The Brain Tumor Segmentation - Metastases (BraTS-METS) Challenge 2023: Brain Metastasis Segmentation on Pre-treatment MRI.

The translation of AI-generated brain metastases (BM) segmentation into clinical practice relies heavily on diverse, high-quality annotated medical imaging datasets. The BraTS-METS 2023 challenge has gained momentum for testing and benchmarking algorithms using rigorously annotated internationally compiled real-world datasets. This study presents the results of the segmentation challenge and characterizes the challenging cases that impacted the performance of the winning algorithms.

Leptomeningeal Enhancement on 3D-FLAIR MRI in Multiple Sclerosis: Systematic Observations in Clinical Practice.

Background And Purpose: Meningeal inflammation is implicated in cortical demyelination and disability progression in multiple sclerosis (MS). Gadolinium (Gd)-enhanced 3-dimensional (3D) FLAIR (fluid-attenuated inversion recovery) magnetic resonance imaging (MRI) can identify leptomeningeal enhancement (LME) in MS. Further characterization is needed to determine if LME is an imaging biomarker for meningeal inflammation.

Design and fabrication of prototype piezoelectric adjustable X-ray mirrors.

Lynx, a next generation X-ray observatory concept currently under study, requires lightweight, high spatial resolution X-ray mirrors. Here we detail the development and fabrication of one of the candidate technologies for Lynx, piezoelectric adjustable X-ray optics. These X-ray mirrors are thin glass shell mirrors with Cr/Ir X-ray reflective coatings on the mirror side and piezoelectric thin film actuators on the actuator side.

Indirect measurement of regional axon diameter in excised mouse spinal cord with q-space imaging: simulation and experimental studies.

Q-space imaging (QSI), a diffusion MRI technique, can provide quantitative tissue architecture information at cellular dimensions not amenable by conventional diffusion MRI. By exploiting regularities in molecular diffusion barriers, QSI can estimate the average barrier spacing such as the mean axon diameter in white matter (WM). In this work, we performed ex vivo QSI on cervical spinal cord sections from healthy C57BL/6 mice at 400 MHz using a custom-designed uniaxial 50T/m gradient probe delivering a 0.

Hemostatic and neuroprotective effects of human recombinant activated factor VII therapy after traumatic brain injury in pigs.

Human recombinant activated factor-VII (rFVIIa) has been used successfully in the treatment of spontaneous intracerebral hemorrhage. In addition, there is increasing interest in its use to treat uncontrolled bleeding of other origins, including trauma. The aim of this study was to evaluate the safety and potential effectiveness of rFVIIa to mitigate bleeding using a clinically relevant model of traumatic brain injury (TBI) in the pig.

The impact of methylprednisolone on lesion severity following spinal cord injury.

Study Design: Retrospective study comparing spinal cord injury (SCI) lesion characteristics in methylprednisolone (MPS) treated versus untreated patients as demonstrated by magnetic resonance (MR) imaging.

Objective: Determine if the administration of MPS immediately following SCI affects lesion severity.

Summary Of Background Data: The administration of MPS in the setting of acute SCI has become controversial.

Bilateral aortic origins of the vertebral arteries with right vertebral artery arising distal to left subclavian artery: case report.

Background: Bilateral aortic origins of the vertebral arteries are a rare anatomic variant, with fewer than 20 cases reported in the literature. This particular variant has only been reported twice.

Case Description: A 35-year-old woman presented to the emergency department after trauma to the head and a witnessed convulsion.

In vivo DTI evaluation of white matter tracts in rat spinal cord.

Purpose: To determine whether differences in specific spinal cord white matter (WM) tracts can be detected with in vivo DTI.

Materials And Methods: In vivo DTI was performed on six rats at the lower thoracic region using a 4.7T magnet.

Spinal cord diffusion tensor imaging and fiber tracking can identify white matter tract disruption and glial scar orientation following lateral funiculotomy.

Diffusion tensor magnetic resonance imaging (DTI) provides data concerning water diffusion in the spinal cord, from which white matter tracts may be inferred, and connectivity between spinal cord segments may be determined. We evaluated this potential application by imaging spinal cords from normal adult rats and rats that received cervical lateral funiculotomies, disrupting the rubrospinal tract (RST). Vitrogen and fibroblasts were transplanted into the surgical lesion at time of injury in order to fill the cavity.

Ex vivo evaluation of ADC values within spinal cord white matter tracts.

Background And Purpose: Our purpose was to evaluate the effect of fixative on apparent diffusion coefficient (ADC) values and anisotropy within spinal cord white matter. As glutaraldehyde (GL) better preserves axonal ultrastructure as compared with paraformaldehyde (PF), we hypothesize that spinal cord white matter fixed with GL will have increased anisotropic water diffusion as compared with specimens fixed with PF.

