Background: Interstitial lung disease (ILD) encompasses several pulmonary disorders associated with scarring and fibrosis of pulmonary tissue. People with idiopathic pulmonary fibrosis, a subset of ILD, have greater central airway luminal area compared to age- and sex-matched healthy controls when evaluated using microcomputed tomography, a process examining the luminal area of ex-vivo lung tissue. In this study we aimed to confirm these findings using a different method of airway assessment, three-dimensional (3D) reconstruction of computed tomography (CT) scans. Moreover, in health, males have larger central airways than height-matched females, but it remains unknown if there are sex differences in airway area among people with ILD. We hypothesized that sex differences observed in healthy people would persist among people with ILD. Methods: A cohort of 399 patients with lung CT scans were screened, of which 19 people (7 females) with ILD were included in analyses after exclusions. People with ILD were matched based on sex, age, and height to 19 healthy controls. We assessed cross-sectional luminal area at the midpoint of seven conducting airways (trachea, left and right main bronchus, intermediate bronchus, left and right upper lobe, and left lower lobe). Results from pulmonary function tests were also abstracted, as available. To examine sex differences, we compared airway luminal area, normalized to participant height, between males and females with ILD. Sex differences were analyzed using a univariate ANOVA test. Results: People with ILD had a preserved ratio of forced expiratory volume in the first second to forced vital capacity (101 ±12%predicted) and decreased diffusing capacity for carbon monoxide (55 ±23%predicted). People with ILD had airways that were between 19.6%-45.0% larger than controls (p<0.05). Composite physiologic index, a marker of ILD severity, was not different between sexes (p=0.07). Males with ILD had significantly larger, luminal areas than females in two central airways - right main bronchus (1.46±0.41 vs. 1.07±0.22 mm 2 /cm, p=0.04) and left upper lobe (0.54±0.10 vs. 0.43±0.08 mm 2 /cm, p=0.02). However, luminal area of other central airways, including: trachea (2.15±0.57 vs. 1.65±0.32 mm 2 /cm, p=0.051), bronchus intermediate (0.77±0.23 vs. 0.61±0.13 mm 2 /cm, p=0.12), right upper lobe (0.47±0.15 vs. 0.40±0.06 mm 2 /cm, p=0.26), left main bronchus (0.93±0.33 vs. 0.69±0.16 mm 2 /cm, p=0.09), and left lower lobe (0.41±0.13 vs. 0.40±0.08 mm 2 /cm, p=0.79) were not different between sexes in people with ILD. Conclusion: Sex differences observed in healthy people are potentially preserved in ILD, but a more robust sample is required to fully elucidate these findings. Illuminating any sex differences in ILD pathophysiology may provide knowledge to treat and improve clinical outcomes in ILD. Funding: National Heart, Lung, and Blood Institute (F32HL154320 to JWS; 5R35HL139854 to MJJ). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Background: Patients with respiratory manifestations of acute COVID-19 infection have enlarged luminal areas of central conducting airways demonstrated on computed tomography imaging and abnormal pulmonary function. In some cases, COVID-19 symptoms may persist for more than 4 weeks, referred to as long COVID, and the effect on airway luminal area remains unknown. Herein, we report airway luminal cross-sections areas among a long COVID group, compared to individuals with an acute COVID-19. We aim to investigate if large conducting airways sizes are different between acute COVID-19 and long COVID patients. Methods: A