The Swoop® System
Publications
DWI-FLAIR Mismatch Detection Using Portable Low-Field MRI
Follow-up Stroke
Study: Study using a 0.064-T portable MRI to obtain bedside neuroimaging for 50 patients withconfirmed ischemic stroke, validating the modality against conventional high-field MRI for bothlesion detection and stroke-volume quantification across cortical, subcortical and cerebellarterritories.
Key Findings: Low-field pMRI detected infarcts in 45 of 50 patients (90%), capturing lesions as small as 4 mm,which appeared as hyperintense regions on T2-weighted, FLAIR and diffusion-weightedsequences. Stroke-volume measurements were consistent across pMRI sequences and betweenlow-field pMRI and conventional high-field MRI, and correlated significantly with stroke severityand functional outcome at discharge.
Hydrocephalus
Portable Bedside Low-field MRI for Assessment of Ventricular Size (2025)
Study: Retrospective study at a single tertiary hospital evaluating the intermodality reliability of 64 mTportable MRI versus conventional CT or MRI for assessing ventricular size and hydrocephalus. Allpatients who underwent point-of-care pMRI between March 2022 and January 2024 with aconventional scan within 24 hours were included; two raters independently scored pMRI forhydrocephalus while blinded to the conventional study.
Key Findings: Among 56 patients, hydrocephalus was identified in 21% on pMRI and 23% on conventionalimaging. Interrater agreement on pMRI was almost perfect for bifrontal diameter (ICC 0.94) andEvans index (ICC 0.92). Intermodality agreement between pMRI and conventional imaging waslikewise near-perfect for bifrontal diameter (ICC 0.94) and Evans index (ICC 0.95).
Study: Single-blind prospective feasibility study across three tertiary pediatric centres assessing ultra-low-field portable MRI as a supplementary tool — rather than a stand-alone modality — fordetermining ventricular caliber and radiographic features of hydrocephalus. Participants withhydrocephalus or ventriculomegaly were consecutively recruited from neurosurgery andneurology clinics and the emergency department and scanned with standardized protocols.
Key Findings: Across 153 patients (mean age 9.6 years; most common etiologies posthemorrhagic,myelomeningocele and aqueductal stenosis), Bland-Altman plots showed near-congruentagreement between pMRI and standard of care for the Evans index and frontal–occipital hornratio (FOHR). Lin’s concordance correlation coefficient indicated substantial agreement for boththe Evans index (0.922) and FOHR (0.942).
Case Report: Ultralow-field portable MRI improves the diagnosis of congenital hydrocephalus (2025)
Study: Case report from University Hospital Bonn presenting two newborns with congenitalhydrocephalus who underwent ultra-low-field (ULF) portable MRI to investigate the underlyingetiology. Investigation of congenital hydrocephalus should include MRI to detect posterior-fossapathology, yet conventional MRI is frequently unavailable to affected infants — particularly inthe countries with the highest prevalence.
Key Findings: ULF scanning at the bedside revealed a tumor of the posterior fossa (fossa cranii posterior) asthe cause of hydrocephalus in the newborns, demonstrating that the modality can detect andcharacterize brain tumors as well as metastases. In both cases the scan provided diagnosticinformation that directly informed clinical understanding of the infant’s condition.
Midline Shift
Bedside detection of intracranial midline shift using portable magnetic resonance imaging (2022)
Study: Observational study using 0.064-T portable MRI in 102 stroke patients (48 ischemic stroke, 54intracranial hemorrhage) admitted to the neuroscience ICU at Yale New Haven Hospital. Bothdichotomous (present/absent) and continuous midline-shift (MLS) measurements were obtainedon pMRI and on locally available standard-of-care CT or MRI, and related to functional outcomeon the modified Rankin Scale.
Key Findings: There was significant concordance between pMRI and standard-of-care measurements(dichotomous κ=0.87; continuous ICC=0.94), with pMRI identifying MLS at 0.93 sensitivity and0.96 specificity. pMRI-based MLS independently predicted poor discharge outcome (adjusted OR7.98 for the dichotomous measure), recapitulating the well-established link between mass effectand prognosis.
NICU
Application and Acceptance of Bedside MRI in the NICU Setting (2025)
Study: Prospective study at University Hospital Bonn assessing the applicability, safety and stress ofultra-low-field (ULF) MRI in the neonatal ICU. Investigators measured heart rate, oxygensaturation and blood pressure for both the scanned neonate and neighbouring patients, andused questionnaires to capture stress reported by physicians, nurses and parents and any effecton care and parent–child interaction.
Key Findings: No significant differences were found in the physiological measures of scanned versusneighbouring neonates, and neither medical care nor parent–child interaction was affected bythe scan. Imaging could be performed at the bedside during natural sleep and required fewerresources than high-field MRI, with no disturbance to surrounding patients.
Study: Multi-center retrospective analysis of every ICU neuroimaging requisition placed in 2021 at twoCanadian centres — Kingston Health Sciences Centre and St. Michael’s Hospital, Toronto. Theauthors defined clinical indications suited to portable MRI and estimated how many ICU patientscould be diverted to pMRI and the fixed-scanner time this would free.
Key Findings: Combined across both sites, 24.6% of fixed-MRI and 21.0% of fixed-CT non-contrast ICU scanswere eligible for pMRI. Diverting these patients would free roughly 9,000 minutes of MRI and25,140 minutes of CT annually — enough capacity for about 300 additional outpatient MRI and1,676 additional outpatient CT examinations each year.
