QUANTITATION OF PERITUMOURAL EDEMA AND THE EFFECT OF STEROIDS USING NMR-RELAXATION TIME IMAGING AND BLOOD-BRAIN-BARRIER ANALYSIS

A new method of in vivo quantitation of peritumoural brain oedema usin g NMR relaxation time imaging (T1-maps) and Gd-DTPA-enhanced Blood-Tum our-Barrier (BTB) analysis is presented. The method is based on image pixel histogram analysis and a fast imaging method combined with arter ial [Gd-DTPA]-measurement. The method was applied in 26 brain tumour p atients, studied prior to - and 1, 3 and 7 days after initiation of de xamathasone. Oedema resorption rate following dexamethasone treatment was almost equal in glioblastomas and metastases, mean T1 being reduce d by ca. 12% in 7 days. In meningiomas no significant changes in perit umoural oedema could be detected. Simultaneous BTB-analysis was obtain ed in 4 patients showing correlation between oedema resorption in vivo and reduction of BTB transport rate constant K(i) after 7 days of ste roid treatment. This method is a powerful tool in quantitation and mon itoring of brain oedema in vivo, as both steroid influence on oedema r esorption and on BTB-defect can be monitored simultaneously.