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Low field portable MRI (LF pMRI) is a new imaging tool that holds promise in offering a safe, cost-effective, point-of-care imaging solution in neuroimaging. There are however unique interpretive challenges and operational factors and limitations in its implementation in clinical practice. This paper aims to provide a comprehensive guide on the tips and tricks of interpreting LF pMRI, specifically the Hyperfine Swoop® MRI system, which operates at 0.064 T and is currently the only FDA and Health Canada approved LF pMRI system. This paper explores the operational aspects and interpretation challenges of low-field MRI, such as patient positioning, protocol selection, and the appearance of artifacts and common pathologies. Using illustrative examples, we aim to guide current and future operators of LF pMRI to optimize performance, provide accurate diagnoses, and avoid common pitfalls.

Background Alzheimer’s disease (AD) poses a substantial healthcare challenge. Current immunotherapy targeting beta‐amyloid (Aβ) while representing a significant advancement, may be accompanied by potential complications such as amyloid‐related imaging abnormalities (ARIA). ARIA monitoring via high‐field MRI encounters logistical hurdles, exacerbated by regulatory demands for frequent MRI surveillance. This study investigates the integration of a portable ultra‐low field MRI into AD patient monitoring during immunotherapy to optimize ARIA detection, overall workflow and treatment outcomes. Method This prospective observational study recruits clinical patients with mild cognitive impairment due to Alzheimer disease underlying evaluation and monitoring for anti‐amyloid monoclonal antibody therapy. Baseline pre‐therapy 3T MRI will serve as a reference for subsequent imaging assessments. Participants undergo Hyperfine Swoop MRI scans at 0.064 tesla alongside their baseline and subsequent sessions, encompassing T1‐weighted, T2‐weighted, FLAIR, and DWI‐ADC sequences. Monitoring extends for 12 months after the initial clinic visit, enabling real‐time treatment response evaluation. Each participant will undergo ∼5 paired imaging visits, according to the therapy FDA label. Result Effectiveness of high‐field and low‐field longitudinal imaging sessions will be compared for detection and evaluation of moderate and severe ARIA‐E (edema). A randomized, blinded assessment approach will be used to evaluate differences in radiologist assessment and treatment plan between field strengths. Patient imaging workflow improvement will be assessed using a survey. Conclusion The Hyperfine Swoop MRI, with its portability and accessibility, shows promise as a cost‐effective alternative to the standard 3T MRI with the significant value‐added benefit of optimization of workflow. Further research is needed to confirm these benefits in larger cohorts and assess long‐term reliability. Overall, our study highlights the potential of innovative imaging technologies in improving patient care, monitoring neurodegenerative diseases thereby establishing a more equitable scheme for patient care.

Background White matter hyperintensities (WMH) are known predictors of amyloid‐related imaging abnormalities (ARIA) in patients undergoing anti‐amyloid immunotherapy (AAT) for Alzheimer disease. WMHs and brain volumetric changes can potentially be captured by low‐field magnetic resonance imaging (MRI) that imposes minimal safety risks to those with contraindicators to high‐field MRI. We investigate the recently released FreeSurfer WMH‐SynthSeg for volumetric and WMH lesion processing of low‐field MRI and its comparability to 3T MRI. Method Low‐field head MRI scans for 19 healthy controls and 23 patients undergoing AAT were acquired on a 0.064T Hyperfine SwoopÒ Portable MRI scanner. Treated patients also underwent a 3T MRI for ARIA screening by a clinical neuro‐radiologist per treatment protocol. Volumetric measures of cortical grey matter, white matter, ventricles, and hippocampus were extracted from WMH‐SynthSeg for low‐field and FreeSurfer‐7.4 for 3T MRI. WMH lesion probability maps were generated for all participants from WMH‐SynthSeg. Linear regressions examined agreement between volumetrics for low‐field and 3T MRI in treated patients without ARIA. Spatial localization of WMH lesions with ARIA pathology were visually assessed and compared with the clinical 3T scan. Finally, WMH volume measures were assessed amongst healthy controls and patients with and without ARIA using a pairwise Wilcoxon with Benjamini‐Hochberg correction for multiple comparisons. Result Four patients were clinically identified as having ARIA with cerebral edema (ARIA‐E) from 3T MRI. WMH‐SynthSeg estimates of lateral ventricular, white matter, and cortical grey matter volumes agreed with 3T MRI but tended to be significantly underestimated for the hippocampus (Figure 1). WMH lesion probability maps aligned with known ARIA but failed to capture the entire area affected (Figure 2). While WMH volumes for healthy controls were significantly lower than those on AAT therapy, WMH volumes were not significantly different between AAT patients with and without ARIA‐E (Figure 3). Conclusion WMH‐SynthSeg provides comparable volumetric measures to 3T for large brain regions and can spatially capture known ARIA. However, in our small sample, these measures were not sensitive enough to fully identify areas of ARIA. Further development is needed to improve small region quantification and WMH lesion detection, particularly at low‐fields.