Bedside Detection of Intracranial Midline Shift using Portable Magnetic Resonance Imaging (2022)
Study: Observational study using 0.064-T portable MRI in 102 stroke patients (48 ischemic stroke, 54intracranial hemorrhage) admitted to the neuroscience ICU at Yale New Haven Hospital. Bothdichotomous (present/absent) and continuous midline-shift (MLS) measurements were obtainedon pMRI and on locally available standard-of-care CT or MRI, and related to functional outcomeon the modified Rankin Scale.
Key Findings: There was significant concordance between pMRI and standard-of-care measurements(dichotomous κ=0.87; continuous ICC=0.94), with pMRI identifying MLS at 0.93 sensitivity and0.96 specificity. pMRI-based MLS independently predicted poor discharge outcome (adjusted OR7.98 for the dichotomous measure), recapitulating the well-established link between mass effectand prognosis.
Study: Prospective study across two hospitals demonstrating bedside deployment of a low-field (0.064-T) portable MRI in critically ill patients with intracerebral hemorrhage (ICH). The datasetcomprised 144 exams on 94 patients — 56 with ICH, 48 with acute ischemic stroke and 40healthy controls — with images reviewed by multiple blinded raters of varying experience to testgeneralizability.
Key Findings: The study established the sensitivity and specificity of ICH detection and the accuracy of ICHlocalization on pMRI. pMRI-derived ICH volume was associated with both stroke severity andpatient outcome — mirroring the well-known prognostic value of ICH volume — and the bedsideworkflow cut the time to prepare, scan and return the patient by more than 50% (67 to 30minutes).
Study: Single-center retrospective analysis combined with a literature review quantifying CT-scanexposure in children with ventriculoperitoneal (VP) shunts, who undergo repeated head CTwhenever shunt dysfunction is suspected. Hospital coding data were cross-referenced withelectronic records and radiology databases to estimate cumulative radiation exposure across thecohort.
Key Findings: Across 152 children (mean 5.4 years with a shunt in situ), an average of 3.33 CT scans wereperformed per child — 0.65 CTs per shunt-year, equating to roughly 1.31 mSv per child pershunt-year. The accompanying review reinforces the risk: two-to-three head CTs have beenassociated with a tripling of brain-tumor risk, and a single childhood head CT with a ~2.4-foldincrease.
NICU-Intracerebral Hemorrhage
Study: Study investigating the sensitivity and specificity of intracerebral hemorrhage (ICH) detection ona 0.064-T portable MRI using a methodology that supplied raters with relevant clinicalinformation, with a secondary aim testing a deep-learning (DL) reconstruction algorithm. Threeboard-certified raters independently evaluated 189 pMRI exams from 177 patients presenting tothe ICU or ED with stroke symptoms, against the closest conventional CT or 1.5/3T MRI as groundtruth.
Key Findings: Exams were correctly classified for ICH in 185 of 189 cases (97.9% overall accuracy), with 92.1%sensitivity and 99.3% specificity. The deep-learning reconstruction sharply improvedperformance: sensitivity rose from 77.8% (non-DL) to 96.6% and specificity from 97.1% to 99.3%.pMRI exams followed conventional imaging by an average of just 17.5 minutes.
NICU – Patients Who Can’t Be Transported
Portable Magnetic Resonance Imaging for ICU Patients (2020)
Study: Prospective, non-randomized, observational study at a single academic medical center using a0.064-T, self-shielding portable MRI in ventilated ICU patients. Nineteen patients with laboratory-confirmed COVID-19 were imaged if they had unexplained encephalopathy or coma, seizures, afocal neurologic deficit, or an abnormal head CT; all scans were performed in the patient’s own ICU room.
Key Findings: Twenty scans were acquired across seven ICUs with no adverse events to patients or staff.Abnormal findings appeared in 12 patients — increased FLAIR signal (n=12), hemorrhage (n=3)and diffusion-weighted positivity (n=3). Imaging changed clinical management in five patients(~25%), including diagnosis of venous thrombosis and cerebral infarction and decisions onlumbar puncture and palliative care.
Pediatric – Traumatic Brain Injury
Traumatic Brain Contusion Assessment by Bedside, Portable MRI (2024)
Study: Case report describing a child with a traumatic brain contusion who underwent portable, point-of-care MRI in the pediatric ICU. In TBI an initial CT is typically followed by a second study 6–24hours later to look for evolving injury; here a bedside pMRI was used instead to avoid additionalradiation and the workflow demands and adverse-event risk of bundling and transporting a childto a fixed CT or MR scanner.
Key Findings: The portable, bedside MR scan revealed new information that had not been appreciated on theadmission CT, contributing to assessment of the contusion and the surrounding injury. The caseillustrates pMRI’s ability to add diagnostic value at the bedside in the acute pediatric traumasetting, where repeat imaging is the norm.
Study: Illustrative case of a 10-year-old boy with severe traumatic brain injury admitted to the pediatricICU with an intracranial bolt (ICB) placed for intracranial-pressure monitoring. Initial CT showed aleft-sided intraparenchymal hemorrhage with intraventricular extension and mass effect, andcontinually fluctuating ICP demanded repeated imaging — yet transferring the unstable, ICB-bearing child to the radiology suite was hazardous and conventional MRI is sensitive to theferromagnetic implant.
Key Findings: A 0.064-T portable MRI was performed at the bedside and produced excellent-quality imageswith no ICB artifact, guiding the decision to continue conservative management. The childsubsequently improved and was discharged, illustrating that pMRI can image patients insituations previously considered contraindications for conventional MRI.
Pediatric – Ventricular Volume
Key Findings: Estimated ventricular volumes from low-field portable MRI showed excellent agreement withstandard of care — a mean bias of just 2.06% on Bland-Altman analysis and a correlation of 0.99.Because increased ventricular volume in infants is linked to impaired neurodevelopmental,motor and language outcomes, accurate bedside tracking of ventricular size is clinicallymeaningful.
