of stifle positioning and scan plane on visualization of the ligament are incompletely understood. Six stifle joints (one pilot, five test) were collected from dogs that were scheduled for euthanasia due to reasons unrelated to the stifle joint. Each stifle joint was scanned in three angles of flexion (90°, 135°, 145°) and eight scan planes (three dorsal, three axial, two sagittal), using the same low-field MRI scanner and T2-weighted fast spin echo scan protocol. Two experienced observers who were unaware of scan technique independently scored visualization of the cranial cruciate ligament in each scan using a scale of 0-3. Visualization score rank sums were higher when the stifle was flexed at 90° compared to 145°, regardless of the scan plane. Visualization scores for the cranial cruciate ligament in the dorsal (H (2) = 19.620, P = 0.000), axial (H (2) = 14.633, P = 0.001), and sagittal (H (2) = 8.143, P = 0.017) planes were significantly affected by the angle of stifle flexion. Post hoc analysis showed that the ligament was best visualized at 90° compared to 145° in the dorsal (Z = -3.906, P = 0.000), axial (Z = -3.398, P = 0.001), and sagittal (Z = -2.530, P = 0.011) planes. Findings supported the use of a 90° flexed stifle position for maximizing visualization of the cranial cruciate ligament using low-field MRI in dogs.

A 12 yr old castrated male mixed-breed dog presented with a 2 wk history of progressive tetraparesis. Neurologic deficits included a short-strided choppy gait in the thoracic limbs and a long-strided proprioceptive ataxia in the pelvic limbs. Withdrawal reflexes were decreased bilaterally in the thoracic limbs. Signs were consistent with a myelopathy of the caudal cervical/cranial thoracic spinal cord (i.e., the sixth cervical [C] vertebra to the second thoracic [T] vertebra). A mass associated with the C6-C7 articular facet on the left side was identified on MRI of the cervical spinal cord. The lesion was hyperintense to spinal cord parenchyma on T2-weighted images, hypointense on T1-weighted images, and there was strong homogenous contrast enhancement. Significant spinal cord compression was associated with the lesion. The mass was removed through a C6-C7 dorsal laminectomy and facetectomy. Histopathology of the mass was consistent with a synovial myxoma of the articular facet. A postoperative MRI showed complete surgical resection. Albeit rare, synovial myxomas should be included in the list of differential diagnoses for neoplasms affecting the vertebral columns in dogs.

Low-field MRI (lfMRI) has become increasingly accepted as a method for diagnosing canine meniscal tears in clinical practice. However, observer effects on diagnostic accuracy have not been previously reported. In this study, 50 consecutive stifle joints with clinical and radiologic evidence of cranial cruciate ligament insufficiency were investigated by lfMRI and arthroscopy. Fifteen observers who had varying levels of experience and who were unaware of arthroscopic findings independently reviewed lfMRI studies and recorded whether lateral and medial meniscal tears were present. Diagnostic accuracy (sensitivity, specificity, positive (PPV) and negative predictive value (NPV)) was determined for each observer and median values were calculated for all observers, using arthroscopy as the reference standard. Interrater agreement was determined based on intraclass correlation coefficient (ICC) analysis. Observer level of experience was compared with diagnostic sensitivity and specificity using correlation analysis. Based on pooled data for all observers, median sensitivity, specificity, PPV, and NPV for lfMRI diagnosis of lateral meniscal tears were 0.00, 0.94, 0.05, and 0.94, respectively. Median sensitivity, specificity, PPV, and NPV for medial meniscal tears were 0.74, 0.89, 0.83, and 0.79, respectively. Interrater agreement for all menisci was fair (0.51). Menisci were less consistently scored as having no tears (ICC = 0.13) than those scored as having tears (ICC = 0.50). No significant correlations between observer experience and diagnostic sensitivity/specificity were identified. Findings indicated that the accuracy of lfMRI for diagnosing canine meniscal tears was poor to fair and observer-dependent. Future studies are needed to develop standardized and widely accepted lfMRI criteria for diagnosing meniscal tears.

Spinal MR images acquired from canine patients over a 7-year period were reviewed for the presence of vertebral endplate changes. Seventy-five dogs with 76 distinct lesions were identified. Presumptive diagnoses fell into five categories: reactive endplate changes (10 dogs/13.2%), discospondylitis (29 dogs/38.2%), vertebral osteochondrosis (7 dogs/9.2%), intravertebral disc herniation (Schmorl's nodes) (4 dogs/5.3%), and fatty infiltration (26 dogs/34.2%). Fatty infiltration occurred significantly more often in small breed dogs (P < 0.001) and tended to be multifocal. The following features were observed in discospondylitis as well as in other nonfatty endplate pathologies: irregular endplates, endplate hyperintensity in T2w or STIR images, reduced endplate signal intensity in T1w SE, variable T1w GRE signal intensity, and endplate contrast enhancement. Overlap between MR characteristics of nonfatty endplate changes should prompt cautious evaluation of adjacent structures.

