Quantifizierung des Embolisationseffektes bei intrakraniellen Meningeomen mittels T2*-gewichteter MR-Perfusionsmessung

Abstract

30 A. Bock et al.: MR-Perfusionsmessung bei intrakraniellen MeningeomenKlin Neuroradiol 1998;8:30--4,1 (Nr I) Quantification of the Embolization Effect in Intracranial Meningeomas by T2*-Weighted MR-Perfusion MeasurementSummary. It is the aim of this investigation to test if the MR-perfusion measurement is suitable for the quantification of the embolization effect in intracranial meningeomas and if areas with residual perfusion after percutaneous transarterial embolization (PTE) can be identified. Preoperative stepwise PTE with PVA particle suspension was performed in 23 patients (15 female, 8 male, ages: 34 to 82 years) with 24 intracranial supratentorial meningeomas (basal: 9, convexity: 8, falx: 7; 3.5 to 9.0 cm in maximum diameter). The perfusion studies were performed with a contrast enhanced fast T2*-weighted FFE-sequence before and 24 to 48 h after PTE. A calculation algorithm for the adjustment of interstitial contrast media distributions was developed in order to calculate the perfusion data. Dependent on the size of the meningeoma up to 3 ROI (matrix, centre and periphery close to cortex) were referenced against the contralateral cortex. The detected reduction of perfusion after PTE was matched with angiographical data (reduction of perfusion, additional pial-cortical feeding). The perfusion of meningeomas with angiographical detectable pial-cortical supply (pcF, 11/24) is well-balanced over all regions. In meningeomas without pcF (13/24) centre and pe¡ show a significant lower perfusion if compared to the matrix (p < 0,05). The reduction of perfusion after PTE by MR-perfusion measurement in the matrix and centre is comparable (65 vs. 76%), regardless of the entire estimation in angiography. However, residual perfusion in periphery is significantly higher (p < 0,05). This is caused either by a low entire perfusion of meningeoma and/or by additional pial-cortical supply. The MR-perfusion measurement controls the result of PTE at intracranial meningeomas with effectiveness. Significantly perfused regions following PTE can be identified. Insights into the supplying role of different feeding areas ate gained. In meningeomas with low perfusion and/or additional pial-cortical supply the PTE effect on the periphery close to the cortex is frequently missed.

Signal analysis of impulse response functions in MR and CT measurements of cerebral blood flow

“…The measured signal of a tissue with a permeable blood brain barrier (e.g., brain tumor) consists of a diffusive and a perfusive part [5,8]. The idea here is to split up these parts and deconvolve them separately.…”

“…However, a small portion diffuses into the extravascular space and then back into the intravascular space due to the defective blood brain barrier. Because diffusion is much slower than perfusion, contrast medium molecules still diffuse into the extravascular space during recirculation [5,8,15].…”