Detecting acute ischemic lesions using mobile,low-field MRI in TIA and minor stroke in the emergency room

Abstract

Background:

Using mobile low-field magnetic resonance imaging (MRI) in the emergency department to detect cerebral infarction(s) in patients with minor ischemic stroke (MIS) and transient ischemic attack (TIA) has not yet been thoroughly reported.

Aim:

We aimed to evaluate the performance of mobile low-field (0.23T) MRI in detecting acute ischemic infarction in MIS or TIA patients within 72 h of symptom onset and compare it to computed tomography (CT) in those scanned within 24 h. We also aimed to analyze predictors of DWI-positive lesions on mobile MRI.

Methods:

This prospective observational cohort consecutively included patients with MIS (National Institutes of Health Stroke Scale (NIHSS) ⩽ 5) or TIA who underwent mobile low-field MRI within 72 h of symptom onset in the emergency department of a tertiary general hospital. The MRI protocol included localizer, axial T1-weighted fluid-attenuated inversion recovery (FLAIR), axial T2-weighted FLAIR, axial T2-weighted fast spin-echo, hematoma-enhanced inversion recovery (HEIR), and diffusion-weighted imaging (DWI) with apparent diffusion coefficient sequences. The total acquisition time is 10 min 28 s. Two raters, blinded to clinical information and CT findings, interpreted the MRI images for acute infarction. Multivariable logistic regression identified predictors of DWI positivity. The primary outcome was restricted diffusion (acute infarction) on the brain low-field MRI scan. We analyzed patients who underwent head CT scan within 24 h of low-field MRI to compare the detection rates of acute infarction between low-field MRI and head CT.

Results:

A total of 974 patients (564 men and 410 women; mean (standard deviation, SD) age, 61.3 (14.9) were enrolled. New ischemic lesions were detected by low-field MRI on the DWI sequence in 37.4% (338 in 974) of patients. Among them, 304 underwent head CT within 24 h of the low-field MRI scan; CT identified new ischemic lesions in only 122 (40.1%) of these. Higher NIHSS score (hazard ratio, 1.36 (95% confidence interval (CI), 1.21–1.54); p < 0.01), longer onset to imaging time (hazard ratio, 1.33 (95% CI, 1.10–1.63); p < 0.01), aphasia (hazard ratio, 2.24 (95% CI, 1.36–3.71); p < 0.01), and hemiplegia (hazard ratio, 2.50 (95% CI, 1.76–3.55); p < 0.01) were independently associated with DWI positivity on mobile low-field MRI. Female sex (hazard ratio, 0.57 (95% CI, 0.42–0.79); p < 0.01) and non-focal symptoms were negatively associated with DWI positivity.

Conclusion:

Mobile low-field MRI provides a safe, efficient, and accessible imaging solution for MIS and TIA evaluation in emergency settings and detects more acute infarctions than non-contrast head CT. Higher NIHSS score, longer onset to imaging time and focal clinical features were independently associated with DWI positivity.

Graphical abstract

Keywords

Mobile low-field MRI minor ischemic stroke transient ischemic attack acute ischemic lesion diffusion-weighted imaging

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References

Rothwell

Warlow

CP.

Timing of TIAs preceding stroke: time window for prevention is very short. Neurology 2005; 64: 817–820.

von Weitzel-Mudersbach

Andersen

Hundborg

Johnsen

. Transient ischemic attack and minor stroke are the most common manifestations of acute cerebrovascular disease: a prospective, population-based study–the Aarhus TIA study. Neuroepidemiology 2013; 40: 50–55.

Johnston

Rothwell

Nguyen-Huynh

, et al Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet 2007; 369: 283–292.

Jeerakathil

AYX

Choi

PMC

, et al Effects of a province-wide triaging system for TIA: the ASPIRE intervention. Neurology 2023; 100: e2093–e2102.

Diener

Frank

Stroke: stroke prevention–time to say goodbye to the ABCD2 score?

Nat Rev Neurol 2015; 11: 552–553.

Jing

Suo

Wang

, et al Imaging parameters predict recurrence after transient ischemic attack or minor stroke stratified by ABCD(2) score. Stroke 2021; 52: 2007–2015.

Kleindorfer

Towfighi

Chaturvedi

, et al 2021 guideline for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline from the American heart association/American stroke association. Stroke 2021; 52: e364–e467.

Jing

Xie

Johnston

, et al Genotype-guided dual antiplatelet use for transient ischemic attack and minor stroke by imaging status: subgroup analysis of the CHANCE-2 trial. Ann Neurol 2023; 93: 783–792.