SummaryThe spleen is a critical organ in defence against haemoparasitic diseases like babesiosis. Many in vitro and ex vivo studies have identified splenic cells working in concert to activate mechanisms required for successful resolution of infection. The techniques used in those studies, however, remove cells from the anatomical context in which cell interaction and trafficking take place. In this study, an immunohistological approach was used to monitor the splenic distribution of defined cells during the acute response of naïve calves to Babesia bovis infection. Splenomegaly was characterized by disproportionate hyperplasia of large versus small leucocytes and altered distribution of several cell types thought to be important in mounting an effective immune response. In particular, the results suggest that the initial crosstalk between NK cells and immature dendritic cells occurs within the marginal zone and that immature dendritic cells are first redirected to encounter pathogens as they enter the spleen and then mature as they process antigen and migrate to T‐cell‐rich areas. The results of this study are remarkably similar to those observed in a mouse model of malarial infection, suggesting these dynamic events may be central to the acute response of naïve animals to haemoparasitic infection.

ObjectiveTo evaluate: (1) an arthroscopic technique for transection of the collateral sesamoidean ligament (CSL); and (2) the healing response using magnetic resonance (MR) and microscopic examination.Study DesignExperimental study.AnimalsAdult horses (n=6).MethodsSix sound horses with normal front foot radiographic and MR examinations were used. Lameness examination was performed before surgery and monthly for 12 months. Front foot radiography was performed at 180 and 360 days after surgery. Front foot MR was performed before, and at 7, 90, 180, and 360 days after surgery. Arthroscopic CSL desmotomy was performed on 1 forelimb. Gross and microscopic examination was performed on the CSL from both forelimbs at 360 days after surgery. Lameness scores were compared over time using the nonparametric Friedman's test for paired groups. CSL measurements were compared using paired t-tests with a 2-tailed significance level of P <.05.ResultsRadiographs remained normal throughout study period. Surgery resulted in lameness on the operated limb for up to 2 months, after which all horses returned to soundness. CSL transection was confirmed during arthroscopy and with MR examination 7 days after surgery. Gross and microscopic evaluation confirmed ligament healing.ConclusionsCSL desmotomy resulted in short-term lameness after surgery followed by healing of the CSL confirmed by gross and microscopic analysis.

Aandoeningen van de hersenen komen zelden voor bij paarden.De diagnose, de uitbreiding van de pathologie en de eventuele planning van de chirurgische behandeling kunnen bepaald worden aan de hand van magnetic resonance imaging (MRI).Enkele congenitale aandoeningen, zoals Dandy-Walker-Like (DWS) syndroom en hydrocephalus, geven een typisch MRI-beeld, net zoals bloedingen, oedeem en infectie.Een tumor, hematoom, cyste en een abces zijn ruimte-innemende processen die elk hun specifieke eigenschappen hebben en daardoor een ander beeld geven op T1 en T2.De meest voorkomende tumoren zijn chole s terolgranuloma's van de plexus choroideus, hypofysetumoren en metastasen vanuit de neus, sinussen, het oog of een andere primaire tumor in het lichaam.MRI is de enige ante mortem techniek die gebruikt kan worden voor het stellen van de diagnose van equine nigropallidale encefalomalacia.

Central nervous system (CNS) tumors are relatively common in veterinary medicine, with most diagnoses occurring in the canine and feline species. Numerous tumor types from various cells or origins have been identified with the most common tumors being meningiomas and glial cell tumors. Radiation therapy is often used as an aid to control the clinical signs associated with these neoplasms. In general, these tumors have a very low metastatic potential, such that local control offers substantial benefit. Experience in veterinary radiation oncology would indicate that many patients benefit from radiation treatment. Current practice indicates the need for computed tomography or magnetic resonance imaging studies. These highly beneficial studies are used for diagnosis, treatment planning, and to monitor treatment response. Improvements in treatment planning and radiation delivered to the tumor, while sparing the normal tissues, should improve local control and decrease potential radiation related problems to the CNS. When possible, multiple fractions of 3 Gy or less should be used. The tolerance dose to the normal tissue with this fractionation schedule is 50 to 55 Gy. The most common and serious complications of radiation for CNS tumors is delayed radiation myelopathy and necrosis. Medical management of the patient during radiation therapy requires careful attention to anesthetic protocols, and medications to reduce intracranial pressure that is often elevated in these patients. Canine brain tumors have served as an experimental model to test numerous new treatments. Increased availability of advanced imaging modalities has spawned increased detection of these neoplasms. Early detection of these tumors with appropriate aggressive therapy should prove beneficial to many patients.