Lecanemab is an anti-beta-amyloid immunotherapy approved by the FDA in 2023 for Alzheimer's Disease (AD). One known side effect is the development of amyloid-related imaging abnormalities (ARIA), manifesting as cerebral edema (ARIA-E), or microhemorrhage with siderosis (ARIA-H). Appropriate use recommendations for lecanemab recommend brain MRI (clinical scan) at baseline, and approximately 4.5 months, 5.5 months, and 9 months into therapy. The requirement for these scans and the limitations of access to MRI-capable facilities levies significant burdens on patients, their caregivers, and facilities. Patients who may otherwise benefit have been without this therapy due to lack of MRI access. We aim to demonstrate the viability of an ultra-low field, portable MRI as an appropriate vehicle for baseline and safety monitoring. 31 patients with AD on lecanemab therapy or off due to known ARIA were recruited for the study. Participants underwent MRI on the low-field 0.064T Hyperfine Swoop® Portable MR Imaging® system within 1 week of their corresponding clinical screening MRI. Historical data collected from the medical record included age, the reads of baseline and any prior monitoring scans, and ARIA history. The average age of participants was 74.6, and 54.8% were female. 44 scans were obtained on the low-field MRI that were paired temporally with their clinical counterparts (Figure 1). In total, 14 clinical scans read by a neuroradiologist had at least 1 type and 1 degree of ARIA. Of these, 7 had Mild ARIA-E, 4 Moderate ARIA-E, and 8 ARIA-H (mild to severe). 2 separate, independent neuroradiologists identified all cases of ARIA-E (mild and moderate, Figure 2) on the low-field MRI scans. None of the 8 cases of ARIA-H could be identified on low-field MRI scans. 1 incidental finding of subdural hematoma (SDH) that was read on a clinical scan was identifiable on its low-field MRI counterpart (Figure 3). We found the low-field MRI to have a 100% sensitivity for both mild and moderate ARIA-E, but was not sensitive to microhemorrhages. Should this portable MRI modality be further as an adequate surrogate for 1.5/3T clinical scans, it could ease burdens on patients, their caregivers, and hospitals.