cohort of 181 people with long COVID were screened, of which 20 people (9 men, 11 women; 55.9 ± 14.1 years) were included in analyses. Twenty age, height, and sex matched patients with an acute (< 4 weeks of persistent symptoms from diagnosis) COVID-19 infection (55.7 ± 15.2 years) served as a comparison group. We used a three-dimensional reconstruction of computed tomography imaging to measure luminal areas of the trachea, right and left main bronchi, bronchus intermediate, right and left upper lobe, and left lower lobe bronchi at proximal, middle, and distal cross-sectional points in both groups. Airway luminal area was taken as the average of the three points. We compared average lumen area of long COVID patients with acute COVID-19 individuals, using an independent samples t-test. Results: We found no significant difference comparing measurements of the following airway luminal cross-sectional areas: trachea (277.7 ± 100.4 vs. 268.0 ± 70.5 mm 2 p=0.73), right main bronchus (191.0 ± 66.1 vs. 190.1 ± 49.0 mm 2 , p=0.96), bronchus intermediate (112.3 ± 33.4 vs. 109.3 ± 27.9 mm 2 , p=0.76), right upper lobe bronchus (74.4 ± 21.0 vs. 73.7 ± 25.5 mm 2 , p=0.92), left main bronchus (129.1 ± 50.1 vs. 136.9 ± 38.0 mm 2 , p=0.58), left lower lobe bronchus (57.8 ± 18.2 vs. 59.0 ± 13.4 mm 2 , p=0.82), and left upper lobe bronchus (80.1 ± 19.5 vs. 77.9 ± 22.9 mm 2 , p=0.75) in the long COVID and acute COVID-19 groups respectively. Conclusion: In patients with long COVID, compared to those with an acute COVID-19 infection, we did not see differences in central airway luminal areas. Further analysis of a larger cohort is needed to determine whether enlarged airway luminal areas, associated with acute COVID-19, persist in long COVID. This research will expand knowledge on functional consequences for patients with long COVID. Funding: F32HL154320 to JWS; 5R35HL139854 to MJJ. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Background and Purpose: In stroke, timely treatment is vital for preserving neurologic function. However, decision-making in neurocritical care is hindered by limited accessibility of neuroimaging and radiological interpretation. We evaluated an artificial intelligence (AI) system for use in conjunction with bedside portable point-of-care (POC)-MRI to automatically measure midline shift (MLS), a quantitative biomarker of stroke severity. Materials and Methods: POC-MRI (0.064 T) was acquired in a patient cohort (n=94) in the Neurosciences Intensive Care Unit (NICU) of an academic medical center in the follow-up window during treatment for ischemic stroke (IS) and hemorrhagic stroke (HS). A deep-learning architecture was applied to produce AI estimates of midline shift (MLS-AI). Neuroradiologist annotations for MLS were compared to MLS-AI using non-inferiority testing. Regression analysis was used to evaluate associations between MLS-AI and stroke severity (NIHSS) and functional disability (mRS) at imaging time and discharge, and the predictive value of MLS-AI versus clinical outcome was evaluated. Results: MLS-AI was non-inferior to neuroradiologist estimates of MLS (p<1e-5). MLS-AI measurements were associated with stroke severity (NIHSS) near the time of imaging in all patients (p<0.005) and within the IS subgroup (p=0.005). In multivariate analysis, larger MLS-AI at the time of imaging was associated with significantly worse outcome at the time of discharge in all patients and in the IS subgroup (p<0.05). POC-MRI with MLS-AI >1.5 mm was positively predictive of poor discharge outcome in all patients (PPV=70%) and specifically in patients with IS (PPV=77%).

