Journal of neuroimaging : official journal of the American Society of Neuroimaging
-
Previous magnetic resonance spectroscopy (MRS) studies have concluded that hippocampal and parahippocampal metabolite concentrations remain stable during healthy adult aging. However, these studies used short repetition times (TR ≤ 2 seconds), which lead to incomplete longitudinal magnetization recovery, and thus, heavily T1 -weighted measurements. It is important to accurately characterize brain metabolites changes with age to enable appropriate interpretations of MRS findings in the context of neurodegenerative diseases. Our goal was to assess hippocampal brain metabolite concentrations in a large cohort of diversely aged healthy volunteers using a longer TR of 4 seconds. ⋯ We observed increases in hippocampal/parahippocampal metabolite concentrations with age, a finding that is in contrast to previous literature. Our findings illustrate the importance of using a sufficiently long TR in MRS to avoid T1 -relaxation effects influencing the measurement of absolute metabolite concentrations.
-
The objective of this study was to longitudinally investigate the trajectory of change in 1 H MRS measurements in asymptomatic MAPT mutation carriers who became symptomatic during follow-up, and to determine the time at which the neurochemical alterations accelerated during disease progression. ⋯ Our findings support the potential use of longitudinal 1 H MRS for monitoring the neurodegenerative progression in MAPT mutation carriers starting from the asymptomatic stage.
-
Multiple sclerosis (MS) clinical management is based upon lesion characterization from 2-dimensional (2D) magnetic resonance imaging (MRI) views. Such views fail to convey the lesion-phenotype (ie, shape and surface texture) complexity, underlying metabolic alterations, and remyelination potential. We utilized a 3-dimensional (3D) lesion phenotyping approach coupled with imaging to study physiologic profiles within and around MS lesions and their impacts on lesion phenotypes. ⋯ The association of lesion phenotypes with their metabolic signatures suggests the prospect for translation of such data to clinical management by providing information related to metabolic activity, lesion age, and risk for disease reactivation and self-repair. Our findings also provide a platform for disease surveillance and outcome quantification involving myelin repair therapeutics.
-
Studies have shown an association between infarct patterns and recurrent stroke in patients with symptomatic intracranial stenosis (sICAS) but there are limited data on associations with perfusion imaging mismatch profile. We aim to determine the association between infarct pattern, optimal mismatch profile definition, and recurrent cerebrovascular events (RCVE) in patients with anterior circulation sICAS. ⋯ IBZ infarcts may be a surrogate marker of distal perfusion status and RCVE risk. Larger multicenter, prospective, core-lab blindly adjudicated studies are needed to confirm our findings.
-
Meningiomas are the most common primary intracranial tumors, typically treated with surgery and adjuvant radiation in cases of subtotal resection and/or higher histopathologic grade. Contrast-enhanced magnetic resonance imaging (MRI) is the gold standard for postoperative assessment and adjuvant treatment planning. However, MRI can have limited accuracy particularly in the presence of posttreatment change. [68Ga]-DOTATATE is a Positron Emission Tomography (PET) radiotracer targeting somatostatin receptor 2A (SSTR2A). SSTR2A is a reliable biomarker of meningiomas. We report a consecutive case series of 20 patients evaluated with [68Ga]-DOTATATE PET/MRI, propose a novel approach to quantitative analysis, and discuss clinical implications. ⋯ [68Ga]-DOTATATE PET/MRI is a promising tool in the assessment of both treatment naïve and resected/irradiated meningiomas, allowing improved diagnosis and extent of disease evaluation. Future prospective studies are needed to determine utility of [68Ga]-DOTATATE PET/MRI in treatment response assessment.