Background White matter hyperintensities (WMH) are known predictors of amyloid‐related imaging abnormalities (ARIA) in patients undergoing anti‐amyloid immunotherapy (AAT) for Alzheimer disease. WMHs and brain volumetric changes can potentially be captured by low‐field magnetic resonance imaging (MRI) that imposes minimal safety risks to those with contraindicators to high‐field MRI. We investigate the recently released FreeSurfer WMH‐SynthSeg for volumetric and WMH lesion processing of low‐field MRI and its comparability to 3T MRI. Method Low‐field head MRI scans for 19 healthy controls and 23 patients undergoing AAT were acquired on a 0.064T Hyperfine SwoopÒ Portable MRI scanner. Treated patients also underwent a 3T MRI for ARIA screening by a clinical neuro‐radiologist per treatment protocol. Volumetric measures of cortical grey matter, white matter, ventricles, and hippocampus were extracted from WMH‐SynthSeg for low‐field and FreeSurfer‐7.4 for 3T MRI. WMH lesion probability maps were generated for all participants from WMH‐SynthSeg. Linear regressions examined agreement between volumetrics for low‐field and 3T MRI in treated patients without ARIA. Spatial localization of WMH lesions with ARIA pathology were visually assessed and compared with the clinical 3T scan. Finally, WMH volume measures were assessed amongst healthy controls and patients with and without ARIA using a pairwise Wilcoxon with Benjamini‐Hochberg correction for multiple comparisons. Result Four patients were clinically identified as having ARIA with cerebral edema (ARIA‐E) from 3T MRI. WMH‐SynthSeg estimates of lateral ventricular, white matter, and cortical grey matter volumes agreed with 3T MRI but tended to be significantly underestimated for the hippocampus (Figure 1). WMH lesion probability maps aligned with known ARIA but failed to capture the entire area affected (Figure 2). While WMH volumes for healthy controls were significantly lower than those on AAT therapy, WMH volumes were not significantly different between AAT patients with and without ARIA‐E (Figure 3). Conclusion WMH‐SynthSeg provides comparable volumetric measures to 3T for large brain regions and can spatially capture known ARIA. However, in our small sample, these measures were not sensitive enough to fully identify areas of ARIA. Further development is needed to improve small region quantification and WMH lesion detection, particularly at low‐fields.

Background Lecanemab is an anti‐beta‐amyloid immunotherapy approved by the FDA in 2023 for Alzheimer’s Disease (AD). One known side effect is the development of amyloid‐related imaging abnormalities (ARIA), manifesting as cerebral edema (ARIA‐E), or microhemorrhage with siderosis (ARIA‐H). Appropriate use recommendations for lecanemab recommend brain MRI (clinical scan) at baseline, and approximately 4.5 months, 5.5 months, and 9 months into therapy. The requirement for these scans and the limitations of access to MRI‐capable facilities levies significant burdens on patients, their caregivers, and facilities. Patients who may otherwise benefit have been without this therapy due to lack of MRI access. We aim to demonstrate the viability of an ultra‐low field, portable MRI as an appropriate vehicle for baseline and safety monitoring. Method 31 patients with AD on lecanemab therapy or off due to known ARIA were recruited for the study. Participants underwent MRI on the low‐field 0.064T Hyperfine Swoop® Portable MR Imaging® system within 1 week of their corresponding clinical screening MRI. Historical data collected from the medical record included age, the reads of baseline and any prior monitoring scans, and ARIA history. The average age of participants was 74.6, and 54.8% were female. Result 44 scans were obtained on the low‐field MRI that were paired temporally with their clinical counterparts (Figure 1). In total, 14 clinical scans read by a neuroradiologist had at least 1 type and 1 degree of ARIA. Of these, 7 had Mild ARIA‐E, 4 Moderate ARIA‐E, and 8 ARIA‐H (mild to severe). 2 separate, independent neuroradiologists identified all cases of ARIA‐E (mild and moderate, Figure 2) on the low‐field MRI scans. None of the 8 cases of ARIA‐H could be identified on low‐field MRI scans. 1 incidental finding of subdural hematoma (SDH) that was read on a clinical scan was identifiable on its low‐field MRI counterpart (Figure 3). Conclusion We found the low‐field MRI to have a 100% sensitivity for both mild and moderate ARIA‐E, but was not sensitive to microhemorrhages. Should this portable MRI modality be further as an adequate surrogate for 1.5/3T clinical scans, it could ease burdens on patients, their caregivers, and hospitals.

