ABSTRACT
Primary CNS lymphoma is difficult to diagnose with conventional imaging modalities. Magnetic resonance proton spectroscopy, dynamic susceptibility contrast DSC perfusion and diffusion weighted images have been recently investigated as a problem-solving tool for evaluation of primary CNS lymphoma with favorable results. To assess the value of advanced neuro-imaging [MR diffusion, perfusion and proton spectroscopy] in diagnosis of primary CNS lymphoma. Five adult patients with suspected primary CNS lymphoma [as suggested by clinical or conventional imaging techniques] were prospectively studied by magnetic resonance proton spectroscopy, dynamic susceptibility contrast DSC perfusion and diffusion weighted images aiming to confirm the suspected diagnosis. The examinations were done on 1.5T machines using diffusion weighted, dynamic susceptibility contrast perfusion and chemical shift CSI imaging sequences. Regarding DWI, all patients show low ADC value of 0.63 +/- 0.025[SD] x 10[-3] mm[2]/s, regarding the DSC perfusion. The max rCBV ratios are ranging from 0.23 to 1.52 with a mean ratio of 1.14 +/- 0.54[SD]. Regarding
ABSTRACT
Pilocytic astrocytomas are the second overall most common pediatric brain tumor. Magnetic resonance [MR] imaging is widely used in the diagnosis and follow up of pediatric patients with pilocytic astrocytomas because of its ability to provide anatomical detail. However conventional MR imaging does not provide information about tissue biochemistry. To study the role of proton magnetic resonance spectroscopy in diagnosis of pilocytic astrocytoma in children. This study included seven pediatric patients with histopathologically proven pilocytic astrocytoma. All patients were subjected to full history taking and thorough clinical examination. Magnetic resonance [MR] imaging was performed at 1.5 Tesla MR system using a standard head coil. Imaging included conventional MRI and proton magnetic resonance spectroscopy. Proton magnetic resonance spectroscopy was done using either single or multi-voxel technique. Surgical biopsy was then performed to all patients and correlation with histopathological data was done. Out of the seven patients included in this study, six were females and one was male with mean age of 9.5 years, the tumor was located in five of them in the posterior fossa, located in right thalamo-peduncular region in one patient and located in the hypothalamic-chiasmatic region in one patient. MR spectroscopic study showed the same findings in all the lesions including high Cho/NAA and Cho/Cr ratios [3.53 +/- 1.5] and [7.21 +/- 4.2], respectively, relative low concentration of creatine with increased NAA/Cr ratio [2.32 +/- 1.1]. Lactate doublet was detected in all cases while no lipid peaks were detected. Based on the findings in this study we suggest that pilocytic astrocytoma has a specific spectroscopic metabolic profile which could be diagnostic for this type of tumor