Artikel
Beyond morphometry. Perfusion weighted MR imaging (PWI) displays arterio-venous shunting as specific hemodynamic pathomechanisms in high grade glioma
Jenseits der Morphometrie. Die perfusions-gewichtete MRT (PWI) spiegelt spezifisch für hochgradige Gliome ein arterio-venöses Shunting als hämodynamischen Pathomechanismus wider
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Autoren
Veröffentlicht: | 23. April 2004 |
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Gliederung
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Objective
Highly malignant brain tumors often present a sudden onset of neurological symptoms due to their rapid displacing growth. Additionally there is a need for an increase in blood supply. However, as the amount of pathological neoangiogenesis may not be able to compensate for the rate of tumor growth, necrosis of the tumor center occurs, which is even more obvious in gliomas with enlarged tumor size. We investigated specific hemodynamic changes in the tumor and the surrounding and contralateral brain.
Methods
Using a bolus traced dynamic multislice T2*-weighted EPI MR perfusion technique (PWI, TR / TE = 2000 / 62 ms, FOV 240mm, matrix 128x128) on a 1.5 T Vision Scanner (Siemens, Erlangen, Germany) relative regional blood flow (rrCBF) and volume (rrCBV) were determined in 15 patients after determining the arterial input function.
Results
Both, rrCBV and rrCBF were increased in the grey matter compared to the white matter with a significant correlation between the two. There was no significant difference between the affected and the non-affected hemispheres. Highest values were always found in the tumor margin (p<0.001) with highly significant correlations of hemodynamic changes in the adjacent grey matter (rCBVt: R2=0,64; p<0,001; rCBFt: R2=0,58; p<0,001).
Conclusions
As demonstrated by conventional MR imaging, blood volume and flow is increased in the tumor margin, resulting in strong enhancement after i.v. contrast agent administration. Our data demonstrates that pathological new tumor vessels follow hemispheric hemodynamics, but steal blood by AV-shunting from the surrounding tissue to supply the tumor needs, which seems to be compensated by vascular autoregulation capacities at baseline conditions. Neurological symptoms could also occur because of a mismatch of blood supply and increased tumor demands to the disadvantage of the surrounding brain tissue.