Case Studies: MRI

Back – Spinal Dysiaphism Diastematomyelia

Introduction

• MRI is now the modality of choice for imaging the spine over CT and myelography
• Its multi-planar capabilities enable lesions to be diagnosed in three imaging planes - sagittal, coronal and axial
• Improved surface coils and faster gradients have increased resolution and scanning times to make MRI of the spine a valuable imaging tool
• Diastematomyelia is a spinal dysraphism with partial or complete sagittal spinal cord cleft
• The presence of a tethered cord can be clearly seen on T1W images that can highlight associated abnormalities such as an intradural lipoma

Patient History

• This is a 47 year old man with known “spina bifida”, with weakness in the legs and numbness in the groin
• He had a history of previous myelography and associated tests at a young age
• This patient was referred for MRI of the lumbar spine to assess spinal cord and presence of pathology

Methodology

• Sequences used:
  • T1W sagittal Turbo spin-echo: Pre and Post Gadolinium (fig 1)
  • T2W sagittal Turbo spin-echo (fig 2)
  • T1W axial Turbo spin-echo - Pre + Post Gadolinium (fig 3)
  • T2W axial Turbo spin-echo (figs 4 and 5)
  • Scanner: Siemens Magnetom Symphony 1.5 Tesla
  • Coil: CP Spine Array (S3-S6)

Report

• There is a loss of signal of the L5/S1 disc due to dehydration
• Mild posterior disc bulge is present at this level
• The lower lumbar sacral spinal canal and thecal sac are enlarged with abnormal fusion of the laminae at L4 and L5
• There is evidence of a low-lying tethered cord
• There is evidence of diastematomyelia with deviation of the cord by a septum that enhances with contrast media
• An area of altered signal within the left component of the divided cord with two small T1W high signal foci posterior to this are in keeping with small lipomas
• The altered signal within the left component of the cord may be due to a syrinx cavity, but the presence of a small dermoid cannot be excluded

Conclusion

• There is evidence of spinal dysraphism (i.e. diastematomyelia) involving the lumbar cord with evidence of a low-lying tethered cord

Fig 1

Fig 2

Fig 3

Fig 4

Fig 5

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