Biomedical Engineering Reference
In-Depth Information
In monitoring the effect of treatment, effects of drugs on brain size need to
be recognized. In particular, steroids and ACTH may produce a change in
brain size due to treatment, not the primary pathologic process. Likewise,
alcohol and states of hydration may affect brain size.
7.18
Bone Marrow Transplantation
In order to determine the nature and frequency of changes to the brain in
patients undergoing chemoradiotherapy and BMT, we performed registered
serial MRI studies in 15 patients with CML (13 allografts and 2 autografts).
29
Repeated studies performed 4 to 339 days after transplantation showed
ventricular enlargement and cortical atrophy in all of the 13 patients who had
allografts. The changes were evident at 4 to 6 days, and became more obvious
in later follow-up cases. Similar changes were seen in one patient with an
autograft, but no significant change was seen in other autografted patients or
in the normal controls.
Cerebral atrophy has been described following long term administration of
steroids, and reversibility of the findings may follow decrease or cessation of
steroid use. The appearances are typically described with long term use (six
months to five years) and cumulative doses of 4000 to 58,000 mg of pred-
nisone. Assessing the potential effect of steroids is complex. All 15 patients in
this study had steroids at some stage in their illness. The total dosage for
allograft patients varied from the equivalent of 100 to 20,250 mg of predniso-
lone. There was no evidence of reversibility of ventricular size in any
patients. This might have been expected in patients having a reduction in
their dosage or stopping treatment with steroids. The onset of brain changes
occurred at the same time as treatment with steroids, cyclophosphamide, and
TBI, but there did not appear to be a particular association with steroids
given in the previous 48 hours.
7.19
Quantitation of Brain Change
Quantified measurement of the size of various brain structures and patholo-
gies can readily be achieved from MR images. A number of examples have
been cited in this chapter and many computerized tools are now available for
such measurements including some designed specifically for use in conjunc-
tion with registered images.
25,30,31
Although there may be technical problems
in achieving reliable quantitation for some structures, for example, due to
complexity of shape or ambiguity in the precise location of a boundary, in
many scientific and clinical serial studies a key prerequisite to measurement
