RESUMO
Imaging tumoral pH may help to characterize aggressiveness, metastasis, and therapeutic response. We report the development of hyperpolarized [2-13C,D10]diethylmalonic acid, which exhibits a large pH-dependent 13C chemical shift over the physiological range. We demonstrate that co-polarization with [1-13C,D9]tert-butanol accurately measures pH via13C NMR and magnetic resonance spectroscopic imaging in phantoms.
Assuntos
Isótopos de Carbono/química , Ácidos Dicarboxílicos/química , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Concentração de Íons de Hidrogênio , Imagens de FantasmasRESUMO
BACKGROUND AND PURPOSE: Super-resolution track density imaging generates anatomic images with submillimeter voxel resolution by using high-angular-resolution diffusion imaging and fiber-tractography. TDI within the diseased human brain has not been previously described. The purpose of this study was to correlate TDI with histopathologic features of GBM. MATERIALS AND METHODS: A total of 43 tumor specimens (24 contrast-enhancing, 12 NE, and 7 centrally necrotic regions) were collected from 18 patients with treatment-naïve GBM by use of MR imaging-guided neurosurgical techniques. Immunohistochemical stains were used to evaluate the following histopathologic features: hypoxia, architectural disruption, microvascular hyperplasia, and cellular proliferation. We reconstructed track density maps at a 0.25-mm isotropic spatial resolution by using probabilistic streamline tractography combined with constrained spheric deconvolution (model order, 8; 0.1-mm step size; 1 million seed points). Track density values were obtained from each tissue site. A P value of .05 was considered significant and was adjusted for multiple comparisons by use of the false discovery rate method. RESULTS: Track density was not significantly different between contrast-enhancing and NE regions but was more likely to be elevated within regions demonstrating aggressive histopathologic features (P < .05). Significant correlation between relative track density and hypoxia (odds ratio, 3.52; P = .01), architectural disruption (odds ratio, 3.49; P = .03), and cellular proliferation (odds ratio, 1.70; P = .05) was observed irrespective of the presence or absence of contrast enhancement. CONCLUSIONS: Numeric values of track density correlate with GBM biologic features and may be clinically useful for identification of regions of tumor infiltration within both enhancing and NE components of GBM.
Assuntos
Neoplasias Encefálicas/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Glioblastoma/patologia , Aumento da Imagem/métodos , Encéfalo/irrigação sanguínea , Mapeamento Encefálico/métodos , Hipóxia Celular , Núcleo Celular/patologia , Proliferação de Células , Forma Celular , Meios de Contraste , Citoplasma/patologia , Feminino , Humanos , Hiperplasia , Hipóxia Encefálica/patologia , Processamento de Imagem Assistida por Computador/métodos , Imuno-Histoquímica , Masculino , Microvasos/patologia , Pessoa de Meia-Idade , Necrose , Invasividade Neoplásica , Neuronavegação/métodos , Estudos Prospectivos , Radiologia Intervencionista/métodosRESUMO
SUMMARY: Time-resolved, 3D velocity-encoded MR imaging (4D Flow) allows for the acquisition of dynamic, multidirectional data on blood flow and has recently been used for the evaluation of intracranial arterial flow. Using a 3T system with optimization of both temporal resolution and k-space subsampling with a combination of parallel imaging and cut-corner acquisition, we present the clinical assessment of a patient with an arteriovenous malformation by providing complete intracranial arterial and venous coverage in a reasonable scan time.