Diffusion-Weighted Imaging Fluid-Attenuated Inversion Recovery Mismatch on Portable, Low-Field Magnetic Resonance Imaging Among Acute Stroke Patients.

OBJECTIVE: For stroke patients with unknown time of onset, mismatch between diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) can guide thrombolytic intervention. However, access to MRI for hyperacute stroke is limited. Here, we sought to evaluate whether a portable, low-field (LF)-MRI scanner can identify DWI-FLAIR mismatch in acute ischemic stroke. METHODS: Eligible patients with a diagnosis of acute ischemic stroke underwent LF-MRI acquisition on a 0.064-T scanner within 24 h of last known well. Qualitative and quantitative metrics were evaluated. Two trained assessors determined the visibility of stroke lesions on LF-FLAIR. An image coregistration pipeline was developed, and the LF-FLAIR signal intensity ratio (SIR) was derived. RESULTS: The study included 71 patients aged 71 ± 14 years and a National Institutes of Health Stroke Scale of 6 (interquartile range 3-14). The interobserver agreement for identifying visible FLAIR hyperintensities was high (κ = 0.85, 95% CI 0.70-0.99). Visual DWI-FLAIR mismatch had a 60% sensitivity and 82% specificity for stroke patients <4.5 h, with a negative predictive value of 93%. LF-FLAIR SIR had a mean value of 1.18 ± 0.18 <4.5 h, 1.24 ± 0.39 4.5-6 h, and 1.40 ± 0.23 >6 h of stroke onset. The optimal cut-point for LF-FLAIR SIR was 1.15, with 85% sensitivity and 70% specificity. A cut-point of 6.6 h was established for a FLAIR SIR <1.15, with an 89% sensitivity and 62% specificity. INTERPRETATION: A 0.064-T portable LF-MRI can identify DWI-FLAIR mismatch among patients with acute ischemic stroke. Future research is needed to prospectively validate thresholds and evaluate a role of LF-MRI in guiding thrombolysis among stroke patients with uncertain time of onset. ANN NEUROL 2024;96:321-331.

In vivo T1 mapping of neonatal brain tissue at 64 mT.

PURPOSE: Ultralow-field (ULF) point-of-care MRI systems allow image acquisition without interrupting medical provision, with neonatal clinical care being an important potential application. The ability to measure neonatal brain tissue T1 is a key enabling technology for subsequent structural image contrast optimization, as well as being a potential biomarker for brain development. Here we describe an optimized strategy for neonatal T1 mapping at ULF. METHODS: Examinations were performed on a 64-mT portable MRI system. A phantom validation experiment was performed, and a total of 33 in vivo exams were acquired from 28 neonates with postmenstrual age ranging from 31+4 to 49+0  weeks. Multiple inversion-recovery turbo spin-echo sequences were acquired with differing inversion and repetition times. An analysis pipeline incorporating inter-sequence motion correction generated proton density and T1 maps. Regions of interest were placed in the cerebral deep gray matter, frontal white matter, and cerebellum. Weighted linear regression was used to predict T1 as a function of postmenstrual age. RESULTS: Reduction of T1 with postmenstrual age is observed in all measured brain tissue; the change in T1 per week and 95% confidence intervals is given by dT1  = -21 ms/week [-25, -16] (cerebellum), dT1  = -14 ms/week [-18, -10] (deep gray matter), and dT1  = -35 ms/week [-45, -25] (white matter). CONCLUSION: Neonatal T1 values at ULF are shorter than those previously described at standard clinical field strengths, but longer than those of adults at ULF. T1 reduces with postmenstrual age and is therefore a candidate biomarker for perinatal brain development.

Assessing the SAfety and FEasibility of bedside portable low-field brain Magnetic Resonance Imaging in patients on ECMO (SAFE-MRI ECMO study): study protocol and first case series experience.

