Table 5.
Diagnostic imaging protocols for investigation of CM and SM.
| Area | Sequence | Assessment of |
|---|---|---|
| ESSENTIAL PROTOCOL | ||
| Brain and craniocervical junction | - TW2 (high field) or T1W (low field) sagittal and transverse - Maximum slice thickness 4 mm |
- Conformation brain and craniocervical junction - CSF spaces - Other differential diagnoses |
| Cervical vertebral column | - TW2 and T1W sagittal - TW2 (high field) or T1W (low field) transverse with the block perpendicular to the spinal cord though the maximum width of the syrinx if SM is present, or as a block centred on C3 and extending from at least mid-point of the vertebral body of C2 - Maximum slice thickness 4 mm |
- Presence of SM, central canal dilation, spinal cord edema (presyrinx) - Measurement of maximum transverse width SM - Spinal cord dorsal horn involvement by SM - CSF spaces including cisterna magna - Other differential diagnoses |
| Thoracic vertebral column | - TW2 (high field) or T1W (low field) sagittal with or without transverse with the block perpendicular to the spinal cord though the maximum width of the syrinx if SM is present. Maximum slice thickness 4 mm | - Presence of SM or central canal dilation - Measurement of maximum transverse width SM - Spinal cord dorsal horn involvement by SM - Subarachnoid space - Other differential diagnoses |
| ADDITIONAL OR ALTERNATIVE SEQUENCES | ||
| Brain and craniocervical junction | - Three-dimensional, T1-weighted, gradient-echo sequence (MPRAGE) - Maximum slice thickness 1mm. |
- Used by the authors as an alternative to T1W spin echo sagittal and transverse |
| - Fluid-attenuated inversion recovery (FLAIR) - Maximum slice thickness 4 mm |
- To assess potential periventricular hyperintensive lesions for example with acute hydrocephalous or inflammatory disease | |
| Lumbar and lumbosacral vertebral column | - TW2 (high field) or T1W (low field) sagittal with or without transverse with the block perpendicular to the spinal cord though the maximum width of the syrinx if SM is present. Maximum slice thickness 4 mm | - If neurolocalization suggests and/or SM extends caudally to lumbar spinal cord and to investigate spinal cord tethering by the filum terminale if suspected |
| Area of suspected mass and /or spinal cord edema of unknown aetiology | - Paramagnetic contrast | - Cystic intramedullary tumours - Other differential diagnoses |
| Vertebral column | - Half-Fourier acquisition single-shot turbo spin-echo (HASTE) | - Used to some to make a more rapid assessment of the subarachnoid space |
| Area of suspected arachnoid web/band/dilatation | - Balanced steady-state free precession sequences (bSSFP) | - Recommended (high field)/essential (low field) to assess CSF space if arachnoid web suspected |
| - MRI flow studies (Cine MRI) | - Phase contrast cine MRI - Identify region of flow abnormalities/obstruction - Prognostication |
|
| - Cine bSSFP - Define the arachnoid webs or bands |
||
| - CT myelography | - If bSSFP and/or Cine MRI has not identified or not possible because of metal implants and if owner/veterinarian wishes to pursue possible surgical management | |
T1W—T1-weighted, TW2—T2 weighted. It is recommended that at the time of scanning that the microchip or tattoo number (confirmed by the veterinary surgeon) is included on the DICOM images in addition to the Kennel Club registration number if the dog is registered. This is to permit submission to an official CMSM health scheme should the owner request (33). The parameters for a 1.5 T machine are detailed in Supplementary File 1.