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Lawrence L. Wald1,2,3 and Clarissa Z. Cooley1,2

1 Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA

2 Harvard Medical School, Boston, MA, USA

3 Division of Health Sciences and Technology, Harvard – Massachusetts Institute of Technology, Cambridge, MA, USA

Portable magnetic resonance imaging (MRI) technology could expand the benefits of MRI to patients who traditionally do not have access. These recipients fall roughly into two segments: patients who live in regions with abundant MRI access but who are difficult to transport into a conventional MRI suite, and those in the large fraction of the world underserved by clinical MRI due to equipment and operational costs.

For the first group, the goal is to influence patient outcomes by bringing the scanner to vulnerable patient populations difficult to bring to a conventional MRI suite. Brain imaging is a prime target due to the supremacy of MR contrast in this important organ, and the time-sensitive need for brain evaluation in many conditions, including stroke, elevated intracranial pressure (ICP) from hemorrhage, edema, hydrocephalus, or neonatal injuries such as hypoxic-ischemic encephalopathy (HIE). Furthermore, MR is intrinsically well suited for repeated scanning scenarios (such as monitoring) if a sufficiently nonobtrusive device is available.

The vast majority of emergency departments (EDs) and intensive care units (ICUs) currently lack MRI scanners. Although these facilities are located in hospitals equipped with MRI suites, it is also not always easy to transport the patient, even within the same building. EDs rely almost exclusively on ultrasound (US) and computed tomography (CT) for tomographic imaging. While the unique imaging capabilities of MRI (e.g. for evaluation of acute stroke) have led some hospitals to install scanners within their ED, this is a rarity, existing in only a small number of large tertiary care centers [1–3]. Even fewer hospitals have an MRI scanner within their ICUs. Additionally, the COVID-19 pandemic has taught us the importance of portable imaging modalities [4], with portable chest X-ray systems by far the most utilized [5], followed by CT [6,7] and US [8]. MR has shown the potential for assessing unique neurological manifestations of COVID-19 not sufficiently evaluated by CT [9] but is little used due to the barriers to transporting these acutely ill and infectious patients. The first-choice modality for patients in such a setting would ideally be brought into the patient’s room, utilized for a point-of-care (POC) scan, wheeled out, and disinfected.

The second group (access in low-income areas) is addressed mainly through cost reduction. Geographical MRI accessibility gaps have been recently reviewed in West Africa [10] and worldwide [11]. The degree to which some regions lag behind worldwide averages for the number of scanners per capita is shocking. For example, 11 African countries have no scanner. However, there is also some indication that low-income countries overspend on high-end medical equipment relative to other infrastructure [12]. Together, this underscores the need to reduce the cost of the MRI equipment if we hope to serve this community. Additionally, economic accessibility gaps are not limited to low-income countries, but also rural areas of middle- to high-income countries where the density of patients is insufficient to support the cost and operation of the scanner [13].