BACKGROUND: To assess the safety and feasibility of imaging of the brain with a point-of-care (POC) magnetic resonance imaging (MRI) system in patients on extracorporeal membrane oxygenation (ECMO). Early detection of acute brain injury (ABI) is critical in improving survival for patients with ECMO support. METHODS: Patients from a single tertiary academic ECMO center who underwent head CT (HCT), followed by POC brain MRI examinations within 24 h following HCT while on ECMO. Primary outcomes were safety and feasibility, defined as completion of MRI examination without serious adverse events (SAEs). Secondary outcome was the quality of MR images in assessing ABIs. RESULTS: We report 3 consecutive adult patients (median age 47 years; 67% male) with veno-arterial (n = 1) and veno-venous ECMO (n = 2) (VA- and VV-ECMO) support. All patients were imaged successfully without SAEs. Times to complete POC brain MRI examinations were 34, 40, and 43 min. Two patients had ECMO suction events, resolved with fluid and repositioning. Two patients were found to have an unsuspected acute stroke, well visualized with MRI. CONCLUSIONS: Adult patients with VA- or VV-ECMO support can be safely imaged with low-field POC brain MRI in the intensive care unit, allowing for the assessment of presence and timing of ABI.

Detection of Acute Brain Injury in Intensive Care Unit Patients on ECMO Support Using Ultra-Low-Field Portable MRI: A Retrospective Analysis Compared to Head CT.

Early detection of acute brain injury (ABI) is critical to intensive care unit (ICU) patient management and intervention to decrease major complications. Head CT (HCT) is the standard of care for the assessment of ABI in ICU patients; however, it has limited sensitivity compared to MRI. We retrospectively compared the ability of ultra-low-field portable MR (ULF-pMR) and head HCT, acquired within 24 h of each other, to detect ABI in ICU patients supported on extracorporeal membrane oxygenation (ECMO). A total of 17 adult patients (median age 55 years; 47% male) were included in the analysis. Of the 17 patients assessed, ABI was not observed on either ULF-pMR or HCT in eight patients (47%). ABI was observed in the remaining nine patients with a total of 10 events (8 ischemic, 2 hemorrhagic). Of the eight ischemic events, ULF-pMR observed all eight, while HCT only observed four events. Regarding hemorrhagic stroke, ULF-pMR observed only one of them, while HCT observed both. ULF-pMR outperformed HCT for the detection of ABI, especially ischemic injury, and may offer diagnostic advantages for ICU patients. The lack of sensitivity to hemorrhage may improve with modification of the imaging acquisition program.

Clinical Use of Bedside Portable Low-field Brain Magnetic Resonance Imaging in Patients on ECMO: The Results from Multicenter SAFE MRI ECMO Study.

Purpose: Early detection of acute brain injury (ABI) is critical for improving survival for patients with extracorporeal membrane oxygenation (ECMO) support. We aimed to evaluate the safety of ultra-low-field portable MRI (ULF-pMRI) and the frequency and types of ABI observed during ECMO support. Methods: We conducted a multicenter prospective observational study (NCT05469139) at two academic tertiary centers (August 2022-November 2023). Primary outcomes were safety and validation of ULF-pMRI in ECMO, defined as exam completion without adverse events (AEs); secondary outcomes were ABI frequency and type. Results: ULF-pMRI was performed in 50 patients with 34 (68%) on venoarterial (VA)-ECMO (11 central; 23 peripheral) and 16 (32%) with venovenous (VV)-ECMO (9 single lumen; 7 double lumen). All patients were imaged successfully with ULF-pMRI, demonstrating discernible intracranial pathologies with good quality. AEs occurred in 3 (6%) patients (2 minor; 1 serious) without causing significant clinical issues.ABI was observed in ULF-pMRI scans for 22 patients (44%): ischemic stroke (36%), intracranial hemorrhage (6%), and hypoxic-ischemic brain injury (4%). Of 18 patients with both ULF-pMRI and head CT (HCT) within 24 hours, ABI was observed in 9 patients with 10 events: 8 ischemic (8 observed on ULF-oMRI, 4 on HCT) and 2 hemorrhagic (1 observed on ULF-pMRI, 2 on HCT). Conclusions: ULF-pMRI was shown to be safe and valid in ECMO patients across different ECMO cannulation strategies. The incidence of ABI was high, and ULF-pMRI may more sensitive to ischemic ABI than HCT. ULF-pMRI may benefit both clinical care and future studies of ECMO-associated ABI.

