Comparison of Computed Tomography and Myelography to a Reference Standard of Computed Tomographic Myelography for Evaluation of Dogs with Intervertebral Disc Disease

Abstract

Objective To compare the sensitivity of computed tomography (CT) and myelography to a reference standard of CT myelography for determining localization of Type I intervertebral disc extrusions in dogs. Study Design Prospective blinded comparative study. Animals Dogs with acute onset myelopathy because of suspected disc extrusions (n = 30). Methods Dogs had CT, myelography, and CT myelography to diagnose disc extrusions. Sensitivity of CT and myelography was compared to CT myelography for lateral, longitudinal, and combined localization. Confidence in the assessment of each imaging study was scored by 3 reviewers. Results Sensitivity of CT for lateral, longitudinal, and combined localization was 94%, 91%, and 81%, respectively, and was 64%, 74%, and 53%, respectively for myelography. Sensitivity of all 3 categories of localization was significantly different between modalities (P < .0001, P = .0031, P < .0001). Significant differences in the sensitivity of lateral and combined localization were found between confidence scores for myelography (P < .0001, P < .0001). Significant differences in the sensitivity of lateral, longitudinal, and combined localization were found between confidence scores for CT (P = .011, P = .013, P = .027). Poor sensitivity was obtained for both modalities except when imaging studies were assigned the highest confidence score. Conclusions CT is a more sensitive imaging technique than myelography for localizing disc extrusions when compared to a reference standard of CT myelography. Both modalities yielded high sensitivity with the highest confidence score and poor sensitivity for all other confidence scores.

The accuracy of the patellar reflex for localization of the site of a single level thoracolumbar disc herniation in dogs

“…CT is more sensitive than myelography in chronically affected dogs, while myelography is more sensitive than CT in small-sized dogs (<5 kg) (25,26). Moreover, the sensitivity of myelography for localization of lesions in dogs with intervertebral disc disease ranged from 53% to 94.7% (26)(27)(28), while the sensitivity of conventional CT for the detection of the site of lesions in dogs ranged from 81% to 100%, as reported in previous studies (26)(27)(28)(29). The range of the values of CT sensitivity may be due to CT's ineffectiveness in the diagnosis of conditions that do not involve mineralization of extruded disc material (30).…”

Using geographical information system for spatial evaluation of canine extruded disc herniation

“…CT represents a reliable, non-invasive diagnostic imaging modality useful for localisation and characterisation of EDH in dogs (Israel et al, 2009;Newcomb et al, 2012). In our study, the CT was used to differentiate the Hansen type I disc herniation and to define the actual location of the extruded disc material inside the VC.…”

Mielografia lombar no diagnóstico de extrusão do disco intervertebral toracolombar em cães: estudo prospectivo

“…A precisão relatada com uso da mielografia é de 72 a 97% para a localização da lesão e 53 a 100% para a lateralização da lesão nas extrusões discais (KIRBERGER; ROOS; LUBBE, 1992;SCHULZ et al, 1998;GIBBONS et al, 2006;BOS et al, 2007;NEWCOMB et al, 2012).…”

“…A principal complicação associada à punção cervical é a penetração da agulha espinhal na medula cervical ou no tronco encefálico levando a parada respiratória, além do aumento considerável do risco de convulsões pós-exame (DA COSTA; PARENT; DOBSON, 2011). A mielografia lombar, por sua vez, é tecnicamente mais exigente do que mielografia cervical, porém é mais acurada na identificação de lesões toracolombares, e apresenta menor risco de convulsões HOULTON, 1994). De acordo com McCartney (1997), punções até T13-L1 podem ser realizadas e produzir uma mielografia diagnóstica, no entanto, punções craniais a L5 podem levar a canalograma em 4,4 a 20% dos casos, com piora potencial dos déficitis neurológicos (KIRBERGER;ROOS;LUBBE, 1992;McCARTNEY, 1997).…”

“…O meio de contraste mais utilizado na medicina veterinária é o iohexol (DA COSTA; PARENT; DOBSON, 2011). A incidência de convulsões pós-mielografias com iohexol varia de 0 a 10% e tem sido associada com o peso do paciente (pacientes maiores), o volume de injeção de contraste (volumes maiores), a injeção na cisterna magna, localização da lesão (cervical mais provável), sexo (maior risco em machos) e raça (maior risco em dobermans pinchers) (WHEELER; DAVIES, 1985;LEWIS;HOSGOOD, 1992;HOULTON, 1994;ALLAN;WOOD, 1988;BARONE et al, 2002;DA COSTA;PARENT;DOBSON, 2011;NEWCOMB et al, 2012). A injeção do contraste em L5 e L6 para a mielografia em cães mais leves que 20 kg está associada com taxas mais baixas de convulsão pós-mielografia (BARONE et al, 2002;ISRAEL et al, 2009).…”