Effect of barrier opening on brain edema in human brain tumors

Blood-brain barrier (BBB) opening was carried out in 10 patients with cerebral lesions, and the MRI findings were evaluated following the barrier opening. An intra-arterial injection of 10% glycerol (4 ml/kg, 1 approximately 2 ml/s) was given as a hyperosmotic solution. T2-weighted MRI was undertaken using a TOSHIBA 22A at 30 minutes after BBB opening. Barrier-opening MRI was performed 10 times in 10 patients, including 5 cases of glioblastoma multiforme, 2 cases of astrocytoma, 1 case of malignant lymphoma, 1 case of cerebral contusion and 1 case of neurinoma. The high-intensity area (HIA) was compared with that in MRI without barrier opening. Three types of changes of HIA in MRI were observed after BBB opening as follows. Type 1: Expansion of the HIA was noted in 4 of 5 cases of glioblastoma multiforme, the 1 case of malignant lymphoma and the 1 case of cerebral contusion. Type 2: Almost no change was observed in the 1 case of neuronoma. Type 3: A decrease in HIA was noted in the 2 cases of astrocytoma and in 1 case of glioblastoma multiforme. The MRI following BBB opening evidently showed 3 types of changes according to the degree of BBB disruption. Glioblastoma multiforme or contusion with a severely disrupted BBB revealed an increase in HIA following barrier opening. Benign posterior fossa neurinoma showed no change in HIA after barrier opening. Moderate malignant tumors exhibited a decrease in HIA on barrier-opening MRI. It was concluded that malignant tumors have a severely damaged BBB, which is readily disrupted by osmotic barrier opening.