MRI Research Today is a free monthly online journal that collates and summarizes the latest research about MRI, including details on magnetic resonance imaging, neuroimaging, brain tumors. | ||||||||
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Evaluation of human brain tumor heterogeneity using multiple T1-based MRI signal weighting approaches.Donahue MJ, Blakeley JO, Zhou J, Pomper MG, Laterra J, van Zijl PC Russell H. Morgan Department of Radiology and Radiological Science, Neuroscience Section, Division of MR Research, Johns Hopkins University, 720 Rutland Avenue, Baltimore, MD 21205, USA. Vascular-space-occupancy (VASO) MRI without contrast injection was explored for imaging cerebral blood volume (CBV) and tissue heterogeneity in gliomas (n = 10). VASO contrast complemented contrast-enhanced T(1)-weighted (GAD-T(1)w), FLAIR and T(1)w magnetization-prepared-rapid-gradient-echo (MPRAGE) images. High-grade gliomas showed a VASO-outlined hyperintense zone corresponding to long-T(1) regions in MPRAGE and to nonenhancing regions in GAD-T(1)w images. FLAIR, MPRAGE, and VASO data were used to segment tumors into multiple zones of different T(1). After removal of known resection areas using pre- and postsurgical MRI, the volume of overlap between the hyperintense VASO-zone and the long-T(1) MPRAGE zone correlated with that of GAD-T(1)w enhancement (R(2) = 0.99) and tumor grade. Based on these correlations, this remaining long T(1) overlap area was tentatively assigned to necrosis. In one promising case the collective T(1)-weighted approach accurately identified a low-grade glioma despite the presence of contrast enhancement in GAD-T(1)w images consequential to chemoradiation-associated treatment effect. The results suggest that this collective T(1)-weighted approach may provide useful information for regional assessment of heterogeneous tumors and for guiding treatment-related decisions in patients with gliomas. Published 4 February 2008 in Magn Reson Med, 59(2): 336-44.
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