Low-field magnetic resonance imaging (LF-MRI) has recently emerged as a novel approach to extend MRI capability into critical care environments and offers a unique opportunity to support repeated imaging during periods when neurological examination is unreliable or limited.
Abstract
Neurological deterioration is a frequent and clinically significant challenge in patients with acute stroke admitted to neurocritical care units, where timely neuroimaging is essential but access to advanced imaging may be limited by patient instability and logistical constraints. Low-field magnetic resonance imaging (LF-MRI) has recently emerged as a novel approach to extend MRI capability into critical care environments. This topic review synthesizes current evidence on the feasibility, safety, and evolving clinical applications of LF-MRI in neurocritical care stroke. Existing studies demonstrate its utility in diagnostic clarification, longitudinal monitoring of brain injury, and detection of selected secondary complications. Key applications include intracerebral hemorrhage detection and volumetric assessment, quantification of midline shift, ventricular monitoring, evaluation of infarct evolution and cerebral edema, and assessment of unexplained neurological deterioration. Beyond these applications, LF-MRI offers a unique opportunity to support repeated imaging during periods when neurological examination is unreliable or limited. LF-MRI should be viewed as a complementary imaging modality rather than a replacement for computed tomography or conventional high-field MRI. Future advances in sequence development, workflow integration, and rigorously validated artificial intelligence-assisted quantitative tools are expected to further define its role in risk stratification, time-sensitive decision-making, and longitudinal neurocritical care pathways. As access to portable imaging expands, LF-MRI has the potential to reshape neuroimaging strategies in critically ill patients with stroke.
The current clinical evidence base is reviewed, including the role of LF-MRI in supporting stroke-type classification and tissue confirmation, in wake-up and unknown-onset stroke for tissue-based triage, and in post-therapeutic settings to enable serial assessment after thrombolysis or thrombectomy.
A. Sorby-Adams, N. Pintér, Keith W. Muir et al.· Stroke· 0 citations
Low-field and portable MRI show promising diagnostic potential for AIS and TIA, particularly when conventional MRI is unavailable, delayed, or impractical, but current evidence is limited by small, predominantly single-center studies with substantial risk of bias.
Rachana R. Borkar, Sai Dhanush Reddy Jeggari, Kamal Kandel et al.· Brain Science· 0 citations
This review focuses on the current landscape and future direction for low-field magnetic resonance imaging in the prehospital setting, with a discussion of current and upcoming devices, and potential barriers to ambulance integration and how these may be overcome.
James L. Barker, A. Balabanski, Angela Dos Santos et al.· Stroke· 0 citations
BACKGROUND Elective endovascular neurosurgical procedures are increasingly performed in ambulatory neurosurgery centers, enabled by advances in catheter technology, safety of conscious sedation, and refined patient selection. Although complication rates are low, rapid evaluation of postprocedural neurological deficits remains critical. Conventional MRI is often impractical in outpatient or procedural settings, whereas ultra-low-field portable MRI (ULF-pMRI) systems (such as Swoop) allow bedside imaging with favorable diagnostic performance. OBSERVATIONS Two women in their 60s developed acute neurological deficits at an ambulatory neurosurgery center (ANSC) after diagnostic cerebral angiography in one case and elective internal carotid artery flow diversion in the other. In both cases, repeat angiography showed patent vessels. Bedside ULF-pMRI with diffusion-weighted and fluid-attenuated inversion recovery sequences demonstrated no acute infarction or hemorrhage. Symptoms fully resolved with supportive management. The availability of rapid portable MRI helped both patients avoid hospital admission, allowing same-day discharge without recurrent neurological symptoms. LESSONS In these 2 cases, ULF-pMRI demonstrated timely, informative neuroimaging in an ANSC setting. When paired with clinical improvement, bedside MRI safely guided disposition decisions, helped avoid unnecessary transfers, and supported patient safety as outpatient neurointervention expands. https://thejns.org/doi/10.3171/CASE26245
Devan Patel, Vinay Jaikumar, Taysia P T Morioka et al.· Journal of Neurosurgery: Cas...· 0 citations
BACKGROUND
Stroke and transient ischemic attack (TIA) are clinical diagnoses; however, magnetic resonance imaging (MRI) with diffusion weighted imaging (DWI) is frequently used as a supplement in the diagnostic process and may also assist in differentiating stroke from stroke mimics. We aimed to test strengths and weaknesses of applying MRI as first scan in patients with suspected stroke, using clinical diagnoses as a reference.
METHODS
Patients consecutively admitted with suspected stroke to a non-comprehensive stroke emergency medical unit with a concomitant MRI were included. A neuroradiologist and a neurology resident collected imaging and clinical data, respectively. We calculated sensitivity and specificity between clinical diagnosis and radiological findings, and tested associations between bedside characteristics and disagreement in diagnoses.
RESULTS
We included 627 patients (mean age 68 years, 56% female) and found 137 (22%) had ischemic stroke, 102 (16%) TIA, and 5 (0.8%) hemorrhagic strokes at discharge. On the MRI, 155 (25%) had ischemic lesions, 8 (1.3%) hemorrhagic lesions. For all ischemic strokes or TIAs there was 58% sensitivity and 96% specificity with MRI where sensitivity increased to 93% when excluding TIA-patients. Persistent symptoms at admission in the Emergency Department and unilateral motor symptoms associated with DWI-positive stroke/TIA whereas decreased level of consciousness associated with DWI-positive stroke/TIA mimics.
CONCLUSIONS
In non-comprehensive stroke care with an MRI-first approach, MRI is moderately sensitive and highly specific for stroke and TIA, and its performance varies depending on the clinical context.
M. Sagar, C. H. Krag, K. Gandrup et al.· Clinical neurology and neuro...· 0 citations
Magnetic resonance imaging (MRI) has become the gold standard for evaluating brain injury and development in newborn infants, providing structural, metabolic, and functional information without ionizing radiation. This review comprehensively examines the principal MRI modalities used in current neonatal neuroimaging for a novice/intermediate-level reader—including conventional T1- and T2-weighted imaging, diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping, diffusion tensor imaging (DTI), magnetic resonance spectroscopy (MRS), susceptibility-weighted imaging (SWI), volumetric analysis, arterial spin labeling (ASL), and functional connectivity MRI—with particular attention to their applications in preterm and term populations. Additionally, validated MRI scoring systems for quantifying brain injury severity and predicting neurodevelopmental outcomes are reviewed and summarized. Understanding the technical principles, clinical applications, and limitations of these modalities is essential for optimal interpretation of neonatal brain MRI, and for advancing prognostication and therapeutic decision-making in this vulnerable population.