Gao

Chen

Pan

, et al Dual antiplatelet treatment up to 72 hours after ischemic stroke. N Engl J Med 2023; 389: 2413–2424.

10.

Rapillo

Dunet

Pistocchi

, et al Moving from CT to MRI paradigm in acute ischemic stroke: feasibility, effects on stroke diagnosis and long-term outcomes. Stroke 2024; 55: 1329–1338.

11.

Liu

Leong

ATL

Zhao

, et al A low-cost and shielding-free ultra-low-field brain MRI scanner. Nat Commun 2021; 12: 7238.

12.

Yuen

Prabhat

Mazurek

, et al Portable, low-field magnetic resonance imaging enables highly accessible and dynamic bedside evaluation of ischemic stroke. Sci Adv 2022; 8: eabm3952.

13.

National Medical Products Administration. Basic information of domestic medical device (registration)—“National medical device approval no. 20223060289..” www.nmpa.gov.cn/datasearch/search-info.html?nmpa=aWQ9ZTExOTFmNmJiODYxMjg5ZjU0OTQwYWQyMjE1ODNiYzUmaXRlbUlkPWZmODA4MDgxODNjYWQ3NTAwMTgzY2I2NmZlNjkwMjg1 (2022, accessed 25 October 2024).

14.

Xiong

Zhao

, et al Clinical characteristics and in-hospital outcomes of varying definitions of minor stroke: from a large-scale nation-wide longitudinal registry. Stroke 2021; 52: 1253–1258.

15.

Jing

Xie

Leng

, et al Chinese stroke association guidelines on emergency stroke unit. Stroke Vasc Neurol 2024; 9: 741–745.

16.

Amarenco

Lavallee

Labreuche

, et al One-year risk of stroke after transient ischemic attack or minor stroke. N Engl J Med 2016; 374: 1533–1542.

17.

Tanaka

Coutts

Joundi

, et al Presenting symptoms and diffusion-weighted MRI positivity by time after transient neurologic events. Neurology. 2024; 102: e207846.

18.

Al-Khaled

Matthis

Münte

Eggers

The incidence and clinical predictors of acute infarction in patients with transient ischemic attack using MRI including DWI. Neuroradiology 2013; 55: 157–163.

19.

Coutts

Moreau

Asdaghi

, et al Rate and prognosis of brain ischemia in patients with lower-risk transient or persistent minor neurologic events. JAMA Neurol 2019; 76: 1439–1445.

20.

Al-Khaled

Eggers

MRI findings and stroke risk in TIA patients with different symptom durations. Neurology 2013; 80: 1920–1926.

21.

Lodha

Patel

Harrell

, et al Motor impairments in transient ischemic attack increase the odds of a positive diffusion-weighted imaging: a meta-analysis. Restor Neurol Neurosci 2019; 37: 509–521.

22.

Kerber

Brown

Lisabeth

Smith

Morgenstern

LB.

Stroke among patients with dizziness, vertigo, and imbalance in the emergency department: a population-based study. Stroke 2006; 37: 2484–2487.

23.

Bonkhoff

Schirmer

Bretzner

, et al Outcome after acute ischemic stroke is linked to sex-specific lesion patterns. Nat Commun 2021; 12: 3289.

24.

Pohl

Hesszenberger

Kapus

, et al Ischemic stroke mimics: a comprehensive review. J Clin Neurosci 2021; 93: 174–182.

25.

Chang

Kim

Chung

Yum

Hong

Han

MK.

Hospital-based prospective registration of acute transient ischemic attack and noncerebrovascular events in Korea. J Stroke Cerebrovasc Dis 2015; 24: 1803–1810.

26.

Amin

Madsen

Bravata

, et al Diagnosis, workup, risk reduction of transient ischemic attack in the emergency department setting: a scientific statement from the American heart association. Stroke 2023; 54: e109–e121.

27.

Chalela

Kidwell

Nentwich

, et al Magnetic resonance imaging and computed tomography in emergency assessment of patients with suspected acute stroke: a prospective comparison. Lancet 2007; 369: 293–298.

28.

Suo

Xie

Zhang

, et al Mobile 0.23 T MRI detects cerebral infarction in patients with minor ischemic stroke or TIA. Stroke. 2024; 55: e249–e251.

29.

Yaghi

Herber

Boehme

, et al The association between diffusion MRI-defined infarct volume and NIHSS score in patients with minor acute stroke. J Neuroimaging 2017; 27: 388–391.

30.

Khatri

Kleindorfer

Devlin

, et al Effect of alteplase vs aspirin on functional outcome for patients with acute ischemic stroke and minor nondisabling neurologic deficits: the PRISMS randomized clinical trial. JAMA 2018; 320: 156–166.