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
Highlights What are the main findings? Portable MRI enabled safe bedside imaging in emergency and intensive care settings, although detection of very small (<5–6 mm) ischemic lesions remained less reliable than conventional high-field MRI. Diagnostic performance was influenced by lesion size and field strength, with low-field MRI reliably detecting most clinically relevant infarcts. What are the implications of the main findings? Low-field and portable MRI can expand timely access to stroke imaging where conventional MRI is unavailable, delayed, or unsafe, particularly in emergency departments, ICUs, and resource-limited settings. Continued improvements in hardware, imaging sequences, and multicenter validation studies are needed before low-field MRI can be adopted as a routine alternative to conventional high-field MRI for acute stroke evaluation. Abstract Background: Magnetic resonance imaging (MRI) has a central role in acute ischemic stroke (AIS) and transient ischemic attack (TIA) diagnosis; however, conventional high-field MRI remains limited by infrastructure requirements, patient transport, and restricted accessibility. Low-field and portable MRI systems have emerged as potential solutions for point-of-care neuroimaging in emergency, intensive care, and resource-limited settings. Methods: A systematic review was conducted according to PRISMA 2020 guidelines. PubMed, Scopus, Web of Science, and Cochrane Library databases were searched from inception through May 2026. Studies evaluating low-field or portable MRI systems (≤0.55 T) in adults with AIS, TIA, sub-acute ischemic stroke, or suspected stroke were included. Diagnostic accuracy, feasibility, safety, workflow, and clinical utility outcomes were extracted. Risk of bias was assessed using QUADAS-2. Results: Eleven studies encompassing portable and low-field MRI platforms ranging from 0.064 T to 0.55 T were included. Portable MRI demonstrated feasibility in bedside ICU and emergency department settings without major device-related adverse events. Diagnostic performance varied by field strength, lesion size, and imaging protocol. Conclusions: Low-field and portable MRI show promising diagnostic potential for AIS and TIA, particularly when conventional MRI is unavailable, delayed, or impractical. However, current evidence is limited by small, predominantly single-center studies with substantial risk of bias, and further prospective multicenter validation is required before these technologies can be incorporated into routine clinical decision-making.
Rachana R. Borkar, Sai Dhanush Reddy Jeggari, Kamal Kandel et al.· Brain Science· 0 citations
Stroke is a leading cause of morbidity and mortality globally. Prehospital stroke care is a rapidly growing field to improve stroke outcomes. Methods to assess patients in the prehospital setting include clinical scales and portable neuroimaging that are usually restricted to mobile stroke unit computed tomography scanners, which are not widely available. Lightweight low-field magnetic resonance imaging devices at the <0.1T range offer an opportunity for portable lightweight imaging for the prehospital setting, with the advantage of greater tissue assessment to diagnose stroke. 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. Low-field magnetic resonance imaging provides an exciting opportunity for portable and safe imaging for the prehospital setting for the early diagnosis of stroke and the initiation of triage and treatment. These devices have the potential to be much more widely available and accessible than the current prehospital assessment model of mobile stroke units and provide additional detail for treatment decisions compared with non-imaging-supported telehealth prehospital assessments.
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.