Brain scintigraphy was performed using 99mTc-Albumin Microspheres (99mTc-AMS) for study of microcirculation of cerebral ischemic lesions.99mTc-AMS was injected into carotid arteries and/or vertebral arteries respectively, and brain scintigram was obtained with routine method.
99mTc-AMS scintigraphy was performed 54 times for 30 patients with cerebrovascular ischemic disease. Complications due to injection of 99mTc-AMS were not seen except only one patient who developed transient motor dysphasia.
Patent vascular beds corresponding to the particle sizes of AMS were visualized on 99mTc-AMS scintigrams and therefore, ischemic area was clearly revealed.
“Functional”watershed area was visualized on the colour displayed 99mTc-AMS scintigrams as an overlapped area, and it shifted following the changes of cerebral hemodynamics (collateral circulations). Cortical ischemic lesions are seemed to be developed at these functional watershed areas if perfusion pressure is insufficiently low. So, in cortical ischemic lesions detected by these scintigrams, there seemed to have an indication of surgical revascularization at the favourable phase.
In some cases, the collapse of microvasculature and/or the presence of arteriovenous shunts were demonstrated by the findings of 99mTc-AMS scintigrams using different sizes of microspheres. For these cases with completely obstructed changes of cerebral microvasculature, there seems to have no indication for surgical revascularization.
99mTc-AMS scintigram is thought to be very useful for the recognition of cerebral microcirculation especially at the ischemic lesions in situ.
