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Background: Neuroimaging is essential for detecting spontaneous, nontraumatic intracerebral hemorrhage (ICH). Recent data suggest ICH can be characterized using low-field magnetic resonance imaging (MRI). Our primary objective was to investigate the sensitivity and specificity of ICH on a 0.064T portable MRI (pMRI) scanner using a methodology that provided clinical information to inform rater interpretations. As a secondary aim, we investigated whether the incorporation of a deep learning (DL) reconstruction algorithm affected ICH detection., Methods: The pMRI device was deployed at Yale New Haven Hospital to examine patients presenting with stroke symptoms from October 26, 2020 to February 21, 2022. Three raters independently evaluated pMRI examinations. Raters were provided the images alongside the patient's clinical information to simulate real-world context of use. Ground truth was the closest conventional computed tomography or 1.5/3T MRI. Sensitivity and specificity results were grouped by DL and non-DL software to investigate the effects of software advances., Results: A total of 189 exams (38 ICH, 89 acute ischemic stroke, 8 subarachnoid hemorrhage, 3 primary intraventricular hemorrhage, 51 no intracranial abnormality) were evaluated. Exams were correctly classified as positive or negative for ICH in 185 of 189 cases (97.9% overall accuracy). ICH was correctly detected in 35 of 38 cases (92.1% sensitivity). Ischemic stroke and no intracranial abnormality cases were correctly identified as blood-negative in 139 of 140 cases (99.3% specificity). Non-DL scans had a sensitivity and specificity for ICH of 77.8% and 97.1%, respectively. DL scans had a sensitivity and specificity for ICH of 96.6% and 99.3%, respectively., Conclusions: These results demonstrate improvements in ICH detection accuracy on pMRI that may be attributed to the integration of clinical information in rater review and the incorporation of a DL-based algorithm. The use of pMRI holds promise in providing diagnostic neuroimaging for patients with ICH., Competing Interests: Disclosures Dr Sheth is the principal investigator. Dr Sheth reports compensation from CSL Behring for consultant services; grants from BARD; compensation from Astrocyte for consultant services; compensation from Rhaeos for consultant services; compensation from Certus for consultant services; grants from Novartis; a patent pending for Stroke wearables licensed to Alva Health; compensation from Cerevasc for consultant services; compensation from ZOLL Medical Corporation for data and safety monitoring services; grants from Hyperfine; employment by Yale School of Medicine; compensation from Sense for data and safety monitoring services; grants from Hyperfine to other; and grants from Biogen. Dr Kimberly reports grants from NControl Therapeutics; compensation from Astrocyte Pharmaceuticals for consultant services; compensation from Acasti Pharmaceuticals for consultant services; grants from Hyperfine Research Inc; a patent pending for No. 16/486 687, Methods and Compositions for Treating a Brain Injury. licensed to NControl Therapeutics; grants from Biogen; stock holdings in Woolsey Pharmaceuticals; and compensation from NControl Therapeutics for consultant services. Dr de Havenon reports compensation from Novo Nordisk for consultant services; compensation from Integra for consultant services; grants from National Institutes of Health (NIH); stock options in Certus; and stock options in TitinKM. Dr Rosen reports grants from American Heart Association (AHA), Advanced Research Projects Agency–Energy (ARPA-E), Department of Energy (DOE), and the NIH. Dr Rosen is on the scientific advisory board of ABQMR, Synex Medical, Inc, Nanalysis, Inc, O2M Technologies, Inc, Quantum Catalyzer, Inc, and Lincoln Agritech LTD. Dr Rosen is a Founder and equity holder of Hyperfine, Vizma Life Sciences, Intact Data Services, and Q4ML. He acknowledges the support of the Kiyomi and Ed Baird Research Scholar award. Dr Matouk reports compensation from Silk Road Medical, Inc, for consultant services; compensation from MicroVention, Inc, for consultant services; and compensation from Penumbra, Inc, for consultant services. Dr Falcone reports grants from AHA and grants from National Institutes of Health. Dr Sorby-Adams reports grants from Australian-American Fulbright Commission and grants from AHA. The other authors report no conflicts.

Background White matter hyperintensity (WMH) on magnetic resonance imaging (MRI) of the brain is associated with vascular cognitive impairment, cardiovascular disease, and stroke. We hypothesized that portable magnetic resonance imaging (pMRI) could successfully identify WMHs and facilitate doing so in an unconventional setting. Methods and Results In a retrospective cohort of patients with both a conventional 1.5 Tesla MRI and pMRI, we report Cohen's kappa (κ) to measure agreement for detection of moderate to severe WMH (Fazekas ≥2). In a subsequent prospective observational study, we enrolled adult patients with a vascular risk factor being evaluated in the emergency department for a nonstroke complaint and measured WMH using pMRI. In the retrospective cohort, we included 33 patients, identifying 16 (49.5%) with WMH on conventional MRI. Between 2 raters evaluating pMRI, the interrater agreement on WMH was strong (κ=0.81), and between 1 rater for conventional MRI and the 2 raters for pMRI, intermodality agreement was moderate (κ=0.66, 0.60). In the prospective cohort we enrolled 91 individuals (mean age, 62.6 years; 53.9% men; 73.6% with hypertension), of which 58.2% had WMHs on pMRI. Among 37 Black and Hispanic individuals, the Area Deprivation Index was higher (versus White, 51.8±12.9 versus 37.9±11.9; P <0.001). Among 81 individuals who did not have a standard-of-care MRI in the preceding year, we identified WMHs in 43 of 81 (53.1%). Conclusions Portable, low-field imaging could be useful for identifying moderate to severe WMHs. These preliminary results introduce a novel role for pMRI outside of acute care and the potential role for pMRI to reduce disparities in neuroimaging.

In the 20th century, the advent of neuroimaging dramatically altered the field of neurologic care. However, despite iterative advances since the invention of CT and MRI, little progress has been made to bring MR neuroimaging to the point of care. Recently, the emergence of a low-field (<1 T) portable MRI (pMRI) is setting the stage to revolutionize the landscape of accessible neuroimaging. Users can transport the pMRI into a variety of locations, using a standard 110-220 V wall outlet. In this article, we discuss current applications for pMRI, including in the acute and critical care settings, the barriers to broad implementation, and future opportunities., (© 2023 American Academy of Neurology.)