Journal of neuroimaging : official journal of the American Society of Neuroimaging
-
The role of apparent diffusion coefficient (ADC) for preoperative grading and treatment planning of high-grade gliomas (HGG) is still debated since the assumption of inverse correlation between ADC and cellularity is not completely coherent with the results of some studies. It has been recently hypothesized that restricted diffusivity in HGG may be related to hypoxic/ischemic changes inside the tumor. We therefore investigated the differences of ADC values between areas with magnetic resonance spectroscopy (MRS) markers of hypoxia and necrosis (lactate and lipid compounds) and regions with lack of both metabolites. ⋯ HGG areas with MRS markers of hypoxia and necrosis are not associated with restricted diffusivity. To explain the trend to diffusion facilitation in HGG lactate-expressing regions, we hypothesize a possible hypoxia-induced volume reduction of glioma cells with extracellular shift of cytoplasmic water.
-
Diffusion tensor imaging (DTI) is sensitive to brain microstructural changes. The aims of this DTI study were to map voxelwise the spatial distribution of brain microstructural changes in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and to investigate any correlation between DTI-derived indices and extension of T2 hyperintensity. ⋯ Our results indicate that brain damage in CADASIL is associated with extensive microstructural changes implying impairment of intra- and inter-hemispheric cerebral, thalamocortical, and cerebrocerebellar connections. Severity of microstructural changes correlates with extension of T2 hyperintensity.
-
Averaging multiple repetitions to improve signal-to-noise ratio is common practice in magnetic resonance spectroscopy (MRS). However, temporal variations in scanner B0 due to motion or gradient heating may cause spectra to become misaligned, broadening and distorting peaks and impacting on processing and quantification. We present a comparison using in vivo data of different methods for correcting these errors. ⋯ Frequency correction is an important step in processing MRS data, significantly impacting metabolite quantification, particularly after echo-planar imaging that often occurs with MRS scans in clinical studies. Spectral registration proved most effective at frequency correction.
-
Randomized Controlled Trial
Utilization of Emergent Neuroimaging for Thrombolysis-Eligible Stroke Patients.
Advances in diagnostic imaging of stroke include multimodal techniques such as noninvasive angiography and perfusion imaging. We aimed to characterize trends in neuroimaging utilization among acute stroke patients. Utilization of multimodal imaging for acute stroke in the community has remained largely uncharacterized despite its increased adoption at academic medical centers. ⋯ Among acute stroke patients, noncontrast CT was the most common initial imaging strategy in clinical practice in the 2005-2012 time period, though use of concomitant CTA grew to one-quarter of cases, suggestive of an upward trend.
-
The purpose of this study was to investigate differences in brain cortical thickness of systemic lupus erythematosus (SLE) patients with and without episodic memory impairment and healthy controls. ⋯ Different memory-related cortical regions thinning were found in the episodic memory deficit group when individually compared to the groups of patients without memory impairment and healthy controls.