OBJECTIVE To evaluate changes in insulin sensitivity, hormone secretion, and hepatic steatosis immediately after caloric restriction, vertical sleeve gastrectomy (VSG), and Roux-en-Y gastric bypass (RYGB). RESEARCH DESIGN AND METHODS Obese subjects were assessed for: 1) insulin sensitivity by hyperinsulinemic-euglycemic clamp with glucose tracer infusion, 2) adipokine concentrations by sampling serum and subcutaneous adipose interstitial fluid, and 3) hepatic fat content by magnetic resonance imaging before and 7-10 days after VSG, RYGB, or supervised caloric restriction. RESULTS Each group exhibited an approximately 5% total body weight loss, accompanied by similar improvements in hepatic glucose production and hepatic, skeletal muscle, and adipose tissue insulin sensitivity. Leptin concentrations in plasma and adipose interstitial fluid were equally decreased and reductions in hepatic fat were similar. CONCLUSIONS The improvements in insulin sensitivity and adipokine secretion observed early after bariatric surgery are replicated by equivalent caloric restriction and weight loss.

Magnetic resonance imaging (MRI) allows important visualization of the brain and central nervous system anatomy and organization. However, unlike electroencephalography (EEG) or functional near infrared spectroscopy, which can be brought to a patient or study participant, MRI remains a hospital or center-based modality. Low magnetic field strength MRI systems, however, offer the potential to extend beyond these traditional hospital and imaging center boundaries. Here we describe the development of a modified cargo van that incorporates a removable low-field permanent magnet MRI system and demonstrate its proof-of-concept. Using phantom scans and in vivo T2-weighted neuroimaging data, we show no significant differences with respect to geometric distortion, signal-to-noise ratio, or tissue segmentation outcomes in data acquired in the mobile system compared to a similar static system in a laboratory setting. These encouraging results show, for the first time, MRI that can be performed at a participant's home, community center, school, etc. Breaking traditional barriers of access, this mobile approach may enable imaging of patients and participants who have mobility challenges, live long distances from imaging centers, or are otherwise unable to travel to an imaging center or hospital.

Neuroimaging is crucial for assessing mass effect in brain-injured patients. Transport to an imaging suite, however, is challenging for critically ill patients. We evaluated the use of a low magnetic field, portable MRI (pMRI) for assessing midline shift (MLS). In this observational study, 0.064 T pMRI exams were performed on stroke patients admitted to the neuroscience intensive care unit at Yale New Haven Hospital. Dichotomous (present or absent) and continuous MLS measurements were obtained on pMRI exams and locally available and accessible standard-of-care imaging exams (CT or MRI). We evaluated the agreement between pMRI and standard-of-care measurements. Additionally, we assessed the relationship between pMRI-based MLS and functional outcome (modified Rankin Scale). A total of 102 patients were included in the final study (48 ischemic stroke; 54 intracranial hemorrhage). There was significant concordance between pMRI and standard-of-care measurements (dichotomous, κ = 0.87; continuous, ICC = 0.94). Low-field pMRI identified MLS with a sensitivity of 0.93 and specificity of 0.96. Moreover, pMRI MLS assessments predicted poor clinical outcome at discharge (dichotomous: adjusted OR 7.98, 95% CI 2.07–40.04 , p = 0.005; continuous: adjusted OR 1.59, 95% CI 1.11–2.49, p = 0.021). Low-field pMRI may serve as a valuable bedside tool for detecting mass effect.

Radio frequency (RF) spike noise is a common source of exogenous image corruption in MRI. Spikes occur as point-like disturbances of $k$-space that lead to global sinusoidal intensity errors in the image domain. Depending on the amplitude of the disturbances and their locations in $k$-space, the effect of a spike can be significant, often ruining the reconstructed images. Here we present both a spike detection method and a related data correction method for automatic correction of RF spike noise. To detect spikes, we found the $k$-space points that have the most significant effect on the total variation of the image. To replace the spikes, we used a compressed sensing reconstruction in which only the points thought to be corrupted are unconstrained. We demonstrated our technique in two cases: (1) in vivo gradient echo brain data with artificially corrupted points and (2) actual, complex scanner data from a whole-body fat-water imaging gradient echo protocol corrupted by spikes at uncertain locations. Our method allowed near-perfect detection and correction with no human intervention. We calculated Matthews correlation coefficients and sensitivities above 0.95 for a maximum of 0.78\% corruption in synthetically corrupted in vivo brain data. We also found specificities above 0.9994.

