Biomedical Engineering Reference
In-Depth Information
its effects on changes to the shape of the brain were studied. Also the appear-
ance of growth and development in children needed to be identified.
Another unexpected finding was a reduction in brain size (atrophy rather
than edema) during the third trimester in patients with pre-eclampsia. Also
observed were atrophic change and swelling in first episode schizophrenia
over a 6 to 12 month period. Many other applications of this technique are
possible and results are awaited with considerable interest.
7.9
Physiological Changes
7.9.1
Effect of Head Position
Figure 7.16 shows interplateau and border zone shifts produced by changing
head orientation from right-side down to left-side down. The image shows
shift of the ventricular system and changes in many gyri. These changes may
provide a basis for measuring brain compliance in health and disease, includ-
ing quantification of the elastic properties of the brain.
7.9.2
Menstrual Cycle
In the four females studied, registration of repeated examinations showed
very small changes. The most consistent finding on the difference images was
a border zone shift related to the lateral ventricles consistent with an increase
in their size at the end of the second half of the menstrual cycle. This change
FIGURE 7.16
Change in the superior sagittal and straight sinuses with head flexion: Sagittal T1-weighted
images in upright position (a) and with head flexion (b). The registered difference image
[(b)
(a)] is shown in (c). The signal from the inferior sagittal sinus has increased, probably as
a result of an increase in size. The superior sagittal sinus shows a more complex change poste-
riorly (c). Border zone shifts are noted in the region of the superior cerebral sulci (c) (arrows).
