1. DIFFUSION TENSOR TRACTOGRAPHY OF THE SPINAL CORD
F. Gelbert
A. Henon, J.B. Gayet, N. Bouzar
M. Perrin, L. Balabaud
C. Mazel, R. Palau
PARIS (France)

2. Cervical spondylolis is found in 75% of patients over 65 years.
The most serious complication is cervical myelopathy, in 5% of patients suffering of spondylolis
The best treatment is surgery but clinical symptoms are at first discret.
MR T2 hyperintensity is observed often late in the course of the desease.

3. Cervical Myelopathy
Cervical myelopathy is caused by chronic segmental compression of the spinal cord because of spondylotic changes.
The initial cause is thought to be a continuous or intermittent compression or pinching of the cord, which results in chronic hypoperfusion.
Spondylotic
changes
Chronic
segmental
compression
Chronic
hypoperfusion
T2 hypersignal
vacuolization

4. Several study have assessed the feasability of diffusion techniques in spinal cord
In the spinal cord, white matter tracts are strongly organised in the cranio caudal direction so diffusion of water molecules is anisotropically oriented
The situation of the spinal cord in the spinal canal induce CSF and carotid flow artefacts and magnetic susceptibility artifacts cause by bone structures

5. 30 patients 15 males/15 females;
Age ranged from 34 to 79 years - mean age 50-65;
16 patients presented
with cervical and/or cervico brachial pain
14 presented
with walking impairement
and clinical suspicion of cervical myelopathy

6. MR Protocol Signa GE 1.5T HDxt MRI scanner
CTL coil in SAG T1, SAG T2 , AX T2
Diffusion protocol was performed using a SE EPI sequence in both
Sagittal and Axial plans
b value of 750 s/mm2
9 encoding directions

7. Post-Processing Diffusion Hypothesis:
In microscopic scale, water molecules randomly diffuses in isotropic environment (brownian motion) and in spinal cord water molecules diffuses mainly along fibers.
Method
Knowing diffusion direction it is possible to reconstruct fiber bundle of the spinal cord.

8. FA maps
Results
Fiber mapping
ADC Maps

9. Results 3 situations Normal examination : 9 patients
Focal cervical stenosis without spinal signal abnormality : 14 patients
Cervical stenosis and spinal signal abnormality: 6 patients
Other diagnosis: 1 SEP,1 syrinx

10. Situation 1- FA Cartography
:FA : normal values range from
Same results in axial and sagittal acquisition

11. Situation 1- ADC Cartography
Normal ranged from (0,9 – 1,20). 10-9
Same results in axial and sagittal acquisition

12. Fiber tracking

13. Situation 2 Ms A . 63 y. Upper limb paresis and cervical pain Cervical canal stenosis No signal abnormality
FA :
ADC: 0.9

14. Situation 2 Mr foug NCB . canal stenosis . No signal abnormalities
normal ADC and FA values

15. Situation 3 Canal stenosis and spinal signal abnormality
FA: 0.650
ADC= 1.1
ADC= 1.40
decreased FA: 0.32

16. Situation 3
FA:0.6
ADC:1.25
FA: 0.4
ADC: 1.45

17. Situation 3

18. Situation …. 4 Patient with arms weakness
Situation …..4 Patient with arms weakness. No T2 signal changes FA and ADC « abnormal values »
FA: 0.65
ADC:1.23
FA:0.4
ADC:1.50

19. Conclusion The calculation of FA and ADC was possible in all patients.
ADC and FA measurements were reproductible in a same patients with different reviewers and we obtained a constant average of value in normal spinal cord
We observed ADC and FA abnormal values in all cases of signal abnormalities

20. Conclusion
We also observed ADC and FA abnormal values in 5 patients with clinincal symptoms and no signal abnormality
This focuse the potential interest of this methods to detect earlier stages of spinal cord suffering
These preliminary results must encourage us to include this sequence in the MR protocol of potential spinal cord lesions
Axial or sagittal ? Both!!