Changes in T2 Relaxation Times Associated with Maturation of the Human Intervertebral Disk
E.C. Kruegera,b,
J.O. Perryb,
Y. Wub and
V.M. Haughtona
a Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison Wis
b Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison Wis
View larger version (15K):
[in this window]
[in a new window]
|
Fig 1. Four selected images at TE of 19, 38, 56, and 75 ms from the modified FSE sequence illustrate the loss of signal intensity from the spinal tissues and L4-L5 disk with increasing TE. Disk tissue loses signal intensity less rapidly than vertebrae. The T2 relaxation time, the length of time required for the signal intensity to diminish by 50%, is calculated for each voxel from 16 such images.
| |
View larger version (82K):
[in this window]
[in a new window]
|
Fig 2. Sagittal MR image showing the placement of a region of interest (dotted line) and the line superior to inferior in the intervertebral disk along which T2 values were sampled and plotted as a function of distance to calculate the effect of the central region of low signal intensity on the T2 relaxation times.
| |
View larger version (24K):
[in this window]
[in a new window]
|
Fig 3. Sagittal T2-weighted MR images (A), color map of the T2 relaxation times in a sagittal section (B) and surface contour plot of T2 relaxation times in a sagittal section (C) for an L2-L3 disk in a 6-year-old subject (group 1). The plot shows the anterior edge of the disk to the reader's left and the posterior edge to the reader's right. The upper margin of the disk is toward the top of the page and the lower margin, toward the bottom. The plot shows highest values of T2 near the central portion of the disk. In the central region, the T2 values are relatively uniform.
| |
View larger version (27K):
[in this window]
[in a new window]
|
Fig 4. Sagittal T2-weighted MR images (A), color map of the T2 relaxation times in a sagittal section (B), and surface contour plot of T2 relaxation times in a sagittal section (C) for an L2-L3 disk in a 19-year-old subject, displayed in the same manner as Fig 3. This plot shows a band of diminished T2 values in the central portion of the disk, where fibrous tissue content increases during maturation of the disk. This band is found commonly in the 19- and 20-year-olds in this study and rarely in the younger subjects.
| |
View larger version (15K):
[in this window]
[in a new window]
|
Fig 5. T2 relaxation times on a line superior to inferior through the center of an L4-L5 disk in a 6-year-old subject and of an L2-L3 disk in a 19-year-old. This plot shows the CLSIR as a dip in the T2 relaxation times along the superior-inferior axis of the disk in the older subject. It also shows the relatively greater relaxation times of T2 in the older group. T2 relaxation times are shown on the vertical axis, and the distance from the superior endplate is shown along the horizontal axis.
| |
