Changes in cross-sectional measurements of the spinal canal and intervertebral foramina as a function of body position: In vivo studies on an open-configuration MR system
Mr. Schmid et al., Changes in cross-sectional measurements of the spinal canal and intervertebral foramina as a function of body position: In vivo studies on an open-configuration MR system, AM J ROENTG, 172(4), 1999, pp. 1095-1102
Citations number
24
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
OBJECTIVE, The purpose of this study was to evaluate physiologic changes of
the cross-sectional area of the spinal canal and neural foramina in young
asymptomatic volunteers.
SUBJECTS AND METHODS. Twelve asymptomatic volunteers were examined in a 0.5
-T open-configuration MR system. T2-weighted fast spin-echo sequences were
obtained in upright neutral, upright flexed, upright extended, and supine e
xtended positions. The cross-sectional area of the spinal canal and the thi
ckness of the ligamentum flavum were measured on angled axial images at the
L4-L5 level. The anteroposterior diameter of the spinal canal and cross-se
ctional areas of the neural foramina were measured on sagittal images from
L1 to S1,
RESULTS. At disk level, the cross-sectional area of;he spinal canal vaned s
ignificantly between body positions, most notably between the upright flexe
d (mean, 268 mm(2)) and the upright extended (mean, 224 mm(2)) positions (p
< .0001), The maximum thickness of the Ligamenta flava increased in the ex
tended positions (p < .0001). The cross-sectional area of the neural forami
na underwent position-dependent variations of as much as 44.4%. The smalles
t cross-sectional areas were found in the extended positions.
CONCLUSION. In asymptomatic volunteers, MR imaging is able to show position
-dependent changes in the cross-sectional areas of the spinal canal and the
intervertebral foramina, The extended positions best reveal important find
ings.