Feasibility of and experience using a portable MRI scanner in the neonatal intensive care unit.

OBJECTIVE: A portable, low-field MRI system is now Food and Drug Administration cleared and has been shown to be safe and useful in adult intensive care unit settings. No neonatal studies have been performed. The objective is to assess our preliminary experience and assess feasibility of using the portable MRI system at the bedside in a neonatal intensive care unit (NICU) at a quaternary children's hospital. STUDY DESIGN: This was a single-site prospective cohort study in neonates ≥2 kg conducted between October and December 2020. All parents provided informed consent. Neonates underwent portable MRI examination in the NICU with support equipment powered on and attached to the neonate during the examination. A paediatric radiologist interpreted each portable MRI examination. The study outcome variable was percentage of portable MRI examinations completed without artefacts that would hinder diagnosis. Findings were compared between portable MRI examinations and standard of care examinations. RESULTS: Eighteen portable, low-field MRI examinations were performed on 14 neonates with an average age of 29.7 days (range 1-122 days). 94% (17 of 18) of portable MRI examinations were acquired without significant artefact. Significant intracranial pathology was visible on portable MRI, but subtle abnormalities were missed. The examination reads were concordant in 59% (10 of 17) of cases and significant pathology was missed in 12% (2 of 17) of cases. CONCLUSION: This single-centre series demonstrated portable MRI examinations can be performed safely with standard patient support equipment present in the NICU. These findings demonstrate that portable MRI could be used in the future to guide care in the NICU setting. TRIAL REGISTRATION NUMBER: NCT04629469.

Safety of Bedside Portable Low-Field Brain MRI in ECMO Patients Supported on Intra-Aortic Balloon Pump.

(1) Background: Fifty percent of patients supported on veno-arterial extracorporeal membrane oxygenation (VA-ECMO) are concurrently supported with an intra-aortic balloon pump (IABP). Acute brain injury (ABI) is a devastating complication related to ECMO and IABP use. The standard of care for ABI diagnosis requires transport to a head CT (HCT) scanner. Recent data suggest that point-of-care (POC) magnetic resonance imaging (MRI) is safe and may be effective in diagnosing ABI in ECMO patients; however, no data exist in patients supported on ECMO with an IABP. We report pre-clinical safety data and a case series to evaluate the safety and feasibility of POC brain MRI in ECMO patients supported with IABP. (2) Methods: Prior to patient use, ex vivo testing with an IABP catheter within the Swoop® Portable MRI (0.064 T) System™ was conducted. After IRB approval, clinical testing was performed for the safety and feasibility of early ABI detection. (3) Results: No deflection force was measured with a 7.5 French Maquet Linear IABP within the 0.064 T field. Three adult ECMO patients (average age: 40 years; 67% female) supported with IABP completed four POC brain MRI exams (median exam time: 30 min). Multiple signal abnormalities were detected on the POC brain MRI, corresponding to HCT results. (4) Conclusions: Our preliminary results suggest that adult VA-ECMO patients with IABP support can be safely imaged with low-field POC brain MRI in the intensive care unit, allowing for the early and bedside imaging of patients.

Sodium bisulfate feed additive aids broilers in growth and intestinal health during a coccidiosis challenge.

