Arq Neuropsiqutatr 1993, 51(3) :407-408
MAGNETIC RESONANCE IMAGING IN CERVICAL SPINAL
CORD COMPRESSION
GIOVANNI GIAMMONA, SALVATORE G I U F F R I D A , SALVATORE GRECO, CASIMIRO GRASSI, FRANCESCO L E P I R A
SUMMARY — I n p a t i e n t s w i t h cervical spondylotic myelopathy M R I sometimes shows increa-sed signal i n t e n s i t y zones on t h e T -weighted images. I t h a s been suggested t h a t these findings c a r r y prognostic significance. W e studied 56 subjects w i t h cervical spinal cord com-pression. Twelve p a t i e n t s showed an increased signal i n t e n s i t y (21.4%) and a prevalence of n a r r o w i n g of t h e A P - d i a m e t e r (62% vs 24%). F u r t h e m o r e , in t h i s group, t h e r e w a s evidence of a longer mean d u r a t i o n of t h e s y m p t o m s and, in most of t h e patients, of more serious clinical conditions. T h e i m p o r t a n c e of t h e s e p r e d i s p o s i n g factors remains, however, t o be clarified since they a r e also p r e s e n t in some p a t i e n t s w i t h o u t t h e increased signal intensity.
K E Y W O R D S : magnetic resonance imaging, cervical spondylotic myelopathy.
Ressonância magnética n a compressão d a medula cervical.
RESUMO — E m pacientes com mielopatia cervical espondilótica a ressonância magnética (RMN) à s vezes m o s t r a a l g u m a s zonas com sinal d e maior i n t e n s i d a d e n a s i m a g e n s em T> 2, q u e teriam
significado prognóstico. E x a m i n a m o s 56 pacientes com compressão da medula cervical. E m 12 havia h i p e r i n t e n s i d a d e (21,4%) e m a i o r incidência de e s t r e i t a m e n t o d o diâmetro ântero-posterior (62% c o n t r a 24%). Ainda, n e s t e g r u p o s e verificava d u r a ç ã o média m a i o r da sintomatologia e, n a m a i o r p a r t e dos pacientes, sinais clínicos m a i s graves. Todavia, a importância desses fatores deve a i n d a s e r esclarecida, pois estão p r e s e n t e s t a m b é m em a l g u n s pacientes que não a p r e s e n t a m a hiperintensidade.
PALAVRAS-CHAVE: ressonância magnética, mielopatia cervical espondilótica.
The value of magnetic resonance imaging (MRI) in the prognosis of
out-come from surgery of subjects with cervical spondylotic myelopathy has been
suggested by several authors The MRI shows increased signal intensity zones
on the T
2-weighted images in these patients. The aim of the present study is to
verify the incidence and clinical correlations of these findings and also a possible
pathogenesis.
MATERIALS AND M E T H O D S
All t h e p a t i e n t s examined were suffering from s y m p t o m s and signs of cervical myelo-pathy. I n all of t h e m t h e r e w a s neuroradiological evidence of cervical spinal cord compres-sion. W e studied fifty-six i n p a t i e n t s b y M R I w i t h a 0.5-Tesla superconducting m a g n e t (Philips gyroscan). T spin echo i m a g e s w i t h TRY 460 and TEA 30 and ^ - w e i g h t e d i m a g e s with TR1200 and T E from 50 t o 200 m s w e r e obtained. T h e high signal i n t e n s i t y on ^ - w e i g h t e d i m a g e s in cervical spinal cord w a s observed in twelve subjects (21.4%). P a t i e n t s w i t h o u t full clinical d a t a w e r e excluded. Among t h e eleven cases left w i t h altered signal w e selected eight p a t i e n t s (group 1). Two of t h e excluded u n d e r w e n t decompressive s u r g e r y a n d t h e t h i r d had a cervical t r a u m a . T h e control group, w i t h o u t altered signal, w a s m a d e u p of twenty-five
I n s t i t u t e of Clinical Neurology, University of Catania. Aceite: 2-março-1993.
patients (group 2). W e also examined age, sex, d u r a t i o n of symptoms, clinical d a t a (we used a scale, r a n g i n g from 0 t o 3), t y p e of compression (herniated disk or d i s k a r t h r o s i s ) and spinal cord stenosis. Clinical d a t a w e r e assessed b y a simple scale t h a t examined p y r a m i d a l signs, motor and sentory d i s t u r b a n c e s . W e gave one point for each of t h e t h r e e items. Therefore 0 means a negative neurological exam and 3 m e a n s the presence of all t h e t h r e e variables together. T h e A P - d i a m e t e r of the spinal cord w a s m e a s u r e d and d a t a compared w i t h normal values reported b y S h e r m a n et al.<5. Measurements were also obtained in a r e a s w i t h different signal intensity in t h e same subjects.
R E S U L T S
T h e t w o g r o u p s did n o t differ statistically a s to age (group 1: 54 ± 12.19; g r o u p 2: 54.08 ± 13.98) and sex ( g r o u p 1: 70% m a l e s ; g r o u p 2: 68% males). H e r n i a t e d d i s k s were present in 62% of g r o u p 1 and 40% of g r o u p 2 w i t h o u t significant differences ( p ^ 0.497). T h e r e w a s a significant difference as r e g a r d s t h e n a r r o w i n g of t h e spinal cord ( g r o u p 1: 62%; g r o u p 2: 24%; p < 0 . 1 ) and d u r a t i o n of symptoms (group 1: 30.37 ± 39.11 m o n t h s ; group 2: 11.80 ± 23.62; p ^ O . l ) . T h e m i n i m u m d u r a t i o n of s y m p t o m s w a s t h r e e m o n t h s in group 1. I n t h e same g r o u p d i s k a r t h r o s i s w a s a l w a y s associated w i t h n a r r o w i n g of t h e spinal cord. I t was not d e t e r m i n a n t t h e level of t h e cervical compression. I n all t h e p a t i e n t s in group 1 neurological signs w e r e p r e s e n t while these signs w e r e evident only in 52% of t h e subjects of g r o u p 2. Comparing subjects of g r o u p 1 and t h o s e of group 2 w i t h neurological s i g n s it was possible t o find a g r e a t e r severity in those of group 1 (group 1: 2 p o i n t s ; group 2: 1.46).
COMMENTS
Comparing our data with those of literature it is possible to find an
inci-dence of altered signal findings very similar to that reported by Takahashi et al.
(18.88% )7. in their study, however, the incidence of herniated disk was higher
than in ours. The importance of antero-posterior diameter of the spinal column
and duration of symptoms has already been reported L?. Those rather important
factors cannot, anyway, fully explain the abnormal signal. Six patients of group 2,
in fact, had a long duration of symptoms and a severe compression of the spinal
cord. Nevertheless, it is interesting that the clinical severity of these subjects
was lower than those of group 1 (1.33%). Thus, it is possible to suggest, together
with unknown individual anatomical factors, that in the presence of spinal cord
compression the duration of the compression itself plays a significant role. It is
also evident that the duration of compression cannot be assumed only knowing
the duration of clinical symptoms.
Conclusions. Though our data do not allow us to define pathogenetic
rea-sons of an altered signal the duration of compression is without doubt
impor-tant. It may be useful, then, in patients with increased signal intensity in
T
2-weighted images to consider a surgical decompression as soon as possible.
REFERENCES
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