MRI evaluation of the hydration status of non-pathological lumbar intervertebral discs in a pediatric population.
INTRODUCTION
The intervertebral disc (IVD) is made up of the annulus fibrosus (AF) and the nucleus pulposus (NP) - an inert hydrated complex. The ability of the IVD to deform is correlated to that of the NP and depends on its hydration. As the IVD ages, its hydration decreases along with its ability to deform. In adolescent idiopathic scoliosis, one of the etiological hypotheses pertains to the IVD, thus making its condition relevant for the diagnosis and monitoring of this pathology.


HYPOTHESIS
IVD hydration depends on sex, age and spine level in an asymptomatic pediatric population. The corollary is data on a control group of healthy subjects.


MATERIAL AND METHODS
A cohort of 98 subjects with normal spine MRI was enrolled; their mean age was 13.3 years. The disc volume and hydration of each IVD was evaluated on T2-weighted MRI sequences, using previously validated image processing software. This evaluation focused on the lumbar spine, from the thoracolumbar junction to the lumbosacral junction. It was assumed that IVD hydration was related to the ratio of NP and AF volumes. A mixed multivariate linear analysis was used to explore the impact of age, sex and spinal level on disc hydration.


RESULTS
Disc hydration was higher overall in boys than in girls, but this difference was not significant. Hydration increased with age by +0.005 for each additional year (p=0.0213). Disc hydration appears to be higher at the thoracolumbar junction than the lumbar spine, although this difference was not significant.


CONCLUSION
Through this MRI study, we established a database of non-pathological lumbar disc hydration as a function of age, sex and spinal segment along with 95% confidence intervals.


LEVEL OF EVIDENCE
IV.
['Bolzinger|Manon|M|', 'Estivalèzes|Erik|E|', 'Gallini|Adeline|A|', 'Polirsztok|Eva|E|', 'Abelin-Genevois|Kariman|K|', 'Baunin|Christiane|C|', 'Sales de Gauzy|Jérôme|J|', 'Swider|Pascal|P|']
D000293:Adolescent D005260:Female D006801:Humans D007403:Intervertebral Disc D055959:Intervertebral Disc Degeneration D008159:Lumbar Vertebrae D008161:Lumbosacral Region D008279:Magnetic Resonance Imaging D008297:Male D012600:Scoliosis
MRI Intervertebral disc Image processing