Lecanemab is an anti-beta-amyloid immunotherapy approved by the FDA in 2023 for Alzheimer's Disease (AD). One known side effect is the development of amyloid-related imaging abnormalities (ARIA), manifesting as cerebral edema (ARIA-E), or microhemorrhage with siderosis (ARIA-H). Appropriate use recommendations for lecanemab recommend brain MRI (clinical scan) at baseline, and approximately 4.5 months, 5.5 months, and 9 months into therapy. The requirement for these scans and the limitations of access to MRI-capable facilities levies significant burdens on patients, their caregivers, and facilities. Patients who may otherwise benefit have been without this therapy due to lack of MRI access. We aim to demonstrate the viability of an ultra-low field, portable MRI as an appropriate vehicle for baseline and safety monitoring. 31 patients with AD on lecanemab therapy or off due to known ARIA were recruited for the study. Participants underwent MRI on the low-field 0.064T Hyperfine Swoop® Portable MR Imaging® system within 1 week of their corresponding clinical screening MRI. Historical data collected from the medical record included age, the reads of baseline and any prior monitoring scans, and ARIA history. The average age of participants was 74.6, and 54.8% were female. 44 scans were obtained on the low-field MRI that were paired temporally with their clinical counterparts (Figure 1). In total, 14 clinical scans read by a neuroradiologist had at least 1 type and 1 degree of ARIA. Of these, 7 had Mild ARIA-E, 4 Moderate ARIA-E, and 8 ARIA-H (mild to severe). 2 separate, independent neuroradiologists identified all cases of ARIA-E (mild and moderate, Figure 2) on the low-field MRI scans. None of the 8 cases of ARIA-H could be identified on low-field MRI scans. 1 incidental finding of subdural hematoma (SDH) that was read on a clinical scan was identifiable on its low-field MRI counterpart (Figure 3). We found the low-field MRI to have a 100% sensitivity for both mild and moderate ARIA-E, but was not sensitive to microhemorrhages. Should this portable MRI modality be further as an adequate surrogate for 1.5/3T clinical scans, it could ease burdens on patients, their caregivers, and hospitals.

Background Lecanemab is an anti‐beta‐amyloid immunotherapy approved by the FDA in 2023 for Alzheimer's Disease (AD). One known side effect is the development of amyloid‐related imaging abnormalities (ARIA), manifesting as cerebral edema (ARIA‐E), or microhemorrhage with siderosis (ARIA‐H). Appropriate use recommendations for lecanemab recommend brain MRI (clinical scan) at baseline, and approximately 4.5 months, 5.5 months, and 9 months into therapy. The requirement for these scans and the limitations of access to MRI‐capable facilities levies significant burdens on patients, their caregivers, and facilities. Patients who may otherwise benefit have been without this therapy due to lack of MRI access. We aim to demonstrate the viability of an ultra‐low field, portable MRI as an appropriate vehicle for baseline and safety monitoring. Method 31 patients with AD on lecanemab therapy or off due to known ARIA were recruited for the study. Participants underwent MRI on the low‐field 0.064T Hyperfine Swoop® Portable MR Imaging® system within 1 week of their corresponding clinical screening MRI. Historical data collected from the medical record included age, the reads of baseline and any prior monitoring scans, and ARIA history. The average age of participants was 74.6, and 54.8% were female. Result 44 scans were obtained on the low‐field MRI that were paired temporally with their clinical counterparts (Figure 1). In total, 14 clinical scans read by a neuroradiologist had at least 1 type and 1 degree of ARIA. Of these, 7 had Mild ARIA‐E, 4 Moderate ARIA‐E, and 8 ARIA‐H (mild to severe). 2 separate, independent neuroradiologists identified all cases of ARIA‐E (mild and moderate, Figure 2) on the low‐field MRI scans. None of the 8 cases of ARIA‐H could be identified on low‐field MRI scans. 1 incidental finding of subdural hematoma (SDH) that was read on a clinical scan was identifiable on its low‐field MRI counterpart (Figure 3). Conclusion We found the low‐field MRI to have a 100% sensitivity for both mild and moderate ARIA‐E, but was not sensitive to microhemorrhages. Should this portable MRI modality be further as an adequate surrogate for 1.5/3T clinical scans, it could ease burdens on patients, their caregivers, and hospitals.