As interventional oncology services within radiology mature, image-guided ablation techniques are increasingly applied to recurrent gynecologic malignancies. Ablation may be performed using thermal techniques like cryoablation, microwave ablation, or radiofrequency ablation, as well as non-thermal ones, such as focused ultrasound or irreversible electroporation. Feasibility and approach depend on tumor type, size, number, anatomic location, proximity of critical structures, and goals of therapy. Current indications include local control of limited metastatic disease or palliation of painful bone metastases refractory or unsuitable to conventional therapies. Technical aspects of these procedures, including methods to protect nearby critical structures are presented through illustrative examples. Cases amenable to image-guided ablation include, but are not limited to, hepatic or pulmonary metastases, musculoskeletal metastases, retroperitoneal nodal metastases, pelvic side wall disease, abdominal wall disease, and vaginal or vulvar tumors. Protective maneuvers, such as hydro-displacement of bowel, neuromonitoring, and retrograde pyeloperfusion through ureteral stents, permit safe ablation despite close proximity to vulnerable nerves or organs. Image-guided ablation offers an alternative modality to achieve local tumor control without the risks associated with surgery or systemic treatment in appropriately selected patients. A multidisciplinary approach to use of image-guided ablation includes collaboration between gynecologic oncology, interventional radiology, anesthesia, urology and radiation oncology teams allowing for appropriate patient-centered case selection. Long-term follow up and additional studies are needed to determine the oncologic benefits of such techniques.

Background and Aims: Advances in low-field MRI have enabled image acquisition at the point-of-care (POC). We aim to characterize ischemic lesions in low-field, POC MRI and assess its relationship with stroke severity in ischemic stroke patients. Methods: We performed POC MRI exams on ischemic stroke patients. T2-weighted (T2W), fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI) exams were acquired with a 64mT, portable bedside MRI system. Three raters computed signal intensity ratios (SIR) for each sequence. For every slice showing an infarct, an SIR was generated by dividing the mean signal intensity of the lesion by the mean signal intensity of the contralateral hemisphere. Infarct volumes were obtained by multiplying the lesion area of each slice by the slice thickness (5mm) and summing the cross-sectional areas. Volumes were correlated with National Institutes of Health Stroke Scale (NIHSS) scores at the time of scan. Results: We studied 18 ischemic stroke patients (50% women; ages 30-95 years). Two patients were studied at two and three serial timepoints, respectively. POC exams were obtained 2.7 ± 2.2 days after symptom onset. A total of 18 T2W, 17 FLAIR, and 18 DWI exams were obtained. Three exams (1 T2W; 1 FLAIR; 1 DWI) were excluded due to motion degradation. High field MRI exams (19 ± 16 hours from POC exams) demonstrated ischemic infarcts in 15 of the 18 patients. All POC T2W and FLAIR exams revealed infarcts in these patients, and 14 of the 17 DWI exams showed infarcts. Ischemic infarcts were seen as hyperintense lesions (SIR: T2W = 1.19 ± 0.10, FLAIR = 1.15 ± 0.08, DWI = 1.36 ± 0.17). Infarct volume significantly correlated with NIHSS scores (T2W: r = 0.71, p < 0.01; FLAIR: r = 0.65, p < 0.05; DWI: r = 0.65, p < 0.05). Conclusions: These preliminary data suggest that low-field, POC MRI may be useful in the clinical evaluation of ischemic stroke. Further work in larger cohorts is needed to elucidate the appearance of infarction on low-field imaging.

Magnetic resonance imaging (MRI) enables unprecedented visualization of brain and central nervous system anatomy, microstructure, function, and physiology. However, unlike electroencephalography (EEG) or functional near infrared spectroscopy (fNIRS), which can be used within a doctor’s office, research laboratory, or at a participant’s home, MRI remains a hospital or center-based modality. The need for patients or research participants to travel to the scanner limits overall healthcare access and potentially biases research study populations. The recent introduction of low magnetic field strength, lightweight, and portable MRI systems offer the potential to extend beyond these traditional hospital and imaging center boundaries. Here we describe the development and deployment of a mobile imaging lab in a modified cargo van that incorporates a removable low field permanent magnet MRI system. The mobile lab allows, for the first time, rapid and routine ‘residential’ MRI that can be performed at home, community center, school, etc. Breaking traditional barriers of access, this mobile approach will enable imaging of patients and participants who have mobility challenges, live long distances from imaging centers, or are otherwise unable to travel to an imaging center or hospital.