Sodium bisulfate (SB) was evaluated on its ability to improve broiler growth and intestinal structure with(out) a coccidia challenge. One thousand two hundred Cobb500 day-old males were randomly assigned within 4 experimental groups with a 2 × 2 factorial design, with (out) SB in the diet and with(out) a day 0 coccidia challenge using a 10× dose of a commercial vaccine. At day 7, oocysts per gram of feces were determined. At day 0, 14, 28, and 41, BW and feed consumption were measured. At day 21, 20 birds per treatment were subjectively scored for coccidia lesions, and jejunal histologic samples were collected for villi measurements. Twenty additional birds were given fluorescein isothiocyanate-dextran to determine gut permeability. At day 41, 10 birds per treatment had histologic samples collected. Statistical analysis was conducted in JMP Pro 14 using GLM procedure to compare disease state and diet. Means were separated using Dunnett's test (P ≤ 0.05) with the nonchallenged standard diet treatment that is considered the control. All parameters measured indicated an effect due to the coccidia inoculation. Therefore, effects of diet on (non)challenged treatments were determined using a Student t test (P ≤ 0.05). Limited differences due to diet were seen for the nonchallenged production data. Sodium bisulfate had a thinner villi base width (P = 0.04) on day 21 and greater villi height (P = 0.03), smaller base width (P = 0.04), thicker muscularis (P = 0.03), and lower crypt: height ratio (P = 0.01) on day 41. Challenged SB had similar gut permeability to the nonchallenged control (P = 0.94) on day 21. There was no difference in flock uniformity, feed intake, oocysts per gram of feces, or lesion scores between challenged treatments. Challenged SB had greater BW on day 14 (P < 0.0001), 28 (P < 0.0001), and 41 (P = 0.02). Feed conversion ratio from day 0 to 14 was also lower (P = 0.0002). Challenged SB had smaller crypts (P = 0.02) and therefore a smaller crypt: height ratio (P = 0.03) on day 21. Challenged control had a larger apical width (P = 0.03) and thicker muscularis (P = 0.04) on day 41. Overall, the addition of SB during coccidial enteropathy aided in BW, feed conversion ratio, and villi health with no observed effects on parasite cycling.

Hepatocellular carcinoma presenting as orbital bone metastasis.

The authors present 2 patients in the first description of hepatocellular carcinoma metastasis to the greater wing of the sphenoid. MRI of the first case showed a multilobulated lesion, of signal intensity similar to cerebrospinal fluid in all sequences, replacing the greater wing of the sphenoid and extending in the orbit, temporalis, and middle cranial fossa. CT of the second case also showed triple fossa extension of a destructive lesion in the greater wing of the sphenoid. Fine needle aspiration biopsy showed metastatic hepatocellular carcinoma in both cases.

Isotropic 3D fast spin-echo with proton-density-like contrast: a comprehensive approach to musculoskeletal MRI.

OBJECTIVE: Scanning time considerations have restricted routine use of 3D Fourier transform (3DFT)-encoded MRI to gradient-recalled echo sequences. We sought to combine isotropic 3DFT acquisition with fast spin-echo at a practical scan duration. This strategy offers versatile image contrast for musculoskeletal evaluation and facilitates image reformation tailored to the depiction of small anatomic features. CONCLUSION: Isotropic 3DFT fast spin-echo is feasible on current MRI scanners and has the potential to improve musculoskeletal evaluation.

Bright and black blood imaging of the carotid bifurcation at 3.0T.

PURPOSE: The aim of this study was to evaluate our preliminary experience at 3.0 T with imaging of the carotid bifurcation in healthy and atherosclerotic subjects. Application at 3.0 T is motivated by the signal-to-noise gain for improving spatial resolution and reducing signal averaging requirements. MATERIALS AND METHODS: We utilized a dual phased array coil and applied 2D, 3D time of flight (TOF) and turbo spin echo (TSE) sequences with comparison of two lumen signal suppression methods for black blood (BB) TSE imaging including double inversion preparation (DIR) and spatial presaturation pulses. The signal-to-noise ratios (SNR) of healthy carotid vessel walls were compared in 2D and 3D BB TSE acquisitions. The bright and black blood multi-contrast exam was demonstrated for a complex carotid plaque. RESULTS: Contrast-to-noise (CNR) greater than 150 was achieved between the lumen and suppressed background for 3D TOF. For BB, both methods provided sufficient lumen signal suppression but slight residual flow artifacts remained at the bifurcation level. As expected 3D TSE images had higher SNR compared to 2D, but increased motion sensitivity is a significant issue for 3D at high field. For multi-contrast imaging of atherosclerotic plaque, fibrous, calcified and lipid components were resolved. The CNR ratio of fibrous (bright on PDW, T2W) and calcified (dark in T1W, T2W, PDW) plaque components was maximal in the T2W images. The 3D TOF angiogram indicating a 40% stenosis was complemented by 3D multi-planar reformat of BB images that displayed plaque extent. Detection of intimal thickening, the earliest change associated with atherosclerotic progression was observed in BB PDW images at 3.0 T. CONCLUSIONS: High SNR and CNR images have been demonstrated for the healthy and diseased carotid. Improvements in RF coils along with pulse sequence optimization, and evaluation of endogenous and exogenous contrast mechanisms will further enhance carotid imaging at 3.0T.

