Multiparametric 3T MR approach to the assessment of cerebral gliomas: tumor extent and malignancy.

INTRODUCTION: Contrast-enhanced MR imaging is the method of choice for routine assessment of brain tumors, but it has limited sensitivity and specificity. We verified if the addition of metabolic, diffusion and hemodynamic information improved the definition of glioma extent and grade. METHODS: Thirty-one patients with cerebral gliomas (21 high- and 10 low-grade) underwent conventional MR imaging, proton MR spectroscopic imaging ((1)H-MRSI), diffusion weighted imaging (DWI) and perfusion weighted imaging (PWI) at 3 Tesla, before undergoing surgery and histological confirmation. Normalized metabolite signals, including choline (Cho), N-acetylaspartate (NAA), creatine and lactate/lipids, were obtained by (1)H-MRSI; apparent diffusion coefficient (ADC) by DWI; and relative cerebral blood volume (rCBV) by PWI. RESULTS: Perienhancing areas with abnormal MR signal showed 3 multiparametric patterns: "tumor", with abnormal Cho/NAA ratio, lower ADC and higher rCBV; "edema", with normal Cho/NAA ratio, higher ADC and lower rCBV; and "tumor/edema", with abnormal Cho/NAA ratio and intermediate ADC and rCBV. Perienhancing areas with normal MR signal showed 2 multiparametric patterns: "infiltrated", with high Cho and/or abnormal Cho/NAA ratio; and "normal", with normal spectra. Stepwise discriminant analysis showed that the better classification accuracy of perienhancing areas was achieved when regarding all MR variables, while (1)H-MRSI variables and rCBV better differentiated high- from low-grade gliomas. CONCLUSION: Multiparametric MR assessment of gliomas, based on (1)H-MRSI, PWI and DWI, discriminates infiltrating tumor from surrounding vasogenic edema or normal tissues, and high- from low-grade gliomas. This approach may provide useful information for guiding stereotactic biopsies, surgical resection and radiation treatment.

MRI assessment of post-traumatic spinal instability.

The imaging evaluation of patients with spinal trauma has evolved over the past decades, and there has been particular interest in the concept of instability, to predict which a series of criteria have been proposed. We retrospectively evaluated the magnetic resonance imaging (MRI) findings in 50 patients with post-traumatic spinal instability according to Denis's three-column method, Daffner et al.'s radiographic criteria, and Oner et al.'s categorization of MRI findings; additionally, we evaluated the cord, the prevertebral tissue, and the epidural space. We suggest that an integrated panel of MRI information might be standardized in order to provide a more complete evaluation of spinal injury in an individual case and help planning surgical treatment.