Radiological examination of the brain is a critical determinant of stroke care pathways. Accessible neuroimaging is essential to detect the presence of intracerebral hemorrhage (ICH). Conventional magnetic resonance imaging (MRI) operates at high magnetic field strength (1.5–3 T), which requires an access-controlled environment, rendering MRI often inaccessible. We demonstrate the use of a low-field MRI (0.064 T) for ICH evaluation. Patients were imaged using conventional neuroimaging (non-contrast computerized tomography (CT) or 1.5/3 T MRI) and portable MRI (pMRI) at Yale New Haven Hospital from July 2018 to November 2020. Two board-certified neuroradiologists evaluated a total of 144 pMRI examinations (56 ICH, 48 acute ischemic stroke, 40 healthy controls) and one ICH imaging core lab researcher reviewed the cases of disagreement. Raters correctly detected ICH in 45 of 56 cases (80.4% sensitivity, 95%CI: [0.68–0.90]). Blood-negative cases were correctly identified in 85 of 88 cases (96.6% specificity, 95%CI: [0.90–0.99]). Manually segmented hematoma volumes and ABC/2 estimated volumes on pMRI correlate with conventional imaging volumes (ICC = 0.955, p = 1.69e-30 and ICC = 0.875, p = 1.66e-8, respectively). Hematoma volumes measured on pMRI correlate with NIH stroke scale (NIHSS) and clinical outcome (mRS) at discharge for manual and ABC/2 volumes. Low-field pMRI may be useful in bringing advanced MRI technology to resource-limited settings.

Objective: To demonstrate proof-of-concept for a portable, bedside magnetic resonance imaging (MRI) in acute brain injury using artificial intelligence (AI) based determination of mass effect (ME). Background: High-field MRI requires transport of patients to an imaging suite for data acquisition. Advances in low-field MRI have made it possible to obtain useful imaging at the bedside. While human reader assessment of midline shift (MS) is a conventional measure of mass effect (ME) in brain injury, here we use portable MRI based 3-D images of the brain to assess mass effect using artificial intelligence. Design/Methods: We studied 66 patients with acute brain injury admitted to an intensive care unit who underwent portable 64 mT MRI at the bedside. Three human annotators marked midline shift on T2-weighted or steady-state free precession (SSFP) sequences at the falx, septum, and pineal. A deep learning model was applied using a U-Net neural network and implemented in TensorFlow. Baseline injury severity using National Institutes of Health Stroke Scale Score (NIHSS) and functional outcome at discharge were obtained from the medical record. Statistical analysis was performed in Python. Correlation analysis was done between individual and average scores of human-MS versus AI-ME. Human-MS and AI-ME was correlated against NIHSS. Results: Average human-MS correlated strongly with AI-ME (p=0.01). An average of 9 human-MS measures were required to achieve the level of significance of correlation of AI-ME, however. Individual human-MS ratings also correlated, but less significantly (p=0.03). Individual human-MS measures did not correlate to NIHSS (p=0.55). Average human-MS and AI-ME showed a trend toward correlation to NIHSS (p=0.11 and p=0.07, respectively). Conclusions: These data demonstrate use of a portable MRI device at the bedside in patients with acute brain injury. Portable MR images can be ascertained and interpreted for clinically relevant outcomes such as mass effect using artificial intelligence methods, independent of a human reader. Disclosure: Dr. Sheth has received royalty, license fees, or contractual rights payments from Alva Health. Dr. Sheth holds stock and/or stock options in Alva Health which sponsored research in which Dr. Sheth was involved as an investigator. Dr. Sheth has received research support from Hyperfine, Novartis, Biogen, Bard, Zoll. Dr. Cahn has nothing to disclose. Dr. Salehi has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Hyperfine. Dr. Shah has received research support from Hyperfine Research, Inc.Dr. By has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Hyperfine Research, Inc. Dr. By holds stock and/or stock options in Hyperfine Research, Inc. Dr. Welch has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Hyperfine Research, Inc.. Dr. Welch holds stock and/or stock options in Hyperfine Research, Inc. Dr. Sofka has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Hyperfine. Dr. Sacolick has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Hyperfine Research, Inc.. Dr. Sacolick holds stock and/or stock options in Hyperfine Research, Inc. Dr. Yuen has received research support from Hyperfine Research, Inc. Dr. Mazurek has received research support from Hyperfine Research, Inc. Dr. Matouk has nothing to disclose. Dr. Gordon has nothing to disclose. Dr. Ward has nothing to disclose. Dr. Payabvash has nothing to disclose. Dr. Falcone has nothing to disclose. Dr. Petersen has nothing to disclose. Dr. Schindler has nothing to disclose. Dr. Gilmore has nothing to disclose. Dr. Hwang has nothing to disclose. Dr. Gobeske has nothing to disclose. Dr. Kim has nothing to disclose. Dr. Sansing has nothing to disclose. Dr. Sze has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Hyperfine. Dr. Sze has received research support from Hyperfine. Dr. Rosen has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Hyperfine Research, Inc. Dr. Rosen has received royalty, license fees, or contractual rights payments from BlinkAI. Dr. Rosen holds stock and/or stock options in BlinkAI. Dr. Rosen has received research support from GE Healthcare. Dr. Kimberly has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Biogen. Dr. Kimberly has received research support from Biogen. Dr. Kundu has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Hyperfine.