Management and recruitment of general practitioners with special interests: roles and responsibilities of primary care organisations.

WHAT IS ALREADY KNOWN IN THIS AREA • Special Interest posts are being developed to help meet targets for patient care. • Planning, is haphazard and varied. • Many issues are unaddressed. WHAT THIS WORK ADDS • There is a dichotomy of interest between planning by primary care organizations, for example, in the setting of disciplines needed, and funding levels and sources. SUGGESTIONS FOR FUTURE RESEARCH • Research is needed to demonstrate whether such posts fulfil expectations without adversely affecting healthcare in other areas. • Appraisal and continuing professional development issues need to be addressed at a national level.

Becoming a general practice trainer: experience of higher preparatory training.

WHAT IS ALREADY KNOWN IN THIS AREA • Basic training courts for general; practice trainers; do not always meet the demands for the level of 'professionalition' expected. • Many regions now run university-accredited teaching bourses, some of which advocate compulsion. WHAT THIS WORK ADDS • This work has shown that a mandatory course is generally accepted by participants. • Organisational infrastructure needs to be efficient. SUGGESTIONS FOR FUTURE RESEARCH • The effects on trainer recruitment need to be monitored and studied. • The effects on further individual continuing professional development in terms of following this initial course towards a diploma or higher degree.

Anterior cruciate ligament tears treated with percutaneous injection of autologous bone marrow nucleated cells: a case series.

INTRODUCTION: This was a prospective case series designed to investigate treatment for anterior cruciate ligament (ACL) tears using an injection of autologous bone marrow concentrate. METHODS: Consecutive adult patients presenting to a private outpatient interventional musculoskeletal and pain practice with knee pain, ACL laxity on exam, and magnetic resonance imaging (MRI) evidence of a grade 1, 2, or 3 ACL tears with less than 1 cm retraction were eligible for this study. Eligible patients were treated with an intraligamentous injection of autologous bone marrow concentrate, using fluoroscopic guidance. Pre- and postprocedural sagittal MRI images of the ACLs were analyzed using ImageJ software to objectively quantify changes between pre- and posttreatment scans. Five different types of measurement of ACL pixel intensity were examined as a proxy for ligament integrity. In addition pain visual analog scale (VAS) and Lower Extremity Functional Scale (LEFS) values were recorded at baseline and at 1 month, 3 months, 6 months, and annually postinjection. Objective outcomes measured were pre- to post-MRI measurement changes, as analyzed by the ImageJ software. Subjective outcomes measured were changes in the VAS and LEFS, and a self-rated percentage improvement. RESULTS: Seven of ten patients showed improvement in at least four of five objective measures of ACL integrity in their postprocedure MRIs. In the entire study group, the mean gray value, median, raw integrated density, and modal gray value all decreased toward low-signal ACLs (P=0.01, P=0.02, P=0.002, and P=0.08), indications of improved ligament integrity. Seven of ten patients responded to the self-rated metrics follow up. The mean VAS change was a decrease of 1.7 (P=0.25), the mean LEFS change was an increase of 23.3 (P=0.03), and mean reported improvement was 86.7%. CONCLUSION: Based on this small case series, autologous bone marrow concentrate shows promise in the treatment of grade 1, 2, and possibly grade 3 ACL tears without retraction. Further investigation using a controlled study design is warranted.

