MR CBV maps provided diagnostic information not available with conventional MR imaging in six cases and offers a functional parameter for assessing glioma grade and regions of focal activity.
Neovascularization is a common phenomenon in gliomas. MR imaging cerebral blood volume (CBV) mapping utilizes ultrafast echo-planar imaging and simultaneous use of gadolinium-based contrast material. To determine the utility of MR CBV mapping in the clinical evaluation of gliomas, we followed 15 patients with serial studies. This technique provided functional information that was not evident with conventional CT or MR imaging. Low-grade tumors demonstrated homogeneously low CBV, while high-grade tumors often showed areas of both high and low CBV The maximum tumor CBV/white matter ratio was compared between low- (n = 3) and high-grade gliomas (n=5) in patients without previous treatment and with histologic verification (n=8) and was significantly higher in high-grade gliomas (p<0.01). High CBV foci in nonenhancing tumor areas were present in 2 cases. The distinction between radiation necrosis and active tumor could be made correctly in 3 of 4 cases. The information provided by MR CBV mapping has the potential to be an adjunct in the clinical care of glioma patients.
We intended to compare two-dimensional Fourier transform (2DFT) with three-dimensional Fourier transform (3DFT) multiple overlapping thin-slab acquisition (MOTSA) time-of-flight (TOF) magnetic resonance angiography for percent diameter stenosis, length of stenosis, and apparent occlusion at the carotid bifurcation. For that, 101 symptomatic patients (n = 202 carotid bifurcations) were evaluated with 3DFT MOTSA TOF and 2DFT TOF. Three observers measured the percent diameter stenosis from oblique axial multiplanar reformatted (MPR) images and length of stenosis from maximum intensity projection (MIP) images. Kappa analysis assessed interobserver agreement and the Wilcoxon signed rank test was used to compare the two MR angiographic techniques. There was a significant difference in the percent diameter stenosis (p < 0.01) and length of carotid stenosis (p < 0.01) between 2DFT and 3DFT MOTSA TOF magnetic resonance angiography. Stenosis was greater in 33% of carotid arteries and was upgraded (NASCET) in 17% of carotid arteries on the 2DFT TOF. The number of apparently occluded carotid arteries was equal with both MRA techniques. There was good agreement between the three observers (k = .50).
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