Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Although high-resolution magnetic resonance imaging (HR-MRI) is considered optimal for the diagnosis of intracranial vertebral artery dissection (IVAD), it is not readily available for all patients with suspected IVAD. The purpose of our study was to determine the factor related to IVAD lesions that are not definitively diagnosed by conventional MRI. ⋯ HR-MRI may be useful for diagnosing IVAD without aneurysmal dilatation or with ipsilesional vertebral hypoplasia.
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Isolated lesions of the medulla oblongata are difficult to diagnose due to their rarity and high biopsy risk. Several individual case reports have been published, but a systematic descriptive study is lacking. Our study has three objectives that 1) provide a differential diagnosis, 2) describe magnetic resonance imaging (MRI) findings, and 3) propose a stepwise MRI-based approach to the isolated lesions of the medulla oblongata in nonstroke patients. ⋯ Neoplasms are the most common cause of isolated medullary lesions in nonstroke patients. Other differential diagnoses include vascular malformations, demyelinating/inflammatory lesions, and infections. A stepwise MRI-based approach can help differentiate between various etiologies.
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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.
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Administration of intravenous tissue plasminogen activator (tPA) in the computed tomography (CT) scanner has been recently implemented at our institution, as a means to decrease door-to-needle time. This change in protocol provided us a unique opportunity to visualize imaging signs of early recanalization. ⋯ Early recanalization of large-vessel occlusion after intravenous thrombolysis results in unique imaging findings.
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To describe the potential role of dynamic contrast-enhanced (DCE) MRI in differentiating carotid space (CS) paraganglioma from schwannoma in the head and neck. ⋯ DCE-MRI could potentially be used to assist differentiating paraganglioma from schwannoma, when diagnosis is difficult on the conventional MR imaging sequences. Simple assessment of semiquantitative parameters suffices to provide supportive information.