Comparison of cardiac MRI on 1.5 and 3.0 Tesla clinical whole body systems.

RATIONALE AND OBJECTIVES: A cardiac imaging pilot study was performed on 1.5 and 3.0 Tesla (T) whole body magnetic resonance units equipped with identical gradient sets and geometrically equivalent body coils. The goals were to compare the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios on matched studies conducted at both field strengths and demonstrate the potential for functional and morphologic cardiac evaluation at 3.0 T. METHODS: Short axis cine true fast imaging with steady precession (True FISP) was compared at 1.5 and 3.0 T using the body coil in transmit-receive mode and transmit-only with single loop and phased array receiver coils. SNR of the myocardium and CNR of the ventricular blood and myocardium were calculated from a quantitative region of interest analysis of these data. Additionally at 3.0 T, long axis and 4-chamber cine as well as "dark blood" imaging are demonstrated with sequence and parameter settings comparable to current state of the art for cardiac evaluation at 1.5 T. RESULTS: The 3.0 T data consistently demonstrates increases in SNR when all imaging conditions are closely matched but the increase has a large variability ranging from 20 to 85% depending on the radiofrequency coil configuration. Ventricular blood-myocardium CNR greater than 30 is obtained at 3.0 T, which is comparable to an optimized 1.5 T acquisition despite the specific absorption rate limitation of flip angle to nearly one half the value. The increased SNR at 3.0 T improves detection of fine anatomic detail, such as the chordae tendineae and mitral valve structure. CONCLUSIONS: Increased specific absorption rate can be a limiting fact; however, we have demonstrated that 3.0 T cardiac imaging shows gains in SNR while maintaining the CNR. The SNR gain is advantageous, and phased array coil technology is key for improving cardiac magnetic resonance imaging at 3.0 T.

Enhancing reliability in portfolio assessment: 'shaping' the portfolio.

This paper reports a follow-on project that assessed a series of portfolios assembled by a cohort of participants attending a course for prospective general practice trainers. In an attempt to enhance reliability, a framework for defining and addressing problems using a reflective practice model was offered to participants. The reliability of the judgements made by a panel of assessors about individual 'components', together with an overall global judgement about performance were studied. The reliability of individual assessors' judgements (i.e. their consistency) was moderate, but inter-rater reliability did not reach a level that could support making a safe summative judgement. Despite offering a possible structure for demonstrating reflective processes, the levels of reliability reached were similar to the earlier work and other subjective assessments generally, and perhaps reflected individuality of personal agendas of both the assessed and the assessors, and variations in portfolio structure and content; even agreement among the assessors about evidence of the framework being used was poor. Suggestions for approaches in the future are made. The conclusion remains that while portfolios might be valuable as resources for learning, as assessment tools they should be treated as problematic.

Efficacy of autologous bone marrow concentrate for knee osteoarthritis with and without adipose graft.

INTRODUCTION: We investigated the use of autologous bone marrow concentrate (BMC) with and without an adipose graft, for treatment of knee osteoarthritis (OA). METHODS: Treatment registry data for patients who underwent BMC procedures with and without an adipose graft were analyzed. Pre- and posttreatment outcomes of interest included the lower extremity functional scale (LEFS), the numerical pain scale (NPS), and a subjective percentage improvement rating. Multivariate analyses were performed to examine the effects of treatment type adjusting for potential confounding factors. The frequency and type of adverse events (AE) were also examined. RESULTS: 840 procedures were performed, 616 without and 224 with adipose graft. The mean LEFS score increased by 7.9 and 9.8 in the two groups (out of 80), respectively, and the mean NPS score decreased from 4 to 2.6 and from 4.3 to 3 in the two groups, respectively. AE rates were 6% and 8.9% in the two groups, respectively. Although pre- and posttreatment improvements were statistically significant, the differences between the groups were not. CONCLUSION: BMC injections for knee OA showed encouraging outcomes and a low rate of AEs. Addition of an adipose graft to the BMC did not provide a detectible benefit over BMC alone.