Methods: Eleven rats were perfusion-fixed with either 4% PF or a combination of 2.

Apparent diffusion coefficients in spinal cord transplants and surrounding white matter correlate with degree of axonal dieback after injury in rats.

Background And Purpose: Abnormal apparent diffusion coefficient (ADC) values in injured spinal cord white matter and fibroblast transplants have been shown to correspond with qualitative histologic findings of axonal loss or regeneration. We proposed that ADC values would correlate with quantitative axonal tracing in the transected rubrospinal tract (RST).

Methods: Eleven rats received right-sided lateral funiculus lesions at C3-4 (disrupting the RST) and transplantation of fibroblasts that were unmodified or modified to secrete brain-derived neurotrophic factor (BDNF).

MRI diffusion coefficients in spinal cord correlate with axon morphometry.

Following spinal cord injury, diffusion MRI (DWI) has been shown to detect injury and functionally significant neuroprotection following treatment that otherwise would go undetected with conventional MRI. The underlying histologic correlates to directional apparent diffusion coefficients (ADC) obtained with DWI have not been determined, however, and we address this issue by directly correlating ADC values with corresponding axon morphometry in the normal rat cervical spinal cord. ADC values transverse (perpendicular) and longitudinal (parallel) to axons both correlate with axon counts, however each directional ADC reflects distinct histologic parameters.

Assessment of axonal fiber tract architecture in excised rat spinal cord by localized NMR q-space imaging: simulations and experimental studies.

NMR q-space imaging is a method designed to obtain information from porous materials where diffusion-diffraction phenomena were observed from which pore size was derived. Recently, the technique has been applied to the study of biological structures as well. Although diffusive diffraction has so far not been observed in multicellular systems, displacement profiles have been used with some success as a means to estimate structure size.

Diffusion-weighted MRI and the evaluation of spinal cord axonal integrity following injury and treatment.

Diffusion-based magnetic resonance imaging (MRI) (DWI) has been shown experimentally to detect both injury and functionally significant neuroprotection of injured spinal cord white matter that would otherwise go undetected with conventional MRI techniques. The diffusion of water in the central nervous system (CNS) is thought to be affected by both its location (intracellular or extracellular), and by diffusion barriers formed by cell membranes and myelin sheaths. There is, however, controversy concerning how to obtain, interpret, and present DWI data.

Distinguishing ischemic stroke from the stroke-like lesions of MELAS using apparent diffusion coefficient mapping.

We report two patients with migraine, acute visual field defects and other neurological symptoms who were found to have high T(2) signal and FLAIR abnormalities on brain MRI in temporal and parieto-occipital regions. In these patients, the apparent diffusion coefficient (ADC) of their lesions was increased, distinguishing these lesions from those of ischemic stroke. Both were ultimately diagnosed with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS).

Ex vivo MR determined apparent diffusion coefficients correlate with motor recovery mediated by intraspinal transplants of fibroblasts genetically modified to express BDNF.

The purpose of this study was to determine whether apparent diffusion coefficients (ADCs) in ex vivo spinal cord white matter, calculated from diffusion weighted MR (DWI) images, correlate with axonal growth and behavioral recovery following subtotal hemisection and transplantation of fibroblasts genetically modified to express brain derived neurotrophic factor (BDNF). These genetically modified fibroblasts have been shown to promote axonal growth, diminish retrograde degenerative changes in axotomized Red nucleus neurons, and are associated with behavioral recovery. Since changes in ADC appear to reflect damage to axons and myelin sheaths, which conventional MR techniques do not identify, partial repair mediated by BDNF-secreting fibroblasts should be detected with ADC measures.

Complete regression of intracranial arteriovenous malformations.

Background: Spontaneous and complete regression of intracranial arteriovenous malformations (AVMs) is a rare occurrence, with only 59 angiographically proven cases reported in the English literature. We present three new cases and perform a literature review to determine possible mechanisms underlying this unusual phenomenon.

Methods: Three patients with angiographically proven AVMs demonstrated complete obliteration of the AVM on follow-up angiography.

Vertebrobasilar thrombolysis with intravenous tirofiban: case report.

The use of thrombolytic agents in the setting of established cerebral infarction is limited by concerns for hemorrhagic transformation. Novel thrombolytic approaches, which have received minimal consideration, may be associated with lower risks of hemorrhage. We illustrate vertebrobasilar thrombolysis with intravenous tirofiban, a selective platelet glycoprotein IIb/IIIa receptor antagonist, and discuss the potential thrombolytic properties of this class of antithrombotics.

Diffusion-weighted imaging of the spinal cord.

Spinal cord DWI may be useful in providing information not available with conventional MR imaging. More work, however, is required to explain what the qualitative and quantitative results actually represent. Computer simulations and detailed radiologic-histologic correlations will therefore be necessary.