Primary and metastatic intraaxial brain tumors: prospective comparison of multivoxel 2D chemical-shift imaging (CSI) proton MR spectroscopy, perfusion MRI, and histopathological findings in a group of 159 patients.

BACKGROUND: This study aims to assess the diagnostic value of multivoxel 2D chemical-shift imaging (CSI) proton magnetic resonance (MR) spectroscopy combined with perfusion magnetic resonance imaging (MRI) in the differential diagnosis and grading of brain tumors by comparing neuroimaging data with histopathological findings obtained after resection or biopsy. METHODS: A total of 159 patients with a previous brain tumor diagnosis underwent multivoxel 2D CSI proton MR spectroscopy and perfusion MRI. MR spectroscopy multivoxel 2D CSI was performed with an echo time of 30, TR 1,500, FOV 160 mm, acquisition time 7 min 34 s. rCBV maps were evaluated during postprocessing. Statistical analysis was performed on the examination of distributive normality, with logarithmic transformations, Fisher's test, and Bonferroni's test. We used the Pearson's test to compare percentages. RESULTS: In the differential diagnosis between GBM and metastases, MR spectroscopy multivoxel 2D CSI, combined with dynamic contrast enhanced MRI (DCE-MRI) perfusion, reached high sensibility and specificity (p < 0.000001). In brain tumor grading, the same method reached high sensibility and specificity (p < 0.000001) in distinguishing grade III-IV gliomas but encountered difficulty in determining grades within the two main groups of primary brain tumors, especially where mixed gliomas were involved. CONCLUSIONS: The systematic use of CSI spectroscopy and perfusion imaging has shown a high potential in the differential diagnosis and grading of brain tumors. Further exploration into diagnostic procedures that can significantly distinguish between grade III-IV and grade II tumors is needed.

Asymptomatic Carriers of Presenilin-1 E318G Variant Show no Cerebrospinal Fluid Biochemical Signs Suggestive of Alzheimer's disease in a Family with Late-onset Dementia.

BACKGROUND: Presenilin-1 (PSEN-1) is a component of the γ-secretase complex involved in ß-amyloid Precursor Protein (AßPP) processing. Usually, Alzheimer's disease (AD)-linked mutations in the PSEN-1 gene lead to the early onset and increase the production of the aggregation-prone peptide Aß42. However, the PSEN-1 E318G variant has an unclear pathogenic role and is recently reported as a genetic risk factor for AD. In particular, E318G variant presence correlated with increased cerebrospinal fluid (CSF) levels of Total Tau (t-tau) and Phosphorylated Tau (p-tau). OBJECTIVE: We describe a large Italian family, which we followed from January 2003 to January 2018, with the late-onset AD and the E318G variant, with the aim of assessing E318G-associated CSF or plasma biochemical changes in biomarkers of dementia. METHOD: CSF Aß42, t-tau and p-tau, plasma Aß42 and Aß40 were assessed by ELISA tests, while CSF amyloid peptides profile was investigated by mass spectrometry. RESULTS: We did not find any changes in CSF biochemical markers (Aß42, t-tau, p-tau and amyloid peptides) of asymptomatic E318G carriers in 2010 and 2012, but plasma Aß40 was increased at the same times. From 2003 to 2018, no asymptomatic E318G carrier developed AD. CONCLUSION: Our follow-up of this family may help elucidate E318G's role in AD and globally points to a null effect of this variant.