White matter hyperintensities (WMH) are known predictors of amyloid-related imaging abnormalities (ARIA) in patients undergoing anti-amyloid immunotherapy (AAT) for Alzheimer disease. WMHs and brain volumetric changes can potentially be captured by low-field magnetic resonance imaging (MRI) that imposes minimal safety risks to those with contraindicators to high-field MRI. We investigate the recently released FreeSurfer WMH-SynthSeg for volumetric and WMH lesion processing of low-field MRI and its comparability to 3T MRI. Low-field head MRI scans for 19 healthy controls and 23 patients undergoing AAT were acquired on a 0.064T Hyperfine SwoopÒ Portable MRI scanner. Treated patients also underwent a 3T MRI for ARIA screening by a clinical neuro-radiologist per treatment protocol. Volumetric measures of cortical grey matter, white matter, ventricles, and hippocampus were extracted from WMH-SynthSeg for low-field and FreeSurfer-7.4 for 3T MRI. WMH lesion probability maps were generated for all participants from WMH-SynthSeg. Linear regressions examined agreement between volumetrics for low-field and 3T MRI in treated patients without ARIA. Spatial localization of WMH lesions with ARIA pathology were visually assessed and compared with the clinical 3T scan. Finally, WMH volume measures were assessed amongst healthy controls and patients with and without ARIA using a pairwise Wilcoxon with Benjamini-Hochberg correction for multiple comparisons. Four patients were clinically identified as having ARIA with cerebral edema (ARIA-E) from 3T MRI. WMH-SynthSeg estimates of lateral ventricular, white matter, and cortical grey matter volumes agreed with 3T MRI but tended to be significantly underestimated for the hippocampus (Figure 1). WMH lesion probability maps aligned with known ARIA but failed to capture the entire area affected (Figure 2). While WMH volumes for healthy controls were significantly lower than those on AAT therapy, WMH volumes were not significantly different between AAT patients with and without ARIA-E (Figure 3). WMH-SynthSeg provides comparable volumetric measures to 3T for large brain regions and can spatially capture known ARIA. However, in our small sample, these measures were not sensitive enough to fully identify areas of ARIA. Further development is needed to improve small region quantification and WMH lesion detection, particularly at low-fields.

Background Studies comparing primary medical treatment of acromegaly with surgery are often non-randomized, and not stratified by illness severity. We prospectively compared primary medical therapy with pituitary surgery in patients with acromegaly. All patients had macroadenomas, at least one random human growth hormone (GH) level ≥12.5 ng/mL, elevated IGF-I levels and failure to suppress GH to <1 ng/mL during an oral glucose tolerance test (oGTT). Methods Forty-one patients from seven centers were randomized to primary treatment with octreotide LAR, 30 mg every 4 weeks × 3 months (ARM A, N = 15), or pituitary surgery (ARM B, N = 26) using a 1:2 randomization design. Patients cured by surgery (defined as nadir GH during oGTT <1 ng/mL and normal IGF-I) received no subsequent treatment. Those not cured surgically were then treated with octreotide LAR (SubArm B1) for 3 months. Results Only one of the 15 patients in ARM A (6.7%) had normalization of both GH and IGF-I. In contrast, 13/26 patients had normalization of both GH and IGF-I after surgery alone (50%). Of the remaining 13 patients who did not normalize with surgery alone, treatment with octreotide LAR resulted in a normal nadir GH and normal serum IGF-I in 7 (53.9%). In total, 20/26 in ARM B (76.9%) experienced normalization of defined biochemical acromegaly parameters. Conclusions Pituitary surgery alone was more effective than primary medical treatment (p = 0.006), and the combination of surgery followed by medical therapy was even more effective (p < 0.0001). Subjects treated with medical therapy after surgical debulking had a significant improvement in response rate compared to matched subjects treated with primary medical therapy.