Background: Radiographic diagnosis of intracranial hemorrhage (ICH) is a critical determinant of stroke care pathways requiring patient transport to a neuroimaging suite. Advances in low-field MRI have made it possible to obtain clinically useful imaging at the point of care (POC). Aim: The aim of this study was to obtain preliminary data regarding the ability of a bedside POC MRI scanner to detect ICH. Methods: We studied 36 patients with a diagnosis of ICH (n=18) or ischemic stroke (n=18). Five blinded readers independently evaluated T2W and FLAIR exams acquired prospectively on a 64 mT, portable bedside MRI system (Hyperfine Research, Inc). Kappa coefficients (κ) were calculated to determine inter-rater agreement. Ground truth was obtained from the clinical report of the closest conventional imaging study (17.9 ± 10.4 hours) and verified by a core reader. For each exam, majority consensus among raters was used to determine sensitivity. Results: ICH volume ranged from 4 to 101 cc (median of 13 cc). Exams were acquired within 7 days of symptom onset (51.1 ± 28.8 hours). A pathologic lesion was identified on every exam with 100% sensitivity. Sensitivity for distinguishing any hemorrhage was 89% and specificity was 83%. The mean sensitivity and specificity for individual raters was 79% and 69%, respectively. When limited to supratentorial hemorrhage, consensus sensitivity was 94%. For ICH cases detected by all raters (n=9), there was 100% accuracy for localizing the bleed (lobar vs. non-lobar) with perfect agreement among raters (κ = 1, p <0.0001). There was substantial agreement for identifying intraventricular hemorrhage (IVH) (κ = 0.72, p < 0.0001). Sensitivity for IVH was 100% based on rater consensus. Figure 1 shows a POC exam with an ICH and IVH. Conclusions: These data suggest that low-field, POC MRI may be used to detect hemorrhagic stroke at the bedside. Further work is needed to evaluate this approach in the hyperacute setting and across a wide range of ICH characteristics.

To obtain preliminary data regarding the ability of a bedside POC MRI scanner to detect ICH.