Diffusion Tensor Imaging of the Normal Cervical and Thoracic Pediatric Spinal Cord

Abstract

BACKGROUND AND PURPOSE: DTI data of the normal healthy spinal cord in children are limited compared with adults and are typically focused on the cervical spinal cord. The purpose of this study was the following: to investigate the feasibility of obtaining repeatable DTI parameters along the entire cervical and thoracic spinal cord as a function of age in typically developing pediatric subjects; to analyze the DTI parameters among different transverse levels of the cervical and thoracic spinal cord; and to examine the sex differences in DTI parameters along the cervical and thoracic spinal cord.

Characterization of spinal cord diffusion tensor imaging metrics in clinically asymptomatic pediatric subjects with incidental congenital lesions

“…The iFOV sequence was optimized for both signal and scan duration to image the entire pediatric SC. High inplane resolution axial diffusion-weighted images were acquired in the same anatomical location prescribed for the T2-weighted GRE to cover the cervical (C1-upper thoracic region) and thoracic (upper thoracic-L1) SC using two overlapping slabs that ensured complete coverage [13]. The imaging parameters for each slab of DTI acquisition included: FOV = 164 mm, phase FOV = 28.4% (47 mm), three averages of 20 diffusion directions images were acquired in addition to 6b0 images, b-value = 800 s/mm 2 , voxel size = 0.8 × 0.8 × 6 mm 3 , axial slices = 40, TR = 7900 ms, TE = 110 ms, and acquisition time = 8:49 min.…”

Zonally Magnified Oblique Multislice and Non-Zonally Magnified Oblique Multislice DWI of the Cervical Spinal Cord

“…Each ROI was drawn within 1-2 voxels of the cord boundary to prevent partial volume effects from the nearby cord/CSF junction. 3 Figure 1 shows the mean size of the ROIs at each intervertebral disc level in all subjects.…”

“…1,2 Despite these challenges, single-shot EPI offers a short acquisition time that decreases the probability of motionrelated artifacts, making this technique most appealing for clinical imaging of the spinal cord. 3 Recently, reduced FOV imaging sequences have generated valuable spinal cord imaging data. Diffusion-weighted imaging sequences like the zonally magnified oblique multislice (ZOOM) sequence have used this reduced FOV to acquire diffusion metrics in the spinal cord.…”

“…Diffusion-weighted imaging sequences like the zonally magnified oblique multislice (ZOOM) sequence have used this reduced FOV to acquire diffusion metrics in the spinal cord. 3,4 The impetus was to create a ZOOM acquisition that could replace the standard full-FOV method for clinical use. This is predicated on the goal of keeping acquisition times as close to or less than those of conventional full-field DTI techniques, with superior results.…”

“…It has been shown that in nearly all these instances, the reduced FOV EPI DTI method provides an increase in the signal-to-noise ratio compared with conventional full-FOV EPI techniques (non-ZOOM). 3,5,6 Using these techniques, several researchers have been able to acquire more precise diffusion metrics using ZOOM DTI sequences. In 1 study, ZOOM DTI increased diagnostic confidence in 33% of clinical examinations in a sample size of 180 clinical scans.…”