Whole-spine magnetic resonance imaging study in healthy Chinese adolescents

Abstract

Objective: To establish a preliminary magnetic resonance imaging (MRI) database of whole spine of healthy Chinese adolescents.

Methods: MRI examination of whole spine and hindbrain was performed in 41 enrolled students aged 11-17 years (mean age 13.95; 18 males, 23 females) using a 1.5-T MR Scanner. Measurements of the ratio of anteroposterior (AP) and transverse (TS) diameters of the cord, cerebellar tonsillar level related to the basion-opsithion (BO) line, location of conus medullaris, total cord length, total vertebral length, cord/vertebral length ratio, thoracic cord area, thoracic vertebral area, thoracic cord/vertebral area ratio were obtained.

Results: Mean values of cervical AP and TS were 6.63 mm and 12.21 mm, respectively. The mean level of cerebellar tonsillar related to BO line was 3.97 mm. Mean level of conus medullaris located in L1 lower 1/3. Total cord length was 399.34 mm, total vertebral length was 529.49 mm, Cord/vertebral length ratio was 0.75 and thoracic cord/vertebral area ratio was 0.17 on average. Vertebral length was correlated with age (r = 0.352, P = 0.024) whereas cord length and their ratio were not (P > 0.05). Compared with female, male had significantly larger cervical AP and TS, longer cervical cord (P < 0.01), higher position of conus medullaris (P < 0.05).

Conclusion: MRI is a useful tool for assessment of the whole spine. The longitudinal and cross-sectional morphology of spinal cord in healthy Chinese adolescents may benefit further study of spine cord in adolescent idiopathic scoliosis as well as in other spine diseases.

Keywords: Adolescent; Magnetic resonance imaging; Spine cord; Whole‐spine.

Figure 1

The longest axis of the cord is taken for measuring the maximum transverse (TS) diameter of the cord, while the largest anteroposterior (AP) diameter of the cord is measured along a perpendicular axis to the transverse diameter. The AP/TS ratio is then calculated. (A) Thoracic cord area (B) Thoracic vertebral area, configuration and position of subarachnoid signal (C) Location of conus medullaris (D) Cerebellar tonsillar level related to the basion‐opsithion (BO) line, odontoid process level related to the BO line, angle between axis of medulla oblongata and cervical cord (α), angle between axis of medulla oblongata and BO line (β).

Figure 2

At the straightened best mid sagittal section of the vertebral column, length of vertebral column was measured from the tip of odontoid process (C₂) down to the inferior endplate of L₅ while length of cord was measured from the endplate of L₅ while length of cord was measured from the level of the tip of odontoid process (C₂) down to the conus medullaris.