Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Neurosurgery makes use of preoperative imaging to visualize pathology, inform surgical planning, and evaluate the safety of selected approaches. The utility of preoperative imaging for neuronavigation, however, is diminished by the well-characterized phenomenon of brain shift, in which the brain deforms intraoperatively as a result of craniotomy, swelling, gravity, tumor resection, cerebrospinal fluid (CSF) drainage, and many other factors. As such, there is a need for updated intraoperative information that accurately reflects intraoperative conditions. ⋯ We begin by evaluating these ultrasound technologies and their relative advantages and disadvantages. We then review three specific applications of these ultrasound technologies to brain tumor resection: (1) intraoperative navigation, (2) assessment of extent of resection, and (3) brain shift monitoring and compensation. We conclude by identifying opportunities for future directions in the development of ultrasound technologies.
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Randomized Controlled Trial Multicenter Study
The Relationship Between Brain MR Spectroscopy and Disability in Multiple Sclerosis: 20-Year Data from the U.S. Glatiramer Acetate Extension Study.
Conventional MRI techniques do not necessarily provide information about multiple sclerosis (MS) disease pathology or progression. Nonconventional MRI techniques, including proton magnetic resonance spectroscopy ((1) H-MRS), are increasingly used to improve the qualitative and quantitative specificity of MR images. This study explores potential correlations between MRI measures of disease and disability progression as measured by the Expanded Disability Status Scale (EDSS), Functional Systems (FS), and ambulation index scores in a unique cohort of MS patients treated with glatiramer acetate that has been closely monitored for over 20 years. ⋯ Among patients with MS receiving long-term glatiramer acetate therapy, consistent effects on disability levels indicated by EDSS and pyramidal FS score thresholds were found for tNAA/tCr concentration ratio and T1 lesion volume.
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Case Reports
Visualization of the Intimal Flap in Intracranial Arterial Dissection Using High-Resolution 3T MRI.
Presence of an intimal flap is a critical imaging finding in diagnosing intracranial artery dissection (ICAD). Recent reports showed that high-resolution magnetic resonance imaging (MRI) was better at identifying intimal flaps as compared with routine MRI techniques used in clinical settings. However, no current standardized sequence for high-resolution MRI without gadolinium enhancement produces images of satisfactory quality with clinically tolerable scanning times. This study evaluated a nonenhanced high-resolution fast spin echo (HR-FSE) MRI sequence for visualizing intimal flaps in patients with ICAD. ⋯ The present method of optimized HR-FSE imaging with a 3T system improved visualization of intimal flaps and should thus be considered for assessing patients with suspected ICAD that cannot be definitively diagnosed by conventional imaging modalities.
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We detected a novel imaging sign, which consists of a specific imaging pattern of diffuse susceptibility effect, delineating the cortical-subcortical junction on high-resolution susceptibility-weighted images (SWIs). We describe magnetic resonance imaging findings in 10 patients with "susceptibility etching" and possible association with their abnormal coagulation profile. ⋯ In this preliminary case series, we describe patients with "susceptibility etching" on SWI who were also found to have profound coagulation impairment. While other comorbities may also contribute to this novel sign, we suggest that a possible etiology may be secondary to microvascular in situ formation of fine thrombi and/or emboli lodged into an area of vascular caliber reduction and maybe related to thrombotic microangiopathy.
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Diffusion tensor imaging (DTI) has previously been used as a biomarker of myelopathy in patients with degenerative cervical cord compression (DCCC). However, many factors may affect the diffusion properties of the spinal cord. This prospective study seeks to identify sources of variability in spinal cord DTI parameters in both DCCC patients and healthy subjects. ⋯ Diffusion parameters of the cervical spinal cord were thus shown to respond significantly to spinal cord compression, but were subject to interaction with several other factors including sex, age, and SCL. These findings may be important to the interpretation of DTI measurements in individual patients.